Ethnobotany of Lao Isan Ethnic Group from Na Chueak District, Maha Sarakham Province, Northeastern Thailand

Abstract

This study investigates the plant diversity, ethnobotanical knowledge, and traditional uses of plants by the Lao Isan ethnic group in Na Chueak District, Maha Sarakham Province, Thailand. A total of 109 plant species, representing 48 families, were identified, with the Fabaceae, Euphorbiaceae, and Rubiaceae families being the most prevalent. This study highlights the ecological and cultural significance of these plants, many of which serve multiple purposes, including food, medicine, and other purposes. A use value analysis revealed that plants such as Schleichera oleosa (Lour.) Oken, Trigonostemon reidioides (Kurz) Craib, and Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q.Nguyen have high functional importance in local cultural and medical practices. The Relative Frequency of Citation indicated that these species are integral to the community’s plant knowledge, with Trigonostemon reidioides and Vietnamosasa pusilla being especially prominent. Additionally, 62 species were identified for medicinal use, emphasizing the community’s reliance on plant-based remedies. This study also discusses the Informant Consensus Factor and Fidelity Level, which reveal strong agreement on the effectiveness of certain plants, particularly for treating digestive, respiratory, and wound healing conditions. This research contributes to the documentation of ethnobotanical knowledge, emphasizing the importance of traditional plant use for cultural continuity and sustainable resource management.

1. Introduction

Throughout human history, plants have played an essential role in providing food, medicine, shelter, and clothing [1,2]. This knowledge of plant use has been passed down through generations and is deeply embedded in the cultures of various ethnic groups [3]. Over time, plant-based knowledge has evolved to meet the changing needs of each generation, particularly in rural and indigenous communities where modern healthcare may be limited [4]. The study of ethnobotany, which focuses on the relationship between people and plants, has gained increasing importance in documenting how different cultures use plants, especially medicinally, and understanding the ecological and cultural implications of this knowledge [5,6].

In many traditional societies, plant knowledge is transmitted orally from elders to younger generations [7]. While effective in maintaining cultural continuity, this method of knowledge transfer makes traditional plant knowledge vulnerable to loss [8]. As communities transition from rural to urban lifestyles and as external influences like globalization and technology impact local practices, the transmission of this vital knowledge is at risk [9]. Younger generations may no longer prioritize learning about plants and their uses, leading to the erosion of a cultural heritage developed over centuries [10].

Thailand is home to a rich diversity of ethnic communities, many of which possess extensive knowledge of plant use for food, medicine, and other practical purposes [11,12,13,14]. Similar concerns have been reported in other parts of Thailand, e.g., studies on Thai Karen and Lawa communities revealed that while traditional knowledge of wild food plants remains rich, younger generations exhibit declining interest in plant-based practices [11]. Likewise, a comparative study among Thai ethnic groups found significant variation in the use and retention of medicinal plant knowledge, with modernization influencing the younger cohorts’ engagement [12]. Among the Tai Yai people in Northern Thailand, traditional medicinal practices are still practiced but face gradual erosion as younger individuals favor modern healthcare approaches [13]. These findings highlight a consistent regional trend: the transmission of ethnobotanical knowledge is increasingly at risk as cultural and lifestyle shifts continue. One such group is the Lao Isan ethnic group, who reside predominantly in the northeastern region of the country [15]. The Isan region, with its rural landscapes and agricultural practices, has profoundly shaped the relationship between local communities and their environment [16]. The Lao Isan people, who constitute the majority population in Na Chueak District, were chosen as the focus of this study due to their strong cultural continuity and extensive traditional knowledge of plant use. Their ethnobotanical practices, deeply embedded in agricultural and domestic activities, have been carefully transmitted across generations. However, the increasing influence of modernization raises concerns about the gradual loss of this invaluable heritage. Thus, documenting and preserving the ethnobotanical knowledge of the Lao Isan community is crucial for maintaining their local wisdom for future generations.

Although numerous ethnobotanical surveys have been carried out in Thailand, large parts of the country—especially the rural areas of the northeast—remain insufficiently explored in terms of traditional plant use [17,18,19,20]. Maha Sarakham Province, located in northeastern Thailand, supports a significant Lao Isan population that continues to depend on natural resources for food, medicine, and cultural practices [18,19]. Despite limited forest cover, the province contains diverse ecosystems that sustain essential plant species [20]. In Na Chueak District, the Lao Isan people possess a profound understanding of their local flora, applying it in medicinal, nutritional, and cultural contexts. However, modernization—particularly among younger generations—has disrupted the transmission of this knowledge [21]. As urbanization spreads and modern healthcare systems take root, traditional plant knowledge and the sustainable practices associated with it face the risk of being forgotten [22,23,24].

The Lao Isan people of Na Chueak District have developed a rich ethnobotanical tradition, with plants being central to daily life. Despite the decline in plant use, these species remain vital to the community’s survival and well-being. The medicinal plants used by the Lao Isan people are a key aspect of their cultural heritage, but their continued use is threatened by changes in lifestyle and increasing reliance on modern medicine [25].

This study aims to address this gap by documenting the plant species used by the Lao Isan ethnic group in the Na Chueak District. By identifying these species and their traditional uses, this research aims to create a comprehensive record of the ethnobotanical knowledge of the community. This documentation will help preserve the valuable traditional knowledge, which is essential for cultural continuity and sustainable resource management. Furthermore, by promoting the use of local plant resources in a sustainable manner, this research will contribute to the long-term conservation of both the community’s cultural heritage and the biodiversity of the region.

2. Materials and Methods

2.1. Study Area

The research area is located in the Na Chueak District, Maha Sarakham Province. This public land is accessible to local communities for a variety of uses (Figure 1). The surrounding communities maintain lifestyles that are closely connected to nature. The landscape is predominantly flat, covered with deciduous forest, and features plateaus and uplands primarily composed of sandy soil. The level terrain makes the area suitable for agriculture, while the higher plateaus are particularly well-suited for growing crops like cassava and sugarcane.

2.2. Data Collection

Plant surveys were carried out in Na Chueak District, Maha Sarakham Province, from January to December 2022. The study involved interviews with experts, traditional healers, elders, and villagers from surrounding communities near the forest area. A total of 400 individuals were interviewed, with 40 individuals (20 males and 20 females) selected from each of the 10 subdistricts in Na Chueak District. This sampling strategy aimed to ensure comprehensive coverage of local knowledge while minimizing bias. Interviews were conducted using open-ended questions to gather information on local plant names, their uses, and the plant parts utilized in three main categories: food, medicine, and other purposes. To enhance data reliability and minimize potential information bias, the collected information was cross-validated with local experts, traditional healers, and elders. The plants identified were documented by their local names, photographed, and sampled for herbarium specimens, which were then deposited at the Vascular Plant Herbarium, Mahasarakham University (VMSU). Species identification was confirmed by comparing the specimens with original descriptions and reference materials from the Plant of the World Online (POWO) [26]. Additionally, a comprehensive review of the relevant taxonomic literature and research databases (such as Scopus, Web of Science, and Google Scholar) was conducted, along with comparisons to digital images from Kew Herbarium and the Kew Science website.

2.3. Data Analysis

2.3.1. Use Value (UV)

The UV represents the importance of a plant species in a specific region, as described by Phillips et al. (1994) [27], and is determined using the following formula:

$$\mathrm{U}{\mathrm{V}}_{\mathrm{s}}={\displaystyle \frac{{\sum }_{\mathrm{i}}{\mathrm{UV}}_{\mathrm{is}}}{{\mathrm{n}}_{\mathrm{s}}}}$$

(1)

where UV_s signifies the total use value of the species, UV_is represents its specific use value, and n_s indicates the number of informants interviewed for that species.

2.3.2. The Relative Frequency of Citation (RFC)

The Relative Frequency of Citation (RFC) is a method used to evaluate the significance of plant species mentioned by informants, as outlined in earlier research. The RFC is determined using the following formula [28]:

RFC = FC/N

(2)

where FC stands for the frequency with which a species is cited, and N is the total number of informants in the study. This index does not consider the specific uses of the plants and ranges between 0 and 1. A value near 0 means very few informants have mentioned the species, while a value of 1 indicates that every informant has referred to it.

2.3.3. The Informant Consensus Factor (F_ic)

The Informant Consensus Factor (F_ic) is used to measure the variation in the use of medicinal plants. It is calculated using the following formula [29]:

$${\mathrm{F}}_{\mathrm{ic}}={\displaystyle \frac{{\mathrm{n}}_{\mathrm{ur}}-{\mathrm{n}}_{\mathrm{t}}}{{\mathrm{n}}_{\mathrm{ur}}-1}}$$

(3)

In this equation, n_ur represents the total number of use reports within a specific category, while n_t denotes the number of plant taxa used in that category.

2.3.4. Fidelity Level (FL)

The Fidelity Level (FL) measures the percentage of informants who identified a particular plant species as a treatment for a specific illness in the study area. It is calculated using the following formula [30]:

$$\mathrm{FL}={\displaystyle \frac{{\mathrm{I}}_{\mathrm{u}}}{{\mathrm{I}}_{\mathrm{p}}}} \times 100$$

(4)

In this equation, I_p represents the number of informants who associated the plant with a particular disease, while I_u refers to the total number of informants who acknowledged the plant’s medicinal use for any health condition.

3. Results

3.1. Plant Diversity in the Community of Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

In total, we registered 109 plant species from 48 families of the Lao Isan Ethnic group from Na Chueak District, Maha Sarakham Province (

Table 1. The diversity of plant species found in Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province, including their vernacular names, conservation status, distribution, utilization, used parts, UV, RFC, and specimen vouchers.

No.	Family	Scientific Name	Vernacular Name	Conservation Status (IUCN) [31]	Conservation Status Proposed by Authors	Distribution	Utilization	Used Parts	UV	RFC	Specimen Vouchers
1.	Amaryllidaceae	Crinum asiaticum L.	Phlapphlueng Pa	NE	LC	Native	O	WP	1.00	0.35	TJ480
2.	Anacardiaceae	Buchanania lanzan Spreng.	Mamuang Hua Maeng Wan	LC	EN	Native	F, O	IC, LE, ST	1.60	0.48	TJ481
3.	Anacardiaceae	Lannea coromandelica (Houtt.) Merr.	Kuk	LC	VU	Native	F, M, O	BA, FT, ST	1.80	0.55	TJ482
4.	Annonaceae	Annona squamosa L.	Mak Khiab	LC	LC	Introduced	F, M	FT	2.00	0.50	TJ483
5.	Annonaceae	Polyalthia debilis (Pierre) Finet & Gagnep.	Kon Khrok	NE	LC	Native	F, M	FT, RO	1.00	0.35	TJ484
6.	Annonaceae	Polyalthia evecta (Pierre) Finet & Gagnep.	Tong Laeng	NE	LC	Native	F, M	FT, RO	1.00	0.35	TJ485
7.	Annonaceae	Uvaria ferruginea Buch.-Ham. ex Hook.f. & Thomson	Tin Tang	NE	VU	Native	M	RO	2.00	0.50	TJ486
8.	Annonaceae	Uvaria rufa (Dunal) Blume	Phi Phuan	NE	LC	Native	F	FT	1.00	0.38	TJ487
9.	Apocynaceae	Amphineurion marginatum (Roxb.) D.J.Middleton	Mok Khruea	NE	VU	Native	F, M, O	LE, RO, ST	2.00	0.50	TJ488
10.	Apocynaceae	Streptocaulon juventas (Lour.) Merr.	Thao Pra Song	NE	LC	Native	M	LA	0.60	0.20	TJ489
11.	Apocynaceae	Urceola polymorpha (Pierre ex Spire) D.J.Middleton & Livsh.	Som Lom	NE	VU	Native	F, M	LE	2.55	0.63	TJ490
12.	Arecaceae	Calamus sp.	Wai	NE	VU	Native	F	SH	1.00	0.38	TJ491
13.	Arecaceae	Cocos nucifera L.	Bak Phrao	NE	LC	Introduced	F	FT	1.00	0.38	TJ492
14.	Arecaceae	Phoenix acaulis Roxb.	Pum Peng	NE	VU	Introduced	O	LE, ST	2.00	0.50	TJ493
15.	Asparagaceae	Asparagus racemosus Willd.	Phakchi Chang	NE	LC	Native	F, M	LE, RO	1.00	0.35	TJ494
16.	Asteraceae	Bidens biternata (Lour.) Merr. & Sherff	Kon Cham	NE	LC	Native	M	ST	1.00	0.35	TJ495
17.	Asteraceae	Blumea balsamifera (L.) DC.	Nat	LC	LC	Native	M	LE	1.00	0.35	TJ496
18.	Asteraceae	Chromolaena odorata (L.) R.M.King & H.Rob.	Thon Lam Hang	NE	LC	Introduced	M	LE	1.00	0.33	TJ497
19.	Asteraceae	Elephantopus scaber L.	Khing Fai Nok Khum	NE	LC	Native	M	WP	0.90	0.33	TJ498
20.	Asteraceae	Gymnanthemum amygdalinum (Delile) Sch.Bip.	Pacha Ngao	NE	LC	Introduced	M	WP	2.00	0.50	TJ499
21.	Bignoniaceae	Millingtonia hortensis L.f.	Kan Khong	LC	LC	Native	M, O	BA, ST	0.60	0.58	TJ500
22.	Bignoniaceae	Oroxylum indicum (L.) Kurz	Lin Fa	LC	LC	Native	O	BA	1.00	0.20	TJ501
23.	Boraginaceae	Ehretia aspera Willd.	Tang Bi	DD	VU	Native	F, M	FT	2.50	0.33	TJ502
24.	Burseraceae	Canarium subulatum Guillaumin	Bak Liam	LC	VU	Native	F, M, O	FT, ST	1.45	0.38	TJ503
25.	Cannabaceae	Trema orientale (L.) Blume	Po Hu	LC	LC	Native	M, O	RO, ST	1.00	0.33	TJ504
26.	Celastraceae	Celastrus paniculatus Willd.	Mak Taek	NE	LC	Native	M	ST	1.00	0.33	TJ505
27.	Celastraceae	Salacia chinensis L.	Ta Kai	LC	LC	Native	M	LE	1.55	0.40	TJ506
28.	Connaraceae	Ellipanthus tomentosus Kurz	Kham Rok	LC	LC	Native	M, O	BA, ST	1.00	0.30	TJ507
29.	Dipterocarpaceae	Dipterocarpus obtusifolius Teijsm. ex Miq.	Hiang	NT	LC	Native	O	ST	1.00	0.30	TJ508
30.	Dipterocarpaceae	Dipterocarpus tuberculatus Roxb.	Phluang	NT	LC	Native	O	ST	1.70	0.53	TJ509
31.	Ebenaceae	Diospyros ehretioides Wall. ex G.Don	Haet Kwang	LC	LC	Native	M	ST	1.00	0.30	TJ510
32.	Ebenaceae	Diospyros martabanica C.B.Clarke	Mak Kluea	NE	LC	Native	M, O	FT, ST	0.60	0.20	TJ511
33.	Ebenaceae	Diospyros rhodocalyx Kurz	Tako	NE	LC	Native	F	FT	1.00	0.30	TJ512
34.	Erythroxylaceae	Erythroxylum cuneatum (Miq.) Kurz	Hun Hai	LC	LC	Native	M	RO	1.55	0.38	TJ513
35.	Euphorbiaceae	Aporosa villosa (Lindl.) Baill.	Muead Lot	LC	LC	Native	M, O	ST	1.00	0.28	TJ514
36.	Euphorbiaceae	Cnidoscolus aconitifolius (Mill.) I.M.Johnst.	Phak Khom Ton	LC	LC	Introduced	F	LE, SH	1.00	0.28	TJ515
37.	Euphorbiaceae	Croton crassifolius Geiseler	Phang Khi	NE	LC	Native	M	RO	1.00	0.28	TJ516
38.	Euphorbiaceae	Croton persimilis Müll.Arg.	Bai Plao	LC	LC	Native	M	LE	1.00	0.30	TJ517
39.	Euphorbiaceae	Croton stellatopilosus H.Ohba	Plao	NE	LC	Native	M	RO	1.00	0.33	TJ518
40.	Euphorbiaceae	Jatropha gossypiifolia L.	Sabu Daeng	LC	LC	Introduced	O	ST	0.95	0.33	TJ519
41.	Euphorbiaceae	Plukenetia volubilis L.	Thua Dao In Kha	NE	LC	Introduced	M	FT	0.70	0.25	TJ520
42.	Euphorbiaceae	Trigonostemon reidioides (Kurz) Craib	Nang Saeng	NE	LC	Native	M	RO	3.00	0.73	TJ521
43.	Fabaceae	Cassia fistula L.	Khun	LC	LC	Doubtful	M, O	SE, ST	2.00	0.53	TJ522
44.	Fabaceae	Dalbergia oliveri Gamble ex Prain	I Meng	CR	CR	Native	O	ST	2.00	0.53	TJ523
45.	Fabaceae	Leucaena leucocephala (Lam.) de Wit	Ka Sed	NE	LC	Introduced	F, O	LE, SE, ST	1.35	0.38	TJ524
46.	Fabaceae	Neptunia oleracea Lour.	Phak Krachet	LC	LC	Native	F	LE, SH	1.00	0.35	TJ525
47.	Fabaceae	Peltophorum dasyrhachis (Miq.) Kurz	A Rang	LC	VU	Native	O	ST	2.90	0.65	TJ526
48.	Fabaceae	Pterocarpus macrocarpus Kurz	Pradu	EN	EN	Native	M, O	BA, ST	1.00	0.38	TJ527
49.	Fabaceae	Senna siamea (Lam.) H.S.Irwin & Barneby	Khilek	LC	VU	Native	F, M, O	LE, ST	2.75	0.65	TJ528
50.	Fabaceae	Sesbania grandiflora (L.) Poir.	Khae Ban	DD	LC	Introduced	F	IC, LE	1.00	0.33	TJ529
51.	Fabaceae	Sesbania javanica Miq.	Sano	LC	LC	Native	F	IC	1.00	0.35	TJ530
52.	Fabaceae	Sindora siamensis Teijsm. ex Miq.	Tae	LC	LC	Native	F, O	SE, ST	1.00	0.30	TJ531
53.	Fabaceae	Tamarindus indica L.	Makham	LC	LC	Introduced	F	FT	0.50	0.18	TJ532
54.	Fabaceae	Xylia xylocarpa (Roxb.) W.Theob.	Daeng	LC	VU	Native	F, M, O	SE, ST	1.65	0.53	TJ533
55.	Hypericaceae	Cratoxylum formosum (Jack) Benth. & Hook.f. ex Dyer	Tiw Khao	LC	VU	Native	F, O	LE, ST	2.00	0.53	TJ534
56.	Irvingiaceae	Irvingia malayana Oliv. ex A.W.Benn.	Mak Bok	LC	EN	Native	F, O	FT, ST	0.50	0.18	TJ535
57.	Lamiaceae	Mesosphaerum suaveolens (L.) Kuntze	I Tu Ton	NE	LC	Introduced	F	LE	2.00	0.53	TJ536
58.	Lauraceae	Litsea glutinosa (Lour.) C.B.Rob.	Mi Men	LC	LC	Native	M, O	LE, ST	2.90	0.70	TJ537
59.	Lecythidaceae	Careya arborea Roxb.	Kra Don	NE	VU	Native	F, M, O	LE, ST	2.15	0.55	TJ538
60.	Loganiaceae	Strychnos nux-blanda A.W.Hill	Tum Ka Khao	LC	VU	Native	F, M, O	BA, FT, ST	1.30	0.38	TJ539
61.	Malvaceae	Bombax anceps Pierre	Ngio Pa	LC	VU	Native	O	BA	1.05	0.35	TJ540
62.	Malvaceae	Grewia abutilifolia Vent. ex Juss.	Khao Chi	LC	LC	Native	F, M	FT, RO	1.30	0.35	TJ541
63.	Malvaceae	Grewia eriocarpa Juss.	Po Kaen Thao	LC	LC	Native	F, O	FT, ST	1.00	0.33	TJ542
64.	Malvaceae	Helicteres angustifolia L.	Khi Tun	NE	LC	Native	M	RO	0.60	0.20	TJ543
65.	Malvaceae	Microcos tomentosa Sm.	Lom Khom	LC	LC	Native	F	FT	1.00	0.35	TJ544
66.	Melastomataceae	Memecylon scutellatum (Lour.) Hook. & Arn.	Mueat Ae	LC	VU	Native	M	RO	2.55	0.60	TJ545
67.	Melastomataceae	Osbeckia stellata Buch.-Ham. ex D.Don	En Ah	NE	VU	Native	M	ST	0.65	0.23	TJ546
68.	Meliaceae	Azadirachta indica A.Juss.	Ka Dao	LC	LC	Native	F, M, O	IC, LE, ST	2.00	0.55	TJ547
69.	Meliaceae	Walsura trichostemon Miq.	Kha Lin	LC	LC	Native	F, O	FT, ST	1.60	0.45	TJ548
70.	Menispermaceae	Cissampelos pareira L.	Khruea Ma Noi	NE	LC	Native	F	LE	1.00	0.38	TJ549
71.	Menispermaceae	Tiliacora triandra (Colebr.) Diels	Ya Nang	NE	LC	Native	F, M	LE	1.00	0.38	TJ550
72.	Menispermaceae	Tinospora crispa (L.) Hook.f. & Thomson	Khruea Ko Ho	NE	LC	Native	M	ST	2.00	0.58	TJ551
73.	Moraceae	Artocarpus heterophyllus Lam.	Khanun	NE	LC	Introduced	F, O	FT	1.00	0.38	TJ552
74.	Moraceae	Artocarpus lacucha Buch.-Ham.	Hat	NE	LC	Native	F	FT	1.00	0.40	TJ553
75.	Moringaceae	Moringa oleifera Lam.	Phak I Hoom	LC	LC	Introduced	F	FT	2.00	0.55	TJ554
76.	Myrtaceae	Eucalyptus globulus Labill.	Yukhaliptas	LC	LC	Introduced	O	ST	1.00	0.40	TJ555
77.	Myrtaceae	Psidium guajava L.	Mak Sida	NE	LC	Introduced	F	FT	1.00	0.40	TJ556
78.	Myrtaceae	Syzygium antisepticum (Blume) Merr. & L.M.Perry	Phak Mek	LC	LC	Native	F	LE	1.00	0.40	TJ557
79.	Myrtaceae	Syzygium cumini (L.) Skeels	Wa	LC	VU	Native	F, O	FT, ST	1.00	0.43	TJ558
80.	Phyllanthaceae	Phyllanthus emblica L.	Makham Pom	LC	LC	Native	F, M, O	FT, ST	2.95	0.68	TJ559
81.	Poaceae	Bambusa bambos (L.) Voss	Phai Pa	NE	LC	Native	F, O	SH, ST	1.00	0.30	TJ560
82.	Poaceae	Bambusa sp.	Phai Noi	NE	LC	Native	O	WP	2.00	0.53	TJ561
83.	Poaceae	Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q.Nguyen	Phek	NE	LC	Native	F, M	SH	3.00	0.70	TJ562
84.	Primulaceae	Embelia ribes Burm.f.	Khi Mot	NE	LC	Native	F	SH	0.40	0.15	TJ563
85.	Rhamnaceae	Ziziphus oenopolia (L.) Mill.	Lep Yiao	LC	LC	Native	F, M	FT, RO	1.65	0.50	TJ564
86.	Rubiaceae	Canthium berberidifolium E.T.Geddes	Ngiang Duk Noi	NE	LC	Native	M	ST	2.00	0.53	TJ565
87.	Rubiaceae	Catunaregam tomentosa (Blume ex DC.) Tirveng.	Khet	NE	LC	Native	M	ST	1.45	0.38	TJ566
88.	Rubiaceae	Discospermum parvifolium Kuntze	Chiang Puen	VU	VU	Native	M	RO	1.00	0.30	TJ567
89.	Rubiaceae	Mitragyna diversifolia (Wall. ex G.Don) Havil.	Thom	LC	LC	Native	O	ST	1.00	0.30	TJ568
90.	Rubiaceae	Morinda pubescens Sm.	Yo Pa	NE	LC	Native	M, O	FT, ST	1.00	0.30	TJ569
91.	Rubiaceae	Paederia linearis Hook.f.	Tot Mu Tot Ma	NE	LC	Native	F	RO	0.80	0.35	TJ570
92.	Rubiaceae	Ridsdalea wittii (Craib) J.T.Pereira	Mak Mo	NE	VU	Native	F, M	FT, ST	0.55	0.20	TJ571
93.	Rutaceae	Citrus hystrix DC.	Bak Kut	LC	LC	Native	F	FT, LE	1.75	0.55	TJ572
94.	Rutaceae	Clausena wallichii Oliv.	Song Fa	LC	LC	Native	F, M	LE, RO	0.70	0.23	TJ573
95.	Rutaceae	Micromelum minutum (G.Forst.) Wight & Arn.	Samat	LC	LC	Native	M	LE	1.00	0.30	TJ574
96.	Salicaceae	Casearia grewiifolia Vent.	Kruai Pa	LC	VU	Native	M, O	BA, ST	2.00	0.53	TJ575
97.	Salicaceae	Flacourtia indica (Burm.f.) Merr.	Bak Ben	LC	VU	Native	F, M	FT	1.60	0.43	TJ576
98.	Sapindaceae	Lepisanthes rubiginosa (Roxb.) Leenh.	Ma Huat	LC	VU	Native	F	FT	1.00	0.25	TJ577
99.	Sapindaceae	Schleichera oleosa (Lour.) Oken	Mak Kho	LC	VU	Native	F, M, O	FT, ST	3.00	0.70	TJ578
100.	Sapotaceae	Xantolis cambodiana (Pierre ex Dubard) P.Royen	Nom Sao	LC	VU	Native	M	BA	1.00	0.25	TJ579
101.	Simaroubaceae	Eurycoma longifolia Jack	Yik Bo Thong	LC	VU	Native	M	RO	1.00	0.25	TJ580
102.	Smilacaceae	Smilax luzonensis C.Presl	Khruea Khiang	NE	LC	Native	F	LE, SH	0.80	0.25	TJ581
103.	Solanaceae	Solanum wrightii Benth.	Makhuea	LC	LC	Native	F	FT	1.00	0.28	TJ582
104.	Stemonaceae	Stemona collinsiae Craib	Nhon Tai Yak	NE	LC	Native	F, M	LE, RO	2.00	0.55	TJ583
105.	Thymelaeaceae	Enkleia malaccensis Griff.	Po Tao Hai	NE	VU	Native	O	ST	1.00	0.28	TJ584
106.	Vitaceae	Cissus repanda (Wight & Arn.) Vahl	Khue Khao Khan	NE	LC	Native	M	LE	1.00	0.28	TJ585
107.	Xanthorrhoeaceae	Aloe vera (L.) Burm.f.	Wan Hangchorakhe	NE	VU	Introduced	O	WP	1.00	0.30	TJ586
108.	Zingiberaceae	Curcuma singularis Gagnep.	Kra Chiao	NE	LC	Native	F	IC	1.00	0.30	TJ587
109.	Zingiberaceae	Kaempferia marginata Carey ex Roscoe	Tup Mup	NE	LC	Native	F, M	LE, RZ	2.00	0.55	TJ588

Abbreviations: Conservation status: critically endangered (CR), data deficient (DD), endangered (EN), least concern (LC), not evaluate (NE), near threatened (NT), vulnerable (VU). Utilization: food (F), medicines (M), other (O). Used parts: bark (BA), fruit (FT), inflorescence (IC), latex (LA), leave (LE), rhizome (RZ), root (RO), seed (SE), shoot (SH), stem (ST), whole plant (WP).

, Figure 2). The notable families frequently represented in the area included the Fabaceae family, with 12 species; the Euphorbiaceae family, with eight species; and the Rubiaceae family, with seven species. Additionally, the Annonaceae, Asteraceae, and Malvaceae families each contributed five species, while Myrtaceae had four species. The Apocynaceae, Arecaceae, Ebenaceae, Menispermaceae, Poaceae, and Rutaceae families were represented by three species each. Furthermore, Anacardiaceae, Bignoniaceae, Celastraceae, Dipterocarpaceae, Melastomataceae, Meliaceae, Moraceae, Salicaceae, Sapindaceae, and Zingiberaceae each had two species. The remaining families were represented by only one species each. Among these, 91 species are native to Thailand, with some native species illustrated in Figure 3.

3.2. The UV of Plants Used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

The high UV (≥2.5) category consists of plants that play significant roles in traditional and ecological practices and are frequently used for various medicinal, cultural, or industrial purposes. Among the highest-valued species are Schleichera oleosa, Trigonostemon reidioides, and Vietnamosasa pusilla (UV = 3.00), all of which are highly regarded for their medicinal and ecological importance. Other plants with high UVs (≥2.5) include Phyllanthus emblica (UV = 2.95), Peltophorum dasyrhachis, and Litsea glutinosa (UV = 2.90), reflecting their broad utilization across multiple sectors.

The medium-use value (2.0–2.49) category includes plants that have a moderate but important role in traditional medicine and other cultural practices. These species are widely used in various regions but are not as universally essential as those in the high-use category. Notable species in this category include Careya arborea (UV = 2.15), Annona squamosa (UV = 2.00), Uvaria ferruginea (UV = 2.00), and Amphineurion marginatum (UV = 2.00), all of which indicate their moderate yet significant presence in local applications. Other species, such as Phoenix acaulis (UV = 2.00), Gymnanthemum amygdalinum (UV = 2.00), and Cassia fistula (UV = 2.00), are valued for their roles in traditional practices, though they may not be as frequently used as the high UV species.

The low-use value (<2.0) category comprises species with relatively limited use in ecological or medicinal contexts. While these plants may hold local significance and be used for specific purposes, their overall contribution is less pronounced compared to those with higher UVs. Species in this category include Jatropha gossypiifolia (UV = 0.95), Elephantopus scaber (UV = 0.90), and Paederia linearis (UV = 0.80). Although these plants may have specialized uses in certain regions, their overall importance is limited when compared to species with higher use values.

The UV analysis underscores the varying levels of importance of plant species used for ecological, medicinal, and cultural purposes. The high UV category highlights species that are integral to local practices and industries, while the medium UV category contains plants with moderate utility. The low UV category indicates species with more specialized or region-specific uses, emphasizing the diverse roles plants play in different ecosystems and human activities [27].

3.3. Relative Frequency of Citation (RFC) of Plants of Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

Based on the collected data (

Table 2. Comparison of the Top 10 UV with the RFC of Plants of Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

Scientific Name	UV	RFC
Trigonostemon reidioides (Kurz) Craib	3.00	0.73
Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q.Nguyen	3.00	0.70
Schleichera oleosa (Lour.) Oken	3.00	0.70
Phyllanthus emblica L.	2.95	0.68
Peltophorum dasyrhachis (Miq.) Kurz	2.90	0.65
Litsea glutinosa (Lour.) C.B.Rob.	2.90	0.70
Senna siamea (Lam.) H.S.Irwin & Barneby	2.75	0.65
Urceola polymorpha (Pierre ex Spire) D.J.Middleton & Livsh.	2.55	0.63
Memecylon scutellatum (Lour.) Hook. & Arn.	2.55	0.60
Ehretia aspera Willd.	2.50	0.58

), the results highlight the significant roles of certain plant species within local traditional and ecological practices. The RFC values reveal the most frequently mentioned species, while the UV reflects the extent of their applications across medicinal, cultural, and industrial uses.

Among the species recorded, Trigonostemon reidioides, Vietnamosasa pusilla, and Schleichera oleosa each had the highest UV (3.00) and demonstrated high RFC values (0.70–0.73), suggesting that these species are not only highly valued and frequently utilized in local practices but also culturally important. The consistently high UV and RFC rankings imply strong, shared traditional knowledge and widespread reliance on these species across the community. Their integral role in both medicinal and ecological applications further confirms their significance in sustaining community health and resource management.

Other species, such as Phyllanthus emblica (UV = 2.95, RFC = 0.68) and Litsea glutinosa (UV = 2.90, RFC = 0.70), also exhibited high UVs, coupled with substantial RFC values, indicating their widespread use in various sectors. These species are commonly cited for their multiple benefits, particularly in traditional medicine and local industry.

Species like Senna siamea (UV = 2.75, RFC = 0.65) and Urceola polymorpha (UV = 2.55, RFC = 0.63) were also frequently mentioned, albeit with slightly lower UVs, suggesting that while they are important in the community’s knowledge systems, their specific applications may be more specialized compared to the highest-ranking species. Similarly, Memecylon scutellatum (UV = 2.55, RFC = 0.60) and Ehretia aspera (UV = 2.50, RFC = 0.58) exhibit moderate presence in local practices with notable but slightly less versatile uses.

The results also revealed species with lower UV and RFC values, such as Jatropha gossypiifolia (UV = 0.95, RFC = 0.33) and Elephantopus scaber (UV = 0.90, RFC = 0.33), indicating that although these species are recognized within certain regions or communities, their uses are more limited in scope.

The findings underscore the diverse roles that plant species play in supporting both ecological balance and human well-being. The relationship between RFC and UV demonstrates that species with high RFC values are frequently mentioned in local knowledge systems, while those with higher UVs are recognized for their broader range of applications, reflecting their cultural, medicinal, and ecological significance.

3.4. Plants Utilization of Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

3.4.1. Plants Used as Food

This study documented the diversity of plant species used as food by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province (Table 1, Figure 4). A total of 58 plant species were identified, distributed across 33 families. The diversity of plant species highlights the rich ethnobotanical knowledge of the community, showcasing a wide range of plants utilized for food, both for sustenance and for cultural practices.

The plant species identified belong to a variety of families, with the Fabaceae family contributing the largest number of species (eight species), followed by Annonaceae with four species. Other families with notable representation include Malvaceae, Myrtaceae, and Anacardiaceae, each contributing three species. A total of 14 families contributed only one species each, indicating a broad but specialized use of various plants across different ecological zones within the forest.

The primary parts utilized are the fruits, which constitute 43.94%, followed by the leaves at 31.82%. Shoots are used at a rate of 10.61%, while inflorescences contribute 7.58%. Seeds and roots are used less frequently, comprising 4.55% and 1.52%, respectively (

Table 3. The diversity of plant species and the methods of using them as food used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

No.	Scientific Name	Used Parts	Method of Uses
1.	Amphineurion marginatum (Roxb.) D.J.Middleton	Leave	Consumed either as fresh vegetables.
2.	Annona squamosa L.	Fruit	Eat as fruit
3.	Artocarpus heterophyllus Lam.	Fruit	Eat as fruit
4.	Artocarpus lacucha Buch.-Ham.	Fruit	Eat as fruit
5.	Asparagus racemosus Willd.	Leave	Consumed as a fresh vegetable or employed in culinary applications to eliminate the fishy odor.
6.	Azadirachta indica A.Juss.	Inflorescence, leave	Consumed either as fresh vegetables.
7.	Bambusa bambos (L.) Voss	Shoot	Consumed either as fresh vegetables.
8.	Buchanania lanzan Spreng.	Inflorescence, leave	Consumed either as fresh vegetables.
9.	Calamus sp.	Shoot	Employed in culinary applications.
10.	Canarium subulatum Guillaumin	Fruit	Eat fresh
11.	Careya arborea Roxb.	Leave	Consumed either as fresh vegetables.
12.	Cissampelos pareira L.	Leave	Utilized as an ingredient in culinary preparations.
13.	Citrus hystrix DC.	Fruit, leave	Utilized as an ingredient in culinary preparations.
14.	Clausena wallichii Oliv.	Leave	Consumed either as fresh vegetables.
15.	Cnidoscolus aconitifolius (Mill.) I.M.Johnst.	Leave, shoot	Boiled and consumed either as vegetables or incorporated into cooking.
16.	Cocos nucifera L.	Fruit	Eat as fruit
17.	Cratoxylum formosum (Jack) Benth. & Hook.f. ex Dyer	Leave	Consumed either as fresh vegetables.
18.	Curcuma singularis Gagnep.	Inflorescence	Boiled and consumed either as vegetables.
19.	Diospyros rhodocalyx Kurz	Fruit	Eat as fruit
20.	Ehretia aspera Willd.	Fruit	Consumed either as fresh vegetables.
21.	Embelia ribes Burm.f.	Shoot	Consumed either as fresh vegetables.
22.	Flacourtia indica (Burm.f.) Merr.	Fruit	Eat as fruit
23.	Grewia abutilifolia Vent. ex Juss.	Fruit	Eat as fruit
24.	Grewia eriocarpa Juss.	Fruit	Eat as fruit
25.	Irvingia malayana Oliv. ex A.W.Benn.	Fruit	Eat as fruit
26.	Kaempferia marginata Carey ex Roscoe	Leave	Consumed either as fresh vegetables.
27.	Lannea coromandelica (Houtt.) Merr.	Fruit	Eat as fruit
28.	Lepisanthes rubiginosa (Roxb.) Leenh.	Fruit	Eat as fruit
29.	Leucaena leucocephala (Lam.) de Wit	Leave, seed	Consumed either as fresh vegetables.
30.	Mesosphaerum suaveolens (L.) Kuntze	Leave	Employed in culinary applications.
31.	Microcos tomentosa Sm.	Fruit	Eat as fruit
32.	Moringa oleifera Lam.	Fruit	Utilized as an ingredient in culinary preparations.
33.	Neptunia oleracea Lour.	Leave, shoot	Consumed either as fresh vegetables.
34.	Paederia linearis Hook.f.	Root	Pounded and then used to make rice pong.
35.	Phyllanthus emblica L.	Fruit	Eat as fruit
36.	Polyalthia debilis (Pierre) Finet & Gagnep.	Fruit	Eat as fruit
37.	Polyalthia evecta (Pierre) Finet & Gagnep.	Fruit	Eat as fruit
38.	Psidium guajava L.	Fruit	Eat as fruit
39.	Ridsdalea wittii (Craib) J.T.Pereira	Fruit	Eat as fruit
40.	Schleichera oleosa (Lour.) Oken	Fruit	Eat as fruit
41.	Senna siamea (Lam.) H.S.Irwin & Barneby	Leave	Boiled and incorporated into cooking.
42.	Sesbania grandiflora (L.) Poir.	Inflorescence, leave	Blanch or use for cooking
43.	Sesbania javanica Miq.	Inflorescence	Boiled and incorporated into cooking.
44.	Sindora siamensis Teijsm. ex Miq.	Seed	Roast until fully cooked.
45.	Smilax luzonensis C.Presl	Leave, shoot	Boiled and consumed either as vegetables or incorporated into cooking.
46.	Solanum wrightii Benth.	Fruit	Consumed either as fresh vegetables.
47.	Stemona collinsiae Craib	Leave	It is utilized in fish sauce jars to prevent the emergence of worms.
48.	Strychnos nux-blanda A.W.Hill	Fruit	Eat as fruit
49.	Syzygium antisepticum (Blume) Merr. & L.M.Perry	Leave	Consumed either as fresh vegetables.
50.	Syzygium cumini (L.) Skeels	Fruit	Eat as fruit
51.	Tamarindus indica L.	Fruit	Eat as fruit
52.	Tiliacora triandra (Colebr.) Diels	Leave	Utilized as an ingredient in culinary preparations.
53.	Urceola polymorpha (Pierre ex Spire) D.J.Middleton & Livsh.	Leave	Consumed either as fresh vegetables.
54.	Uvaria rufa (Dunal) Blume	Fruit	Eat as fruit
55.	Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q.Nguyen	Shoot	Boiled and incorporated into cooking.
56.	Walsura trichostemon Miq.	Fruit	Eat as fruit
57.	Xylia xylocarpa (Roxb.) W.Theob.	Seed	Roast until fully cooked.
58.	Ziziphus oenopolia (L.) Mill.	Fruit	Eat as fruit

, Figure 4).

3.4.2. Plants Used as Medicine

This study explored the diversity of plant species used for medicinal purposes (Table 1, Figure 5). A total of 62 species were identified, distributed across 33 distinct plant families. This diversity highlights the important role of plants in traditional medicine, demonstrating the wide range of therapeutic applications recognized by local communities.

The identified species belong to a broad array of families, with Euphorbiaceae contributing the largest number of species (six), followed by Asteraceae and Rubiaceae, each with five species. Other families with notable representation include Annonaceae and Fabaceae, each contributing four species, and Apocynaceae, with three species. Additionally, the families Boraginaceae, Celastraceae, Ebenaceae, Malvaceae, Melastomataceae, Menispermaceae, Rutaceae, and Salicaceae each contributed two species. In total, 19 families contributed only a single species, indicating a specialized use of particular plants for medicinal purposes. This pattern underscores the rich variety of medicinal plants utilized across different ecological regions and cultural practices. The primary parts utilized are the roots, which account for 26.56%, followed by the stem at 18.75%. Leaves are used at a rate of 17.19%, while the fruit and bark each contribute 12.50%. Seeds and whole plants each make up 3.13%. Latex, rhizomes, shoots, and inflorescences each account for 1.56% (

Table 4. The diversity of plant species, preparation, and ailments used as medicine by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

No.	Scientific Name	Used Parts	Preparation	Ailments
1.	Amphineurion marginatum (Roxb.) D.J.Middleton	Root	Sharpen the roots and drink the solution	Nourish mother’s milk postpartum.
2.	Annona squamosa L.	Fruit	Pounded the fruit and used in hair shampoo	Kill lice
3.	Aporosa villosa (Lindl.) Baill.	Stem	Boiled with water	Treat children with croup
4.	Asparagus racemosus Willd.	Root	Boiled with water	Nourish the body
5.	Azadirachta indica A.Juss.	Leave, inflorescence	Boiled with water	Helps with appetite
6.	Bidens biternata (Lour.) Merr. & Sherff	Stem	Boiled and bathe	Cure psoriasis.
7.	Blumea balsamifera (L.) DC.	Leave	Boiled and bathe	Nourish postpartum
8.	Canarium subulatum Guillaumin	Stem	Soak in water and wash your face	Relieve red and sore eyes
9.	Canthium berberidifolium E.T.Geddes	Stem	Sharpen the stem and apply it to the skin	Relieve pain affected by catfish spines
10.	Careya arborea Roxb.	Leave	Boiled with water	Cure gastritis
11.	Casearia grewiifolia Vent.	Bark	Boiled with water	Drink after giving birth to help heal wounds
12.	Cassia fistula L.	Seed	Dried and boiled with water	Detoxify
13.	Catunaregam tomentosa (Blume ex DC.) Tirveng.	Stem	Boiled with water	Pain reliever
14.	Celastrus paniculatus Willd.	Stem	Boiled and bathe	Aid in postpartum recovery
15.	Chromolaena odorata (L.) R.M.King & H.Rob.	Leave	Pounded and apply to skin or boiled with water	Stop bleeding, treat fever
16.	Cissus repanda (Wight & Arn.) Vahl	Leave	Ground into medicinal dust and combined with aloe vera	Cure stomach aches
17.	Clausena wallichii Oliv.	Root	Sharpen the root and drink	Cure eating disorders in women after giving birth
18.	Croton crassifolius Geiseler	Root	Boiled with water	Nourish the blood
19.	Croton persimilis Müll.Arg.	Leave	Hang it out to dry and then wrap it in a steamed cloth and apply it to the skin	Treat bruises or painful area
20.	Croton stellatopilosus H.Ohba	Root	Boiled with water	Nourish the blood
21.	Diospyros ehretioides Wall. ex G.Don	Stem	Boiled with water	Cure cough and vaginal discharge
22.	Diospyros martabanica C.B.Clarke	Fruit	Eat fresh	Detoxify and treat diarrhea
23.	Discospermum parvifolium Kuntze	Root	Boiled with water	Relieve stomach pain
24.	Ehretia aspera Willd.	Fruit	Eat fresh	Reduce dizziness
25.	Elephantopus scaber L.	Whole plant	Boiled with water	Treat tonic
26.	Ellipanthus tomentosus Kurz	Bark	Boiled with water	Cure gastritis.
27.	Erythroxylum cuneatum (Miq.) Kurz	Root	Boiled with water	Nourishing milk.
28.	Eurycoma longifolia Jack	Root	Sharpen and drink	Cure hemorrhoids
29.	Flacourtia indica (Burm.f.) Merr.	Fruit	Boiled with water	Nourish strength
30.	Grewia abutilifolia Vent. ex Juss.	Root	Boiled with water	Cure urination problems
31.	Gymnanthemum amygdalinum (Delile) Sch.Bip.	Whole plant	Boiled with water	Nourish the body
32.	Helicteres angustifolia L.	Root	Sharpen	Cure boils
33.	Kaempferia marginata Carey ex Roscoe	Rhizome	Boiled with water	Create a pain-relieving remedy. Relieve gas
34.	Lannea coromandelica (Houtt.) Merr.	Bark	Boiled with water	Treat diarrhea
35.	Litsea glutinosa (Lour.) C.B.Rob.	Leave	Crush the leaves with water and use the mixture to wash your hair	Prevent hair loss
36.	Memecylon scutellatum (Lour.) Hook. & Arn.	Root	Sharpen and drink	Nourishing milk
37.	Micromelum minutum (G.Forst.) Wight & Arn.	Leave	Boiled with water	Help expel gas and reduce the symptoms of bloating and distension
38.	Millingtonia hortensis L.f.	Bark, stem	Boiled with water	Relieve cough
39.	Morinda pubescens Sm.	Fruit	Eat fresh	Laxative, relieves bloating and flatulence
40.	Osbeckia stellata Buch.-Ham. ex D.Don	Stem	Boiled with water	Nourish the breast milk after giving birth
41.	Phyllanthus emblica L.	Fruit	Eat fresh	Soothe your throat and reduce coughing
42.	Plukenetia volubilis L.	Fruit	Boiled with water	Nourish the brain and antioxidants
43.	Polyalthia debilis (Pierre) Finet & Gagnep.	Root	Boiled with water	Treat disorders, fever, treat stomach aches
44.	Polyalthia evecta (Pierre) Finet & Gagnep.	Root	Sharpen	Treat fever
45.	Pterocarpus macrocarpus Kurz	Bark	Boiled with water	Relieve bloating and flatulence
46.	Ridsdalea wittii (Craib) J.T.Pereira	Stem	Boiled with water	Treat tendon disease
47.	Salacia chinensis L.	Leave	Boiled with water	Relieve bloating and as a laxative
48.	Schleichera oleosa (Lour.) Oken	Fruit	Eat fresh	Laxative
49.	Senna siamea (Lam.) H.S.Irwin & Barneby	Stem	Eat fresh	Laxative
50.	Stemona collinsiae Craib	Root	Boiled with water	Cure skin diseases and rashes and alleviate itchy lymphatic fluid
51.	Streptocaulon juventas (Lour.) Merr.	Latex	Use externally	Treat mouth sores
52.	Strychnos nux-blanda A.W.Hill	Bark	Chew the bark and blow it onto the wound	Treat snake bites
53.	Tiliacora triandra (Colebr.) Diels	Leave	Boiled with water	Nourish the body
54.	Tinospora crispa (L.) Hook.f. & Thomson	Stem	Boiled with water	Cure fever, stomach ache, and diabetes
55.	Trema orientale (L.) Blume	Root	Boiled with water	Relieve stomach aches and headaches
56.	Trigonostemon reidioides (Kurz) Craib	Root	Sharpen	Cure abscesses, relieve pain
57.	Urceola polymorpha (Pierre ex Spire) J.Middleton & Livsh.	Leave	Eat fresh	Reduce dizziness
58.	Uvaria ferruginea Buch.-Ham. ex Hook.f. & Thomson	Root	Boiled with water	Treat hemorrhoids
59.	Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q.Nguyen	Shoot	Boiled with water	Cure fever
60.	Xantolis cambodiana (Pierre ex Dubard) P.Royen	Bark	Boiled with water	Nourishing milk
61.	Xylia xylocarpa (Roxb.) W.Theob.	Seed	Boiled with water	Relieve aches and pains
62.	Ziziphus oenopolia (L.) Mill.	Root	Boiled with water	Treat abscesses

, Figure 5).

3.4.3. Plants Used for Other Purposes

This study documented the diversity of plant species used for various purposes by the local community in the region. A total of 44 species across 28 plant families were identified (Table 1, Figure 6). The diversity of plant species highlights the wide range of plants utilized for practical and cultural applications, reflecting the community’s profound knowledge of their local flora.

The plant species identified belong to a variety of families, with the Fabaceae family contributing the largest number of species (eight species), followed by Anacardiaceae, Bignoniaceae, Dipterocarpaceae, Euphorbiaceae, Malvaceae, Meliaceae, Myrtaceae, Poaceae, and Rubiaceae, each contributing two species. A total of 18 families contributed only one species each, reflecting the specialized uses of certain plants for specific purposes, such as fabric drying, firewood, or agricultural equipment. These findings underscore the broad but focused application of diverse plant resources across different ecological zones within the study area. The most commonly used part is the stem, making up 84.44%, followed by the whole plant at 6.68%. The bark is utilized at 4.44%, while both the fruit and leaves are used at an equal rate of 2.22% each (

Table 5. The diversity of plant species and the methods of using them for other purposes used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

No.	Scientific Name	Used Parts	Applications
1.	Aloe vera (L.) Burm.f.	Whole plant	Ornamental purpose
2.	Amphineurion marginatum (Roxb.) D.J.Middleton	Stem	Straws for spinning silk threads
3.	Aporosa villosa (Lindl.) Baill.	Stem	Firewood
4.	Artocarpus heterophyllus Lam.	Fruit	Used to make fabric dye, yellow color
5.	Azadirachta indica A.Juss.	Stem	Firewood, building houses, and making furniture
6.	Bambusa bambos (L.) Voss	Stem	Make basketry and equipment such as knife handles
7.	Bambusa sp.	Whole plant	Ornamental purpose
8.	Bombax anceps Pierre	Bark	Used to make fabric dye, brown color
9.	Buchanania lanzan Spreng.	Stem	Firewood
10.	Canarium subulatum Guillaumin	Stem	Firewood and building houses
11.	Careya arborea Roxb.	Stem	Firewood, building houses, and making furniture
12.	Casearia grewiifolia Vent.	Stem	Firewood
13.	Cassia fistula L.	Stem	Firewood, building houses, and making furniture
14.	Cratoxylum formosum (Jack) Benth. & Hook.f. ex Dyer	Stem	Firewood
15.	Crinum asiaticum L.	Whole plant	Ornamental purpose
16.	Dalbergia oliveri Gamble ex Prain	Stem	Firewood
17.	Diospyros martabanica C.B.Clarke	Stem	Make furniture
18.	Dipterocarpus obtusifolius Teijsm. ex Miq.	Stem	Firewood and building houses
19.	Dipterocarpus tuberculatus Roxb.	Stem	Firewood and building houses
20.	Ellipanthus tomentosus Kurz	Stem	Firewood
21.	Enkleia malaccensis Griff.	Stem	Used stem to make rope
22.	Eucalyptus globulus Labill.	Stem	Used to make fabric dye, green color
23.	Grewia eriocarpa Juss.	Stem	Make agricultural equipment such as knife handles
24.	Irvingia malayana Oliv. ex A.W.Benn.	Stem	Firewood, building houses, and making furniture
25.	Jatropha gossypiifolia L.	Stem	Used to make fabric dye, indigo color
26.	Lannea coromandelica (Houtt.) Merr.	Stem	Firewood and building houses
27.	Leucaena leucocephala (Lam.) de Wit	Stem	Firewood
28.	Litsea glutinosa (Lour.) C.B.Rob.	Stem	Firewood
29.	Millingtonia hortensis L.f.	Stem	Firewood
30.	Mitragyna diversifolia (Wall. ex G.Don) Havil.	Stem	Firewood, building houses, and making furniture
31.	Morinda pubescens Sm.	Stem	Firewood
32.	Oroxylum indicum (L.) Kurz	Bark	Used to make fabric dye, light green color
33.	Peltophorum dasyrhachis (Miq.) Kurz	Stem	Firewood
34.	Phoenix acaulis Roxb.	Leave, stem	Make brooms
35.	Phyllanthus emblica L.	Stem	Firewood
36.	Pterocarpus macrocarpus Kurz	Stem	Firewood, building houses, making furniture, making fabric dye, cream color
37.	Schleichera oleosa (Lour.) Oken	Stem	Firewood
38.	Senna siamea (Lam.) H.S.Irwin & Barneby	Stem	Firewood
39.	Sindora siamensis Teijsm. ex Miq.	Stem	Firewood, building houses, and making furniture
40.	Strychnos nux-blanda A.W.Hill	Stem	Firewood
41.	Syzygium cumini (L.) Skeels	Stem	Firewood, building houses, and making furniture
42.	Trema orientale (L.) Blume	Stem	Burn the stems and use them to make firecracker powder
43.	Walsura trichostemon Miq.	Stem	Firewood
44.	Xylia xylocarpa (Roxb.) W.Theob.	Stem	Firewood, building houses, and making furniture

, Figure 6).

3.5. Informant Consensus Factor (F_ic) of Plants Used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

This study assessed the Informant Consensus Factor (F_ic) for various medical categories of the Lao Isan Ethnic group in Na Chueak District, Maha Sarakham Province, providing insight into the local community’s use of plant species for medicinal purposes (

Table 6. Informant Consensus Factor (F_ic) of medical categories Used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

Use-Categories	Disorders Treated	Number of Use Report	Number of Taxa	Fic
Defined symptoms	Dizziness	30	2	0.966
Digestive system	Hemorrhoid, Stomachache, Gastritis, Constipation, Carminative	253	17	0.937
Endocrine system	Diabetes	10	1	1.000
Genitourinary system	Diuretic	11	1	1.000
Infection	Fever, Diarrhea, Abscess, Gonorrhea, Conjunctivitis	128	10	0.929
Injuries	Wound, Aphthous Ulcers	28	2	0.963
Muscular-skeletal system	Muscle pain, Sprain	98	6	0.948
Nutritional disorders	Nutrients supplement	188	11	0.947
Other	Shampoo	40	2	0.974
Poisonings	Sting, Parasite, Insect Repellent	48	4	0.936
Pregnancy/Birth/Puerperium	Lactation stimulant, Recovery (female after giving birth)	172	10	0.947
Respiratory system	Cough	45	3	0.955
Skin disorders	Skin nourishment, Rashes	38	2	0.973

). The F_ic values indicate the level of consensus among informants regarding the use of specific plant species for different health conditions. Higher F_ic values suggest greater agreement among informants about the efficacy of particular plants in treating specific disorders.

A strong consensus was observed for conditions treated by a single plant species, such as Endocrine system disorders (Diabetes) and Genitourinary system issues (Diuretic), each with a F_ic value of 1.000, indicating full agreement among informants on the use of one plant for these ailments. Similarly, other categories with high consensus included Other (Shampoo), which had a F_ic of 0.974, and Skin disorders (skin nourishment, rashes), with a F_ic of 0.973. These categories reflect widespread agreement on the use of specific plant species within the community.

The Muscular-skeletal system (Muscle pain, Sprain) and Pregnancy/Birth/ Puerperium (Lactation stimulant, Recovery after birth) categories, which involved a larger number of use reports (98 and 172, respectively), had slightly lower F_ic values (0.948 and 0.947), indicating strong, but slightly less unanimous consensus. Nutritional disorders (Topic, Nutrients supplement) also showed a similar level of agreement, with a F_ic of 0.947.

In contrast, the Digestive system category, including ailments like hemorrhoids, stomachaches, gastritis, constipation, and carminative uses, had the most extensive range of species (17 taxa) but still retained a notable F_ic value of 0.937, reflecting a broad recognition of plants for treating these conditions.

Other categories, such as Poisonings (Sting, Parasite, Insect Repellent) and Infections (Fever, Diarrhea, Abscess, Gonorrhea, Conjunctivitis), had moderate F_ic values of 0.936 and 0.929, respectively, indicating agreement on the medicinal uses of certain plant species, although with slightly more diversity in the plants used for these conditions.

This diverse pattern of consensus underscores the depth of local knowledge regarding plant-based remedies and the community’s extensive use of specific plants for treating a wide array of health issues across various systems of the body.

3.6. Fidelity Level (FL) of Plants Used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province

The Fidelity Level (FL) of medicinal plants of the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province, shown in

Table 7. Fidelity Level (FL) of medical plants Used by the Lao Isan Ethnic Group in Na Chueak District, Maha Sarakham Province.

Categories	Fidelity Level (%FL)
Defined symptoms	Ehretia aspera and Urceola polymorpha (100)
Digestive system	Careya arborea, Cissus repanda, Discospermum parvifolium, Ellipanthus tomentosus, Eurycoma longifolia, Micromelum minutum, Morinda pubescens, Pterocarpus macrocarpus, Salacia chinensis, Schleichera oleosa, Senna siamea, Trema orientale, and Uvaria ferruginea (100), Kaempferia marginata (60), Tinospora crispa (30), Polyalthia debilis (25), Chromolaena odorata (20)
Endocrine system	Tinospora crispa (50)
Genitourinary system	Grewia abutilifolia (100)
Infection	Canarium subulatum, Helicteres angustifolia, Lannea coromandelica, Polyalthia evecta, Vietnamosasa pusilla and Ziziphus oenopolia (100), Diospyros martabanica (60), Trigonostemon reidioides (47), Polyalthia debilis (25), Tinospora crispa (20)
Injuries	Streptocaulon juventas (100) and Chromolaena odorata (80)
Muscular-skeletal system	Catunaregam tomentosa, Croton persimilis, Ridsdalea wittii, and Xylia xylocarpa (100), Trigonostemon reidioides (53), Kaempferia marginata (40)
Nutritional disorders	Aporosa villosa, Asparagus racemosus, Azadirachta indica, Croton crassifolius, Croton stellatopilosus, Elephantopus scaber, Flacourtia indica, Gymnanthemum amygdalinum, Plukenetia volubilis, and Tiliacora triandra (100), Polyalthia debilis (50)
Other	Annona squamosa and Litsea glutinosa (100)
Poisonings	Canthium berberidifolium, Cassia fistula, and Strychnos nux-blanda (100), Diospyros martabanica (40)
Pregnancy/Birth/Puerperium	Amphineurion marginatum, Blumea balsamifera, Casearia grewiifolia, Celastrus paniculatus, Clausena wallichii, Erythroxylum cuneatum, Memecylon scutellatum, Osbeckia stellate, and Xantolis cambodiana (100), Diospyros ehretioides (59)
Respiratory system	Millingtonia hortensis and Phyllanthus emblica (100), Diospyros ehretioides (41)
Skin disorders	Bidens biternate and Stemona collinsae (100)

, represents the percentage of informants who reported using a particular plant for each corresponding medical category. Plants with a higher FL are those that are commonly used and highly trusted within the community for treating specific disorders.

For defined symptoms, both Ehretia aspera and Urceola polymorpha demonstrated a high fidelity level of 100%, suggesting these species are consistently used for treating these symptoms. Similarly, in the digestive system category, several species, including Careya arborea, Cissus repanda, Discospermum parvifolium, Ellipanthus tomentosus, and others, also exhibited a 100% fidelity level, indicating widespread use across the community for digestive ailments. Other plants, such as Kaempferia marginata (60% FL) and Tinospora crispa (30% FL), are used less frequently but still show some level of recognition within the community for digestive health.

In the endocrine system, Tinospora crispa is used by 50% of informants for treating relevant disorders, suggesting it is a commonly used plant, though not as universally relied upon as other species. For genitourinary system disorders, Grewia abutilifolia showed a high fidelity level of 100%, indicating it is a primary treatment for such issues. In the infection category, several plants, including Canarium subulatum, Helicteres angustifolia, and Lannea coromandelica, also had a 100% FL, suggesting they are considered essential for treating infections. However, plants such as Tinospora crispa (20% FL) are used less frequently for infections.

In the injuries category, both Streptocaulon juventas and Chromolaena odorata were highly regarded, with S. juventas reaching 100% FL and C. odorata showing an 80% FL, reflecting its high use for treating injuries.

Muscular-skeletal system issues were dominated by Catunaregam tomentosa, Croton persimilis, Ridsdalea wittii, and Xylia xylocarpa, all with 100% FL. Other plants like Trigonostemon reidioides (53% FL) and Kaempferia marginata (40% FL) are used, but less universally, for muscle and joint pain.

The nutritional disorders category saw a wide range of plants used, with Aporosa villosa, Asparagus racemosus, and others having a 100% FL, indicating broad acceptance within the community for treating these disorders. Other plants, such as Polyalthia debilis (50% FL), are less common but still play a role in addressing nutritional issues.

For the other category, Annona squamosa and Litsea glutinosa were highly favored, both with a 100% FL, showcasing their essential role in non-specific therapeutic uses. In the poisonings category, Canthium berberidifolium, Cassia fistula, and Strychnos nux-blanda all had a 100% FL, indicating that they are regarded as reliable remedies for poisonings. However, Diospyros martabanica (40% FL) shows a more limited use for this category.

Pregnancy/Birth/Puerperium treatments featured a wide range of plants with Amphineurion marginatum, Blumea balsamifera, and others, all showing a 100% FL, suggesting these plants are integral to postpartum recovery and lactation support. Diospyros ehretioides (59% FL) was also used, albeit to a lesser extent.

In the respiratory system, both Millingtonia hortensis and Phyllanthus emblica had a 100% FL, demonstrating their pivotal role in treating respiratory issues. Diospyros ehretioides (41% FL) was used less frequently for this purpose. Lastly, for skin disorders, both Bidens biternate and Stemona collinsae had a perfect 100% FL, making them key plants for addressing various skin conditions.

3.7. Conservation Status

Based on assessments from the IUCN Red List website [31], among the 109 species examined, 2 species are listed as Data Deficient (DD), 50 as Not Evaluated (NE), 2 as Near Threatened (NT), 52 as Least Concern (LC), and only a few are recognized under threatened categories, including 1 species each as Vulnerable (VU), Endangered (EN), and Critically Endangered (CR). In contrast, the authors’ proposed conservation assessments, based on field observations, updated distribution data, and consideration of plant utilization reports, suggest a notable shift in threat levels: 77 species are categorized as Least Concern (LC), 28 as Vulnerable (VU), 3 as Endangered (EN)—including Buchanania lanzan, Pterocarpus macrocarpus, and Irvingia malayana,—and 1 species, Dalbergia oliveri, is proposed to be Critically Endangered. No species are placed under DD, NE, or NT in the authors’ assessment. During the field survey, it was observed that local communities tend to place greater value on and actively conserve plant species that are directly beneficial to them, as they recognize their long-term utility. As part of the research process, we engaged in knowledge exchange with local residents, particularly emphasizing the importance of sustainable harvesting practices. Fostering local awareness of the ecological and cultural value of native plant resources and encouraging community-led stewardship is often more effective and sustainable than imposing external conservation controls.

4. Discussion

This study investigates the plant diversity, ethnobotanical knowledge, and traditional uses of plants by the Lao Isan ethnic group in Na Chueak District, Maha Sarakham Province. Our findings revealed a rich diversity of 109 plant species belonging to 48 families, with a notable prevalence of species from the Fabaceae, Euphorbiaceae, and Rubiaceae families. These findings not only contribute to understanding the ecological richness of the region but also provide a detailed account of the cultural significance and utility of these plants in local practices.

The results demonstrate a substantial diversity of plant families, with particular emphasis on the Fabaceae, Euphorbiaceae, and Rubiaceae families. These families are dominant in the local flora, and their high representation in the ethnobotanical survey points to their wide-ranging uses in food, medicine, and construction, consistent with ethnobotanical studies in other Southeast Asian regions [32,33,34]. The Fabaceae family, in particular, was found to be the most diverse, with 12 species identified, reflecting its ecological adaptability and significance in both natural ecosystems and human livelihoods. Fabaceae species are frequently used in traditional agriculture, medicine, and nutrition, serving as important sources of protein, fiber, and medicinal compounds [35].

Similarly, the Euphorbiaceae and Rubiaceae families also stood out for their medicinal properties. Euphorbiaceae species, such as Jatropha gossypiifolia, are traditionally used for treating ailments such as wounds, inflammation, and digestive problems [36,37]. The Rubiaceae family, represented by species like Coffee arabica and Morinda citrifolia, provides a range of uses from medicinal to dietary applications, demonstrating their versatility and value in local health systems [38,39].

The richness of plant families in the study area is indicative of the complex relationships between local communities and their environment [40]. The diversity of plant species in Thailand plays a critical role in sustaining local economies and traditional practices [19,41,42]. The Lao Isan people’s comprehensive knowledge of plant species highlights their ability to sustainably manage local resources, utilizing a wide variety of plants for multiple purposes [25].

One of the key elements of this study was the UV analysis, which provides insight into the functional significance of plants within the community [27]. The UVs are an indicator of how frequently and widely a plant is used, and the plants with the highest UVs were also found to be those with the most significant roles in local cultural and medical practices [43]. Schleichera oleosa, Trigonostemon reidioides, and Vietnamosasa pusilla were identified as particularly important species with high UVs, reflecting their multipurpose utility in areas such as food, medicine, and ritual practices [20].

The high UV of Schleichera oleosa and Trigonostemon reidioides aligns with their use in traditional medicine to treat a wide variety of ailments, such as respiratory and digestive issues, which has been reported in other ethnobotanical studies [44,45]. The plants’ high UV suggests they are essential to local healthcare systems, where they fulfill critical roles as herbal remedies. The use of Vietnamosasa pusilla in both medicinal and cultural contexts underscores its importance beyond utilitarian needs, highlighting how plants are also integrated into the cultural identity of Indigenous communities [46].

Medium-use value plants, such as Careya arborea and Annona squamosa, are also integral to the community’s knowledge system, though their uses are often more selective. Careya arborea, for instance, is used in traditional rites and as a food source during certain seasons, while Annona squamosa is used medicinally and for its nutritional benefits [47,48]. These species are important not only for their medicinal uses but also for their seasonal availability, reinforcing the importance of indigenous ecological knowledge and seasonal plant use.

The presence of lower UV plants further illustrates the diversity of the Lao Isan ethnobotanical knowledge, where even less-utilized species contribute to the overall system of plant use. This mirrors findings from studies in other regions, where even species with limited use serve specialized roles in local ecosystems or cultural practices [49].

The Relative Frequency of Citation (RFC) is another critical metric used to understand the popularity and prominence of specific plants in local practices. High RFC values were observed for plants such as Trigonostemon reidioides and Vietnamosasa pusilla, both of which were consistently mentioned by informants. These plants are clearly central to the community’s plant knowledge, both in terms of their medicinal and ecological functions [45,50]. The high RFC of these species confirms that they play an indispensable role in the local healthcare system, being widely recognized and relied upon for the treatment of various illnesses [51]. Although the data collection spanned the entire year, we did not specifically analyze the seasonal variations in plant usage. However, it is important to acknowledge that some plant species may be used seasonally, which could influence the frequency of their citation. This is indirectly reflected in the Relative Frequency of Citation (RFC) values, where species with more consistent year-round availability are likely to show higher RFC values compared to those that are used primarily during certain periods. While we did not specifically address the seasonal aspects, the overall RFC values still offer valuable insights into the general patterns of plant use within the community.

RFC is often associated with the perceived efficacy and cultural significance of plants within indigenous knowledge systems. The plants with high RFC values in this study are not only frequently used but also possess a high level of cultural and ecological relevance, reinforcing the argument that traditional knowledge systems are deeply intertwined with both health and environmental sustainability [52]. Conversely, plants with lower RFC values, such as Elephantopus scaber and Jatropha gossypiifolia, are mentioned less frequently, suggesting that their roles are more specialized or limited to certain individuals or contexts. Nonetheless, these plants may still play critical roles in specific rituals, medicinal practices, or agricultural settings, suggesting that even plants with low RFC values can have niche but important functions within the community [53].

One of the most significant aspects of the Lao Isan plant use is the diverse range of applications across different plant categories. As with many indigenous groups, plants are used for a broad spectrum of needs, including food, medicine, and various other utilitarian purposes. Of the 109 species identified, 58 were primarily used for food, highlighting the importance of plants in ensuring food security and dietary variety. The majority of these species were fruit-bearing trees, such as Durio zibethinus and Moringa oleifera, which are rich in nutrients and widely consumed in the Lao Isan diet. The consumption of these species aligns with studies showing that indigenous peoples in Southeast Asia rely heavily on local plants for nutrition, often incorporating a diverse range of edible plant species into their diets [11,17,19,20,25,33,41,42].

Medicinal plants played a prominent role, with 62 species identified for therapeutic uses. This reflects the community’s reliance on plant-based remedies for treating a wide variety of ailments, such as fever, digestive disorders, and skin conditions. The widespread use of plants like Andrographis paniculata and Plumbago zeylanica for their antimalarial and anti-inflammatory properties reinforces the growing recognition of traditional knowledge systems in addressing modern health challenges. Additionally, many of these plants are used as part of integrated healing systems, where medicinal practices are often intertwined with spiritual and cultural rituals [12,13,22,34,43,53]. However, the community’s reliance on traditional plants has been undergoing dynamic changes due to the increasing availability and popularization of modern medical facilities. While traditional plant-based remedies continue to play a significant role, particularly for common ailments and first-line treatments, there has been a gradual shift toward biomedical healthcare services for more serious or complex conditions. Younger generations, in particular, show a growing preference for hospital-based treatments, reflecting broader trends of modernization and globalization. Nevertheless, traditional knowledge remains resilient among older community members and in remote areas where access to hospitals and clinics may still be limited. This dynamic interaction between traditional practices and modern healthcare highlights a transitional phase, where both systems coexist and adapt in response to changing socio-economic conditions, accessibility, and perceptions of efficacy.

Beyond food and medicine, the Lao Isan people also use plants for a range of other purposes, such as crafting materials, firewood, and tools. Species such as Caryota mitis and Calamus rotang are used for making baskets and other woven items, while others, like Bamboo, are utilized in construction and agricultural tools. This diverse use of plants underscores the integrated relationship between local ecosystems and the cultural practices of the Lao Isan people. Similar patterns have been observed in other ethnobotanical studies, where local flora serves not just practical but also symbolic and cultural purposes [25,54].

The high Informant Consensus Factor (F_ic) values for specific health categories, particularly for disorders related to the digestive system, respiratory conditions, and wound healing, reflect the shared knowledge within the community regarding the effectiveness of certain plants. The F_ic value of 1 indicates complete agreement among informants, emphasizing the reliability and consistency of plant knowledge in the treatment of common ailments. This corroborates findings from other regions where traditional knowledge systems have been shown to possess a high degree of consensus, often developed over generations of practice [17,19].

Similarly, the Fidelity Level (FL) values also provide insight into the trust and dependence placed on specific plants. Plants such as Schleichera oleosa and Ehretia aspera, with FL values of 100%, are regarded as highly effective by all informants for treating particular ailments. These plants are seen as essential tools in the community’s healthcare system, contributing to the resilience of the community’s traditional medical knowledge. FL values also reveal that certain plants are more specialized in their use, with lower FL values indicating that some plants are less universally trusted for treating particular conditions [44].

To alleviate the loss of traditional plant knowledge, several strategies should be considered. Community education programs and workshops can engage both younger and older generations, ensuring that knowledge about the value and use of traditional plants is passed down. Additionally, documenting and sharing this knowledge through digital archives or printed materials can make it accessible for future generations. Encouraging intergenerational knowledge transfer, where elders directly teach younger members, can strengthen the continuity of traditional practices. Plant protection programs focusing on sustainable harvesting and legal protections for endangered species are also crucial. By combining these efforts, communities can preserve their traditional knowledge while ensuring sustainable use and conservation of plant resources.

5. Conclusions

This study documents the plant diversity, ethnobotanical knowledge, and traditional uses among the Lao Isan ethnic group in Na Chueak District, Maha Sarakham Province. We identified 109 species (48 families), with Fabaceae, Euphorbiaceae, and Rubiaceae as the most prevalent. Key species like Schleichera oleosa, Trigonostemon reidioides, and Vietnamosasa pusilla showed high Use Value (UV) and Relative Frequency of Citation (RFC), underscoring their cultural and medicinal importance. Of 62 medicinal plants, a strong consensus (via Fic and FL) highlighted their efficacy for digestive, respiratory, and wound treatments. The findings stress the importance of fostering intergenerational knowledge transfer, promoting community-based education, and implementing sustainable harvesting and legal protection measures to conserve plant resources. Future research could focus on integrating traditional and modern healthcare systems, enhancing the conservation of valuable plant species, and supporting the continued relevance of traditional plant knowledge in a changing world, thereby safeguarding the cultural and ecological heritage of the Lao Isan community and similar groups across Southeast Asia.