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Article

Chemical Composition and Biological Activities of Chromolaena odorata (L.) R.M.King & H.Rob. Essential Oils from Central Vietnam

by
Hoa Van Vo
1,
Prabodh Satyal
2,
Thuong Thanh Vo
1,
Truc Thi-Thanh Le
1,
An Thi-Giang Nguyen
3,
Hien Thi Vu
4,
Trung Thanh Nguyen
5,
Hung Huy Nguyen
6,* and
William N. Setzer
2,7
1
Department of Pharmacy, Duy Tan University, 03 Quang Trung, Da Nang 550000, Vietnam
2
Aromatic Plant Research Center, 230 N 1200 E, Suite 100, Lehi, UT 84043, USA
3
Faculty of Biology, College of Education, Vinh University, 182 Le Duan, Vinh City 4300, Vietnam
4
Faculty of Hydrometeorology and Water resources, Ho Chi Minh City University of Natural Resources and Environment, Ho Chi Minh City 70000, Vietnam
5
Center for Pharmaceutical Biotechnology, College of Medicine and Pharmacy, Duy Tan University, 03 Quang Trung, Danang 550000, Vietnam
6
Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang 5000, Vietnam
7
Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA
*
Author to whom correspondence should be addressed.
Molecules 2025, 30(17), 3602; https://doi.org/10.3390/molecules30173602
Submission received: 30 May 2025 / Revised: 4 August 2025 / Accepted: 5 August 2025 / Published: 3 September 2025
(This article belongs to the Special Issue Advances in Natural Products and Their Biological Activities)
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Abstract

The chemical composition of leaf essential oil of the harmful invasive species Chromolaena odorata collected in Vietnam was analyzed by GC/MS and chiral GC. All three essential oil samples (O1, O2 and O3) in this study fell into chemotype I characterized by α-pinene/geigerene/germacrene D/(E)-β-caryophyllene from a total of six different chemotypes. Chemotype I demonstrated larvicidal effects against Aedes aegypti (Linnaeus, 1762), Aedes albopictus Aedes albopictus (Skuse, 1894), Culex fuscocephala (Theobald, 1907) and Culex quinquefasciatus (Say, 1823), with 24 h LC50 values ranging from 11.73 to 69.87 µg/mL. In contrast, its microemulsion formulation exhibited enhanced toxicity, yielding 24 h LC50 values between 11.16 and 32.43 µg/mL. This chemotype also showed repellent efficacy against Ae. aegypti, with protection times ranging from 70.75 to 122.7 min. Fumigant toxicity was observed against Aedes aegypti, with LC50 values of 40.27% at 0.5 h and 0.34% at 24 h. Molluscicidal activity was recorded with 48 h LC50 values between 3.82 and 54.38 µg/mL against Indoplanorbis exustus (Deshayes, 1833), Pomacea canaliculate (Lamarck, 1822), Physa acuta (Draparnaud, 1805). Additionally, the chemotype exhibited acetylcholinesterase inhibitory activity, with an IC50 value of 70.85 µg/mL. Antimicrobial potential was also demonstrated, with MIC values ranging from 2.0 to 128.0 µg/mL against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella enterica, and Candida albicans. The C. odorata essential oil can be considered as a potential bioresource for human health protection strategies.

Graphical Abstract

1. Introduction

Chromolaena odorata (L.) R.M.King & H.Rob. is a long-lived shrub belonging to the Asteraceae family, originally native to the tropical and subtropical areas of Central and South America, including regions such as Mexico, the Caribbean, and Brazil. Due to a combination of anthropogenic factors—including global trade, tourism, transportation, and alterations in land use—and natural dispersal mechanisms—such as wind, water currents, runoff, and animal movement—the species has extended its range across Africa, Oceania, and parts of South and Southeast Asia. It is widely regarded as a highly invasive weed, particularly in tropical perennial crop systems such as coffee, cocoa, and citrus plantations [1]. C. odorata has widely colonized secondary forest habitats from northern to southeastern Vietnam, where its presence inhibits the regeneration and establishment of native plant species [2]. Despite being classified as a harmful invasive species, C. odorata is regarded in this study as a promising and readily available raw material for the development of essential oil-based products. These products have potential applications in health protection strategies, including biopesticides, antibiotics, and aromatherapy for supporting the treatment of Alzheimer’s disease. Several studies have reported that the essential oil yield of C. odorata ranges from approximately 0.85% to 1.03% [3,4]. This relatively high yield, combined with the plant’s availability, represents a significant advantage in terms of efficiency and cost-effectiveness for large-scale industrial production [5].
This study investigates the chemical makeup and biological activity of C. odorata essential oils and their potential to control three medically important mosquito species: Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus. Aedes mosquitoes are major carriers of arboviruses like dengue [6], Zika [7], yellow fever [8], and chikungunya [9,10,11], while C. quinquefasciatus transmits the filarial worm Wuchereria bancrofti [12] and has been linked to the spread of Rift Valley fever and possibly urban Zika transmission [13].
We also evaluated molluscicidal activity against freshwater snails as intermediate hosts for parasitic diseases. I. exustus transmits cattle schistosomiasis, human cercarial dermatitis, and liver flukes (Fasciola hepatica, F. gigantica) [14], as well as other trematodes like Paramphistomum and Echinostoma [15]. P. acuta, an invasive species, hosts parasites such as Angiostrongylus cantonensis [16], Echinostoma revolutum [17], Posthodiplostomum minimum, and Hypoderaeum conoideum [18]. P. canaliculata spreads A. cantonensis [19] and Gnathostoma spinigerum [20] while damaging rice crops [21].
This study also evaluated the antimicrobial activities against major bacterial and fungal species capable of multidrug resistance, which are listed as common causative agents of community- and hospital-acquired infections, including E. faecalis, S. aureus, B. cereus, E. coli, P. aeruginosa, S. enterica, and C. albicans [22,23,24].
Essential oils and their constituents have demonstrated potential neurological effects, including therapeutic roles in neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases [25]. Due to their low molecular weight and lipophilic nature, these compounds can efficiently cross the blood–brain barrier [25]. Furthermore, their volatility enables administration via inhalation, thereby bypassing hepatic metabolism, which could otherwise degrade bioactive compounds [26]. Therefore, in this study, we also evaluated the acetylcholinesterase (AChE) inhibitory activity of C. odorata essential oil.

2. Results and Discussion

2.1. Chemical Profiles of Essential Oils

The extraction yields of the three essential oil samples O1, O2 and O3 were 0.31, 0.32 and 0.30% (w/w) on fresh weight, respectively. Chemical compositions of C. odorata essential oils from Vietnam are presented in Table 1. These three essential oils have a similar chemical composition, with the main components being α-pinene (11.47–19.24%), germacrene D (11.67–15.12%), (E)-β-caryophyllene (9.56–11.24%) and geijerene (8.96–10.55%), followed by components β-pinene (3.95–7.50%), δ-cadinene (4.38–5.73%), caryophyllene oxide (4.40–5.33%) and α-copaene (4.02–5.26%).
In order to place the essential oil compositions of C. odorata from Vietnam in this study with essential oil compositions from other geographical locations reported in the literature, an agglomerative hierarchical cluster (AHC) analysis was carried out (Figure 1). The cluster analysis revealed at least six chemical clusters: (I) α-pinene/geigerene/germacrene D/(E)-β-caryophyllene, (II) geigerene, (III) α-pinene, (IV) pregeijerene/(E)-caryophyllene/germacrene D, (V) pregeijerene, and (VI) caryophyllene oxide. The samples from Vietnam that fall into cluster I are O1, O2, O3 and O39, while the two samples O4 and O38 fall into clusters II and III, respectively. A principal component analysis (PCA) was carried out to verify the AHC analysis (Figure 2), and it confirms the correlation of the samples from Vietnam with geigerene, germacrene D, and (E)-β-caryophyllene.
To our knowledge, this is the first time that the enantiomeric distribution of monoterpenes in C. odorata essential oils has been determined. The enantiomeric distribution of monoterpenes in C. odorata essential oils was similar among the three essential oil samples. However, when compared with essential oils of other Asteraceae species that have been analyzed by enantioselective GC-MS, there do not seem to be consistent trends in enantiomeric distributions (Table 2). Thus, for example, (+)-sabinene was the predominant enantiomer in C. odorata but was variable in other members of the family. (+)-β-pinene was dominant in C. odorata but is often the minor enantiomer is other members of the family (e.g., Artemisia ludoviciana, Ambrosia acanthicarpa [42], Achillea millefolium var. occidentalis [43], and Ericameria nauseosa [44]). Although (+)-limonene was the major enantiomer in C. odorata, the distribution seems to be variable in other members of the Asteraceae.

2.2. Characteristics of Microemulsion Formulas

The microemulsion formulations exhibited physical parameters (particle size and PDI) ranging from 15.9 to 27.7 nm and 0.068 to 0.100 at T1 and in the range of 28.7–53.3 nm and 0.363–0.549 at T2, respectively (Figure 3).
The combination of alcohols and surfactants in microemulsion (ME) formulation is well established [45,46,47,48,49]. Short-chain alcohols reduce droplet size and improve oil solubilization in oil–water MEs [50]. Awad et al. reported uniform droplet formation in Tween 80/MCT emulsions at MCT concentrations below 1% [51].

2.3. Larvicidal Activity

The essential oil samples exhibited larvicidal activity after 24 h of exposure, with 24 h LC50 values ranging from 43.53 to 53.46, 44.08 to 69.87, 27.25 to 44.34 and 11.73 to 31.97 µg/mL against Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus and Cx. fuscocephala, respectively (Table 3). After 48 h of exposure, 48 h LC50 values ranged from 41.05 to 45.23, 23.04 to 38.89, 19.45 to 34.87, and 10.53 to 29.76 µg/mL against Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus and Cx. fuscocephala, respectively (Table 3 and Table 4) (Figure 4 and Figure 5). MO1 microemulsion exhibited stronger toxicity than its essential oil, with 24 h LC50 values of 32.43, 29.81 and 11.16 µg/mL against Ae. aegypti, Ae. albopictus, and Cx. fuscocephala, respectively (Table 3 and Table 4). The larvicidal efficacy of sample O1 was significantly higher than that of O2 and O3 against Ae. albopictus, Cx. quinquefasciatus, and Cx. fuscocephala (p < 0.05). A similar pattern was noted for Ae. aegypti, though the difference did not reach statistical significance (p > 0.05) (Figure 4 and Figure 5). MO1 showed more stable activity at low concentrations than the essential oils (Figure 4 and Figure 5). Hung et al. (2022) described essential oils with 24 h LC50 values between 10 μg/mL and 50 μg/mL as very active and 24 h LC50 between 50 μg/mL and 100 μg/mL as moderately active [52]. Dias and Moraes (2014) and Pavela (2015) reviewed the larvicidal properties of essential oils and proposed that those exhibiting 24 h LC50 values below 100 µg/mL should be classified as active agents [53,54]. Therefore, the free essential oils and MO1 microemulsion formulation can be considered as potential mosquito larvicides.
Earlier investigations have demonstrated that (E)-β-caryophyllene possesses notable larvicidal activity against Aedes aegypti and Aedes albopictus, with 24 h LC50 values ranging from 56.87 to 70.80 µg/mL. In contrast, caryophyllene oxide showed comparatively weaker larvicidal effects against Ae. aegypti, with 24 h LC50 values reported between 127.9 and 136.6 µg/mL [55,56]. α-Humulene demonstrated larvicidal activity against Ae. aegypti and Ae. albopictus, with 24 h LC50 values ranging from 44.43 to 48.19 µg/mL and 31.49 to 43.86 µg/mL, respectively. In comparison, α-pinene exhibited stronger larvicidal effects against both species, with 24 h LC50 values between 12.94 and 23.05 µg/mL [56,57]. Germacrene D exhibited larvicidal activity against Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus with 24 h LC50 values of 18.76–21.28 μg/mL, while β-pinene exhibited 24 h L50 values in the range of 27.69–32.23 g/mL [58]. Geijerene exhibited stronger larvicidal activity against Ae. aegypti and Anopheles stephensi than Germacrene D [59].

2.4. Repellent Activity

The repellent activity of O1 against Ae. aegypti adults was higher than that of O3; however, the difference was not statistically significant (p > 0.05) (Figure 6). Essential oils are classified as highly effective repellents when their activity persists for more than 120 min, as reported in studies by Sritabutra et al. (2013) and Sutthanont et al. (2022) [60,61].
Some studies have reported that caryophyllene oxide and (E)-β-caryophyllene display repellent effects against Ae. aegypti and An. quadrimaculatus [62,63,64]. Germacrene D has been reported to exhibit repellent activity against Myzus persicae and Acyrthosiphon pisum [65]. Kiran and Pushpalatha (2013) reported that germacrene D and geijerene had strong repellent activity against adults of Ae. aegypti and An. gambiae [66]. Germacrene D and its mixture with α-pinene exhibited strong repellent activity against adults of Ae. albopictus, while the mixture of α-pinene and β-pinene exhibited weak repellent activity [67]. O1 contained a higher concentration of sesquiterpenoids compared to O3, whereas monoterpenoids were more abundant in O3. This compositional trend was also observed among the predominant sesquiterpenoid and monoterpenoid constituents. Such differences in chemical profiles may account for the variation in repellent efficacy observed between the O1 and O3 samples.

2.5. Fumigation Toxicity

O1 essential oil exhibited fumigant toxicity against Ae. aegypti at 0.5 and 24 h with LC50 values of 40.27% and 0.34%, respectively (Table 5). The essential oil of Zingiber cassumunar, which is composed predominantly of monoterpenoids (90.0%), has been shown to possess fumigant toxicity against Ae. albopictus, with LC50 values of 23.60% and 2.10% (v/v) following 0.5 and 24 h of exposure, respectively [68] (Li et al., 2021). Van et al. (2025) investigated the fumigant effect of Zanthoxylum armatum fruit essential oil, rich in monoterpenoids (95.11%), and found an LC50 of 0.52% after 1440 min of exposure [69]. In a similar context, Lucia et al. (2009) assessed the fumigant potential of essential oils extracted from 13 different Eucalyptus species against Ae. aegypti, applying an undiluted 10 µL dose and recording KT50 values between 4.19 and 12.03 min [70]. In this study, at 25% concentration, KT50 was 31.32 min (Table 6). Thus, the fumigant activity of C. odorata essential oil (O1) can be considered significant.
A study by Ma et al. (2020) reported that the compounds β-caryophyllene and α-pinene exhibited comparable fumigant activities, and both were more potent than caryophyllene oxide against Megoura japonica, Plutella xylostella, and Sitophilus zeamais [71]. β-Pinene was reported to have weaker fumigant activity against adults of Lycoriella mali than α-pinene [72]. Geijerene exhibited strong acute toxicity, while germacrene D exhibited moderate activity against Spodoptera litura [73].

2.6. Molluscicidal Activity

The essential oil samples O1, O2 and O3 were active against P. acuta, I. exustus and P. canaliculata with 48 h LC50 values in the ranges of 3.82–6.89, 21.88–26.97 and 25.80–54.38 µg/mL, respectively (Table 7). Essential oil O1 tended to exhibit stronger molluscicide activity than the two essential oil samples O2 and O3, as clearly shown by the mortality rate of snails at different concentrations (Figure 7). Microemulsion MO1 exhibited molluscicidal activity against I. exustus and P. canaliculata comparable to its free essential oil (O1), with 48 h LC50 values of 22.47 and 30.06 µg/mL, respectively (Figure 7).
Bacterial extracts derived from Xenorhabdus and Photorhabdus demonstrated molluscicidal activity against I. exustus, with 72 h LC50 values ranging from 89.81 to 100.32 μg/mL [74]. A cardiac glycoside-enriched fraction obtained from the leaves of Nerium indicum exhibited a 48 h LC50 of 20.12 μg/mL [74]. The methanolic extract of Ambrosia artemisiifolia produced a 24 h LC50 of 194 μg/mL, with sesquiterpene lactones identified as the active constituents, namely psilostachyin (LC50 of 15.9 μg/mL) and psilostachyin B (LC50 of 27.0 μg/mL) [75]. Additionally, three triterpenoids isolated from the methanol bark extract of Eucalyptus exserta displayed molluscicidal effects against P. canaliculata, with 72 h LC50 values of 27.3–42.6 μg/mL [76]. Thus, the essential oil samples O1, O2, and O3 and microemulsion MO1 can be compared with other biological molluscicides.
The sesquiterpenoids caryophyllene oxide, α-humulene, (E)-β-caryophyllene and α-pinene exhibited molluscicide activity with 48 h LC50 < 20 g/mL against P. acuta, I. exustus [57] and P. canaliculata [56].

2.7. AChE Inhibitory Activity

The O1 essential oil sample exhibited acetylcholinesterase inhibitory activity that was considered to be potent [77], with an IC50 value of 70.85 ± 5.47 µg/mL (Table 8). Thus, it is possible that the inhibition of acetylcholinesterase may be responsible for the insecticidal activities of this oil. In this study, α-pinene exhibited an IC50 value of 86.51 ± 6.24 µg/mL (0.64 ± 0.05 mM). Furthermore, this essential oil sample also shows potential for further research on aromatherapy to support the treatment of Alzheimer’s disease by inhibiting acetylcholinesterase [77]. The major constituents (E)-β-caryophyllene, β-pinene, and limonene were reported to have acetylcholinesterase inhibitory activity with IC50 values of 89.10, 71.45 and 53.16 µg/mL, respectively. The two compounds α-humulene and caryophyllene oxide exhibited IC50 values of 160.48 and 320.16 µg/mL, respectively [77]. (E)-β-Caryophyllene has been shown to inhibit acetylcholinesterase (AChE) from Electrophorus electricus (electric eel) by 32% at a concentration of 0.06 mM [78], while its inhibitory activity against AChE from human erythrocytes was reported with an IC50 value of 147 ± 15 µM [79]. Similarly, (E)-β-caryophyllene oxide demonstrated a 41.46 ± 2.66% inhibition of eel AChE at 200 µg/mL [80], and 35.0 ± 4.7% inhibition of bovine erythrocyte AChE at 250 µg/mL [81]. The essential oil of Knema hookeriana consisting of (E)-β-caryophyllene (26.2%), germacrene D (12.5%), δ-cadinene (9.2%), germacrene B (8.8%) and bicyclogermacrene (5.5%) exhibited an IC50 value of 70.5 µg/mL [82].

2.8. Antimicrobial Activity

The three essential oil samples exhibited significantly different antimicrobial activities. Among them, O2 demonstrated the highest potency, with IC50 values ranging from 0.53 to 3.17 µg/mL, whereas O1 showed the lowest activity, with IC50 values ranging from 9.34 to 42.56 µg/mL (Table 9). The essential oil of Croton hirtus, characterized by (E)-β-caryophyllene (32.8%), germacrene D (11.6%), β-elemene (9.1%), α-humulene (8.5%), and caryophyllene oxide (5.0%) as its major constituents, exhibited antimicrobial activity with IC50 values ranging from 3.12 to 5.98 μg/mL. Individually, (E)-β-caryophyllene, α-humulene, and caryophyllene oxide showed IC50 values in the ranges of 9.35–21.46 μg/mL, 3.24–10.45 μg/mL, and 2.67–12.56 μg/mL, respectively [83].

3. Materials and Methods

3.1. Plant Material

Fresh leaves of C. odorata were collected at the same time (June 2022) at three different locations, namely Da Nang (O1, GPS: 16°02′32″ N 108°08′09″ E), Quang Tri (O2, GPS: 16°46′28.4″ N 107°19′30.2″ E) and Quang Binh (O3, GPS: 17°18′08″ N 106°39′54″ E).

3.2. Hydrodistillation

Fresh leaves (O1: 5.0 kg; O2: 0.5 kg; O3: 1.0 kg) were chopped and subjected to hydrodistillation for 5 h using a Clevenger-type apparatus (Witeg Labortechnik, Wertheim, Germany). The essential oil yield was calculated as the mean of three replicates. The obtained oil was dried over anhydrous Na2SO4 and stored in sealed glass vials at 4 °C until further analysis and bioassays.

3.3. Gas Chromatographic Analysis

Gas chromatographic–mass spectral analysis and chiral gas chromatography–mass spectrometry were performed according to the protocol described by Pham et al. (2023) [84].
Gas chromatographic–mass spectral analysis used a Shimadzu GCMS-QP2010 Ultra system equipped with an electron impact (EI) ionization source (70 eV) (Shimadzu Scientific Instruments, Columbia, MD, USA). The mass spectrometer operated over a scan range of 40–400 m/z at a scan rate of 3.0 scans/s. Separation was achieved on a ZB-5ms capillary column (60 m × 0.25 mm, 0.25 μm film thickness) (Phenomenex, Torrance, CA, USA), with helium as the carrier gas at a constant flow rate of 2.0 mL/min and a column head pressure of 208 kPa. The injector, detector, and interface were maintained at 260 °C. The oven temperature was programmed from 50 °C to 260 °C at a rate of 2 °C/min. The essential oil was diluted in dichloromethane (1% w/v), and 1.0 μL was injected with a split ratio of 1:24.4. Percentages were calculated based on peak integration values. No corrections were carried out. Retention indices (RIs) were determined using a homologous series of n-alkanes, and compound identification was based on comparison of RI values and mass spectral fragmentation patterns with those in reference databases [85,86,87].
Chiral gas chromatography–mass spectrometry was carried out using a Shimadzu GCMS-QP2010S system operating in electron impact (EI) mode at 70 eV (Shimadzu Scientific Instruments, Columbia, MD, USA). Separation was achieved on a Restek B-Dex 325 chiral capillary column (Restek Corp., Bellefonte, PA, USA). The oven temperature was programmed from 50 °C to 120 °C at a rate of 1.5 °C/min, followed by an increase from 120 °C to 200 °C at 2.0 °C/min. A 0.1 μL aliquot of a 5% (w/v) essential oil solution in dichloromethane was injected with a split ratio of 1:45. Compound identification was based on comparison of retention times and mass spectral fragmentation patterns with those of authentic standards (Sigma-Aldrich, Milwaukee, WI, USA). Enantiomeric percentages were calculated directly from peak areas without correction or standardization.

3.4. Preparation of Microemulsion Formulas

The microemulsions (MEs) were formulated using the emulsion phase inversion (EPI) technique, as described by Giang et al. (2024) [88]. The essential oil (3%, v/v), 2-propanol (1%, v/v), and MCT oil (1%, v/v) were sequentially mixed and stirred for 15 min using a magnetic stirrer (H3770-HS, Benchmark, Sayreville, NJ, USA). Polysorbate 80 (10% v/v) was then added, followed by 30 min of stirring. Distilled water (85% v/v) was gradually introduced at 3 mL/min, and stirring continued until a transparent, homogeneous microemulsion (ME) formed. MEs were stored in transparent vials at 25 °C under a 12 h light/12 h dark cycle. Droplet size distribution was measured on Days 1 and 30 using dynamic light scattering (Zetasizer-Nano ZS, Malvern, UK).

3.5. Larvicidal Biassays

Larvicidal activities were performed as described by Van et al. (2025) [69]. Aedes spp. mosquitoes were continuously maintained at Duy Tan University, while egg rafts of Cx. Quinquefasciatus and Cx. fuscocephala were collected from domestic wastewater channels in Da Nang City. Eggs from all three mosquito species were hatched overnight in tap water; larvae were reared on cat food (Me O Tuna Adult Cat Dry Food), and the water was replaced daily. Adult mosquitoes were maintained on a 10% glucose solution and allowed to blood-feed on mice. All experiments were conducted under controlled conditions of 25 °C and 75 ± 5% relative humidity.
Essential oil (EO) solutions were prepared in ethanol (Merck) at concentrations of 100, 50, 25, 12.5, and 6.25 µg/mL, and 150 mL of each solution was transferred into 250 mL glass beakers. Subsequently, 25 third- and early fourth-instar larvae were transferred into beakers containing the test solution. Each concentration was tested in quadruplicate. Ethanol and permethrin served as negative and positive controls, respectively. Larval mortality was recorded after 24 and 48 h of exposure.

3.6. Repellency Bioassay

Female Ae. aegypti mosquitoes (4–5 days old), mated and starved for 24 h, were used in repellency assays under controlled laboratory conditions (25 ± 2 °C, 65–75% relative humidity). Mosquitoes were confined in 30 × 30 × 30 cm test cages.
Volunteers’ hands were washed with unscented soap, air-dried, and covered with plastic gloves, leaving a 30 cm2 window (5 × 6 cm) exposed on the dorsal side. Essential oil solutions were prepared in ethanol (Merck) at concentrations of 10%, 50%, and 100% (v/v). A 100 μL aliquot of each solution was applied to the exposed skin area and allowed to dry for 3 min. Ethanol served as the negative control, while 10% DEET in ethanol was used as the positive control.
For repellency testing, the treated hand was inserted into the mosquito cage for 5 min. Each concentration was tested in triplicate with a new cohort of mosquitoes per replicate. To assess protection duration, treated hands were exposed for 5 min at 15 min intervals until the first confirmed bite (defined as two bites during a single exposure or a second bite in the subsequent interval). Control hands were introduced before each trial to verify mosquito activity.
To ensure consistency, hands were held parallel to the vertical surface of the cage, as mosquitoes were observed to preferentially bite the underside when positioned perpendicularly. Complete protection time was recorded as the interval from application to the first confirmed biting event.

3.7. Fumigant Toxicity

Fumigant toxicity was evaluated following the protocol described by Van et al. (2025) [69]. Essential oil solutions were prepared in acetone at concentrations of 12.5%, 6.25%, 3.0%, 1.5%, 0.625%, and 0.15% (v/v). For each assay, a 1 × 3 cm strip of filter paper was impregnated with 10 µL of the test solution and suspended centrally in a 250 mL glass flask containing 15 non-blood-fed adult mosquitoes. Each concentration was tested in quadruplicate, with acetone alone used as the negative control. Mortality was recorded at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, and 24 h post exposure. Mosquitoes were considered dead if they failed to respond to a gentle agitation of the flask.

3.8. Molluscicidal Activity

Snail species collection and molluscicidal activity were performed as described by Luu et al. (2023) [57] and Pham et al. (2023) [84]. Snail individuals were collected from a natural environment, acclimatized to laboratory conditions (25 °C, 70 ± 5% RH) for 48 h and fed on leaves of Lactuca sativa. After the acclimatization period, healthy snails were used for the experiment. The essential oil was dissolved in ethanol to obtain a 1% (w/v) stock solution, and different volumes of the stock solution were dissolved in beakers containing 150 mL of distilled water to obtain a range of concentrations of 100, 50, 25, 12.5 and 6.25 µg/mL. Each concentration was repeated 4 times, 5 snails for each replication. After 24 h of exposure, the number of dead snails was recorded, and the test solution in the beakers was replaced with fresh distilled water, and the experiment was continued for another 24 h. At 48 h of exposure, the number of dead snails was recorded.

3.9. AChE Inhibitory Activity Assay

The protocol for assessing AChE inhibitory activity was performed as described by Ellman et al. (1961) [89]. Test samples, including essential oils and pure compounds, were initially dissolved in 100% dimethyl sulfoxide (DMSO) and subsequently diluted with deionized distilled water to obtain concentrations of 500, 100, 20, and 4 μg/mL. Each assay well contained 140 μL of phosphate buffer (pH 8.0), 20 μL of the test solution, and 20 μL of acetylcholinesterase (AChE) from electric eel (0.25 IU/mL), followed by incubation at 25 °C for 15 min. Subsequently, 10 μL of dithiobisnitrobenzoic acid (DTNB, 2.5 mM) and 10 μL of acetylthiocholine iodide (ACTI, 2.5 mM) were added, and the reaction was incubated for an additional 10 min at 25 °C. Absorbance was recorded at 405 nm. Galantamine served as the positive control, while the negative control lacked test samples. All assays were performed in triplicate.

3.10. Antimicrobial Activity

Antimicrobial activity testing protocols were performed as described by Luu-dam et al. (2023) [83]. The antimicrobial properties of the tested essential oils were evaluated using a serial dilution technique across multiple concentrations. Essential oils were initially dissolved in dimethyl sulfoxide (DMSO) and then serially diluted to yield final concentrations of 256, 128, 64, 32, 16, 4, and 2 µg/mL, with each concentration tested in triplicate. Microbial suspensions were adjusted to a final density of 2 × 105 CFU/mL. The antimicrobial assays were conducted in sterile 96-well microtiter plates. A volume of 5.12 µL of each test solution (a stock concentration of 10 mg/mL) was transferred to the first well containing 100 µL of LB medium and then subjected to two-fold serial dilutions using 50 µL of medium per well, ultimately achieving a minimum test concentration of 2 µg/mL. Subsequently, 50 µL of microbial inoculum (2 × 105 CFU/mL) was added to each well, and the plates were incubated at 37 °C for 24 h. Following incubation, absorbance at 650 nm was recorded using a microplate reader (Epoch, BioTek Instruments Inc., Winooski, VT, USA) to determine microbial growth. Streptomycin, kanamycin, tetracycline, nystatin, and cycloheximide (all procured from Sigma-Aldrich) served as positive control agents.

3.11. Statistical Analysis

For the agglomerative hierarchical cluster (AHC) analysis, the essential oil compositions of 37 samples of C. odorata reported in the literature along with the three samples in this study were used. The 40 essential oil compositions were used as operational taxonomic units and the percent compositions of the nine most abundant components (α-pinene, sabinene, β-pinene, 3-carene, cis-sabinene hydrate, linalool, 4,8,12-trimethyltrideca-1,3,7,11-tetraene (DMNT), cyclohexene-3,4-diethenyl-3-methyl, geijerene, geranial, pregeijerene, α-cubebene, β-cubebene, (Z)-β-farnesene, α-copaene, cyperene, (E)-β-caryophyllene, anisole, trans-verbenol, dauca-5,8-diene, γ-muurolene, germacrene D, epi-cubebol, bicyclogermacrene, cubebol, γ-cadinene, δ-cadinene, α-cadinene, β-copaen-4α-ol, α-elemol, naphthalene and caryophyllene oxide) were used to examine the chemical relationships between the C. odorata essential oils. Euclidean distance was used to determine dissimilarity and clustering was defined using Ward’s method. Principal component analysis (PCA) was carried out to provide a visual verification of the chemical relationships between the C. odorata essential oil samples using the major components (as above) as variables with a Pearson correlation matrix. The AHC and PCA were carried out using XLSTAT Premium v. 2018.1.1.62926 (Addinsoft, Paris, France).

4. Conclusions

The essential oils extracted from C. odorata collected in three central provinces of Vietnam exhibited highly similar chemical profiles, predominantly comprising α-pinene, geigerene, germacrene D, and (E)-β-caryophyllene. This particular chemotype demonstrated notable insecticidal, acetylcholinesterase inhibitory, and antimicrobial activities. These findings indicate that C. odorata holds considerable potential as a natural source for the development of essential oil-based biopesticides. Further investigations on additional chemotypes are warranted to identify those with the most potent pesticidal properties.

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/molecules30173602/s1, Table S1: A review of the literature on the chemical composition of Chromolaena odorata essential oil.

Author Contributions

Conceptualization: H.H.N. and W.N.S.; Methodology: H.H.N.; Formal Analysis: H.H.N. and W.N.S.; Investigation: H.V.V., T.T.V., P.S., T.T.N., T.T.-T.L., A.T.-G.N. and H.T.V.; Writing—Original Draft Preparation: H.H.N.; Writing—Review and Editing: W.N.S.; Resources: H.H.N.; Supervision: H.H.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

This study was approved by the Duy Tan University Medical–Biological Research Ethics Council, Number DTU/REC2020/NHH02 and DTU/REC2024/NHH15.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data will be made available on request.

Acknowledgments

P.S. and W.N.S. participated in this work as part of the activities of the Aromatic Plant Research Center (APRC, https://aromaticplant.org/, accessed on 31 July 2023).

Conflicts of Interest

The authors declare no conflicts of interest.

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Molecules 30 03602 g001
Figure 1. Dendrogram based on agglomerative hierarchical cluster analysis of chemical compositions of Chromolaena odorata essential oils. Principal component analysis of chemical compositions of Chromolaena odorata essential oils. Details on the components, full chemical composition, and collection locations of the essential oil samples corresponding to codes O1 to O40 are available in Supplementary Material Table S1.
Figure 1. Dendrogram based on agglomerative hierarchical cluster analysis of chemical compositions of Chromolaena odorata essential oils. Principal component analysis of chemical compositions of Chromolaena odorata essential oils. Details on the components, full chemical composition, and collection locations of the essential oil samples corresponding to codes O1 to O40 are available in Supplementary Material Table S1.
Molecules 30 03602 g001
Molecules 30 03602 g002
Figure 2. Principal component analysis of chemical compositions of C. odorata essential oils. O4: [27]; O5: [28]; O6: [29]; O7: [30]; O8: [31]; O9: [4]; O10: [32]; O11: [32]; O12: [3]; O13: [33]; O14: [33]; O15–O22: [34]; O23–O29: [35]; O30: [36]; O31: [37]; O32–O36: [38]; O37: [39]; O38–O39: [40]; and O40: [41]. Details on the components, full chemical composition, and collection locations of the essential oil samples corresponding to codes O1 to O40 are available in Supplementary Material Table S1.
Figure 2. Principal component analysis of chemical compositions of C. odorata essential oils. O4: [27]; O5: [28]; O6: [29]; O7: [30]; O8: [31]; O9: [4]; O10: [32]; O11: [32]; O12: [3]; O13: [33]; O14: [33]; O15–O22: [34]; O23–O29: [35]; O30: [36]; O31: [37]; O32–O36: [38]; O37: [39]; O38–O39: [40]; and O40: [41]. Details on the components, full chemical composition, and collection locations of the essential oil samples corresponding to codes O1 to O40 are available in Supplementary Material Table S1.
Molecules 30 03602 g002
Molecules 30 03602 g003
Figure 3. Dynamic light scattering (DLS) traces of microemulsions (MEs) at different timepoints (t1 and t30 days).
Figure 3. Dynamic light scattering (DLS) traces of microemulsions (MEs) at different timepoints (t1 and t30 days).
Molecules 30 03602 g003
Molecules 30 03602 g004
Figure 4. Mortality rate (%) of mosquito larvae at different concentrations of samples O1, O2, O3 and MO1 after 24 h of exposure, with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Aedes aegypti. (B) Aedes albopictus. (C) Culex quinquefasciatus. (D) Culex fuscocephala.
Figure 4. Mortality rate (%) of mosquito larvae at different concentrations of samples O1, O2, O3 and MO1 after 24 h of exposure, with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Aedes aegypti. (B) Aedes albopictus. (C) Culex quinquefasciatus. (D) Culex fuscocephala.
Molecules 30 03602 g004
Molecules 30 03602 g005
Figure 5. Mortality rate (%) of mosquito larvae at different concentrations of samples O1, O2, O3 and MO1 after 48 h of exposure, with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Aedes aegypti. (B) Aedes albopictus. (C) Culex quinquefasciatus. (D) Culex fuscocephala.
Figure 5. Mortality rate (%) of mosquito larvae at different concentrations of samples O1, O2, O3 and MO1 after 48 h of exposure, with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Aedes aegypti. (B) Aedes albopictus. (C) Culex quinquefasciatus. (D) Culex fuscocephala.
Molecules 30 03602 g005
Molecules 30 03602 g006
Figure 6. Repellent efficacy (mean ± SD) of Chromolaena odorata essential oils (O1 and O3) and DEET against Aedes aegypti. Bars with the same letters are not significantly different (p > 0.05, ANOVA followed by Tukey’s test).
Figure 6. Repellent efficacy (mean ± SD) of Chromolaena odorata essential oils (O1 and O3) and DEET against Aedes aegypti. Bars with the same letters are not significantly different (p > 0.05, ANOVA followed by Tukey’s test).
Molecules 30 03602 g006
Molecules 30 03602 g007
Figure 7. Mortality rate (%) of snails at different concentrations of samples O1, O2, O3, and MO1 with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Physa acuta. (B) Indoplanorbis exustus. (C) Pomacea canaliculata.
Figure 7. Mortality rate (%) of snails at different concentrations of samples O1, O2, O3, and MO1 with mean ± SE. Values followed by the same letter (a–c) at each concentration are not statistically different at p < 0.05 as measured by Tukey’s test. (A) Physa acuta. (B) Indoplanorbis exustus. (C) Pomacea canaliculata.
Molecules 30 03602 g007
Table 1. Chemical composition of Chromolaena odorata essential oil.
Table 1. Chemical composition of Chromolaena odorata essential oil.
RIcalcRIdbCompound%
O1O2O3
927927α-Thujenetr0.090.09
935933α-Pinene11.4716.0819.24
950950Camphenetrtr0.05
974972Sabinene0.941.261.51
980978β-Pinene3.955.997.50
991991Myrcene0.670.650.89
10261025p-Cymenetr0.080.15
10311030Limonene0.730.650.73
10371035(Z)-β-Ocimene0.130.130.13
10471046(E)-β-Ocimene1.000.941.08
10591058γ-Terpinenetrtr0.09
1135-iso-Geijerene1.401.211.07
11451143Geijerene10.559.718.96
12861286Cogeijerene0.450.440.38
12951289Pregeijerene0.520.480.40
13331335Bicycloelemene0.130.12tr
13371336δ-Elemene0.320.350.30
13481348α-Cubebene0.140.10tr
13781377α-Copaene5.264.454.02
13851382β-Bourbonene0.170.300.19
13891387β-Cubebene0.160.100.06
13911390trans-β-Elemene1.741.391.30
14221418(E)-β-Caryophyllene11.2410.869.56
14311433β-Copaene0.530.470.48
14351431Dictamnol1.561.942.15
14421438iso-Dictamnol0.350.190.20
14501453trans-Muurola-3,5-diene0.200.150.16
14571454α-Humulene3.222.972.97
14611458allo-Aromadendrenetr0.100.08
14731473trans-Cadina-1(6),4-dienetr0.250.26
14781478γ-Muurolene0.640.720.67
14841483Germacrene D15.1213.4911.67
14931492trans-Muurola-4(14),5-diene0.620.390.43
14971497Bicyclogermacrene2.422.101.72
15001500α-Muurolene0.960.780.75
15071504(E,E)-α-Farnesenetr0.15tr
15091508β-Bisabolene0.190.210.12
15141514γ-Cadinene0.540.320.36
15161515Cubebol0.41tr0.22
15211520δ-Cadinene5.734.384.42
15231527trans-Calamenene0.730.470.71
15251526Zonarene0.20trtr
15331533trans-Cadina-1,4-diene0.13trtr
15421541α-Calacorene0.620.560.60
15501549α-Elemol0.52trtr
15521551iso-Caryophyllene oxide0.410.450.43
15591560Germacrene B0.410.460.48
15631562(E)-Nerolidol0.340.250.32
15791578Spathulenol0.760.730.74
15841587Caryophyllene oxide5.024.405.33
15901592Globuloltrtr0.25
15951594Viridiflorol0.350.39tr
16101611Humulene epoxide II1.000.810.99
16171618α-Corocalene0.240.13tr
16221625Junenol0.220.250.12
162816281-epi-Cubenol0.100.480.35
16331629iso-Spathulenol0.26tr-
16381644allo-Aromadendrene epoxide-0.350.38
16431643τ-Cadinol0.540.420.44
16451645τ-Muurolol0.440.430.43
16471651α-Muurolol (=δ-Cadinol)0.22trtr
16501647cis-Guaia-3,9-dien-11-ol0.370.500.33
16561655α-Cadinol1.371.131.05
16741676Mustakone0.250.360.32
17161715Pentadecanal0.180.270.33
21082109Phytol1.091.391.08
Monoterpene hydrocarbons18.8925.8731.46
Oxygenated monoterpenoids0.000.000.00
Sesquiterpene hydrocarbons51.6645.7741.31
Oxygenated sesquiterpenoids12.5810.9511.70
Diterpenoids1.091.391.08
Other15.0114.2413.49
Total identified99.2398.2299.04
RIcalc = retention index determined with respect to a homologous series of n-alkanes on a ZB-5ms column. RIdb = reference retention index from the databases. tr = trace (<0.05%). Major components are highlighted in bold.
Table 2. Th enantiomeric distribution of monoterpenes in Chromolaena odorata essential oils and other members of the Asteraceae reported in the literature.
Table 2. Th enantiomeric distribution of monoterpenes in Chromolaena odorata essential oils and other members of the Asteraceae reported in the literature.
CompoundRTdbRTexpO1O2O3A.l.A.a.A.m.o.E.n.
(−)-α-Pinene15.9215.4754.558.354.850.6–88.099.3–99.472.8–87.359.5–90.6
(+)-α-Pinene16.4015.9945.541.745.212.0–49.40.6–0.712.7–27.29.4–41.5
(+)-Sabinene19.7419.7663.264.260.813.9–79.448.2–53.711.8–56.10.0–25.6
(−)-Sabinene20.6020.7936.835.839.220.6–86.146.3–51.843.9–88.274.4–100.0
(+)-β-Pinene20.2720.1095.896.996.72.5–25.812.1–13.51.1–18.80.4–10.4
(−)-β-Pinene20.6220.984.23.13.374.2–97.586.5–87.981.2–98.989.6–99.6
(−)-Limonene25.0625.4630.938.739.638.0–100.050.2–60.431.8–83.140.2–95.8
(+)-Limonene25.9926.2369.161.360.40.0–62.039.6–49.816.9–68.24.2–59.8
A.l.: Artemisia ludoviciana Nutt. A.a.: Ambrosia acanthicarpa Hook. [42]. A.m.o.: Achillea millefolium L. var. occidentalis DC. [43]. E.n.: Ericameria nauseosa (Pursh) G.L.Nesom & G.I.Baird [44].
Table 3. Larvicidal activity of Chromolaena odorata essential oil and its microemulsion at 24 h exposure.
Table 3. Larvicidal activity of Chromolaena odorata essential oil and its microemulsion at 24 h exposure.
Essential OilLC50 (95% Limits)LC90 (95% Limits)χ2p
Aedes aegypti
O343.53 (40.30–46.90)68.96 (62.36–79.21)4.460.216
O253.46 (50.31–57.5871.26 (65.51–80.58)2.920.404
O152.99 (49.58–57.25)73.42 (67.43–82.42)7.100.069
MO132.43 (28.68–36.79)101.93 (83.00–133.89)6.620.085
Aedes albopictus
O353.42 (49.67–57.60)83.71 (75.09–97.99)2.070.557
O269.87 (63.94–76.81)127.60 (110.95–155.54)0.460.927
O144.08 (41.30–47.11)61.89 (57.61–67.78)1.590.663
MO129.81 (26.48–33.62)87.62 (72.41–112.62)8.110.044
Culex quinquefasciatus
O344.34 (40.58–48.50)83.06 (73.08–98.67)14.940.002
O244.31 (41.08–47.85)72.42 (65.20–83.30)3.780.287
O127.25 (24.95–29.74)52.65 (46.73–61.25)7.350.061
MO1NtNtNtNt
Culex fuscocephala
O331.97 (29.72–34.93)41.69 (38.13–47.16)3.560.313
O226.41 (24.31–28.89)41.26 (37.54–46.57)4.950.176
O111.73 (10.60–12.92)24.55 (21.40–29.53)0.910.823
MO111.16 (10.12–12.30)23.95 (20.87–28.61)2.140.710
MCO1: Microemulsion of CO1 essential oil sample. Nt: not tested.
Table 4. Larvicidal activity of Chromolaena odorata essential oil and its microemulsion at 48 h exposure.
Table 4. Larvicidal activity of Chromolaena odorata essential oil and its microemulsion at 48 h exposure.
Essential OilLC50 (95% Limits)LC90 (95% Limits)χ2p
Aedes aegypti
O345.23 (42.37–48.42)63.82 (59.27–70.19)1.680.642
O246.27 (42.96–49.75)72.12 (65.23–83.16)4.610.203
O141.05 (37.74–44.62)71.37 (63.63–83.23)5.170.160
MO128.54 (25.31–32.22)85.72 (70.68–110.50)7.550.056
Aedes albopictus
O338.89 (35.94–42.01)61.78 (55.88–70.63)1.970.578
O243.43 (39.73–47.52)81.75 (71.90–97.09)3.170.366
O123.04 (21.18–25.03)40.49 (36.08–47.23)2.230.527
MO127.08 (24.13–30.40)75.52 (63.11–95.53)10.590.014
Culex quinquefasciatus
O334.87 (32.12–37.87)58.93 (52.72–68.31)1.850.603
O239.07 (35.80–42.65)71.37 (63.17–83.91)7.550.056
O119.45 (18.06–20.93)30.66 (27.84–34.82)1.270.736
MO1NtNtNtNt
Culex fuscocephala
O329.76 (27.70–32.38)40.52 (37.09–45.63)5.310.257
O224.32 (22.34–26.63)38.83 (35.26–43.96)13.900.003
O110.53 (9.57–11.54)20.21 (17.79–24.02)0.900.825
MO19.84 (8.81–10.97)25.09 (21.45–30.68)13.110.011
MO1: Microemulsion of O1 essential oil sample. Nt: not tested.
Table 5. Knockdown time of Aedes aegypti mosquito exposed to Chromolaena odorata essential oil (O1).
Table 5. Knockdown time of Aedes aegypti mosquito exposed to Chromolaena odorata essential oil (O1).
Concentration (%)KT50 (m)KT90 (m)χ2p
2531.32 (27.60–35.16)63.42 (54.97–76.54)14.080.080
12.540.76 (35.51–46.10)98.86 (85.27–119.11)19.710.011
6.2554.87 (48.10–61.73)139.45 (120.57–167.47)22.990.003
3.0212.04 (186.54–243.40)824.78 (639.34–1170.59)8.790.360
1.5550.24 (456.51–697.94)2392.87 (1644.53–4098.97)4.020.855
1.0641.95 (534.11–811.29)2306.43 (1634.53–3770.21)13.060.110
0.51081.33 (873.80–1422.51)3607.33 (2500.65–6138.99)7.870.446
Table 6. Adulticidal activity of Chromolaena odorata essential oil (O1) on Aedes aegypti.
Table 6. Adulticidal activity of Chromolaena odorata essential oil (O1) on Aedes aegypti.
Time (min)LC50 (%)LC90 (%)χ2p
15106.03 (47.59–641.77)1469.91 (320.34–54115.90)3.720.590
3040.27 (26.48–81.72)314.51 (134.50–1512.64)3.730.590
608.64 (7.35–10.28)28.87 (22.17–41.64)5.940.312
904.68 (4.05–5.43)12.95 (10.49–17.16)9.910.078
1203.59 (3.15–4.09)8.08 (6.75–10.31)18.230.003
1802.69 (2.39–3.05)5.72 (4.82–7.25)17.770.003
2402.36 (2.07–2.69)5.57 (4.62–7.19)11.800.038
3001.95 (1.71–2.23)4.88 (4.02–6.38)10.500.062
3601.85 (1.63–2.12)4.63 (3.81–6.06)8.710.121
14400.34 (0.19–0.47)1.44 (1.13–2.08)3.420.636
Table 7. Molluscicidal activity of Chromolaena odorata essential oils (µg/mL).
Table 7. Molluscicidal activity of Chromolaena odorata essential oils (µg/mL).
Essential OilLC50 (95% Limits)LC90 (95% Limits)χ2p
Physa acuta
O36.89 (5.33–8.84)17.30 (12.72–29.43)5.750.331
O27.16 (5.62–9.07)16.26 (12.21–26.90)2.340.800
O13.82 (3.09–4.71)6.95 (5.47–11.13)0.570.989
CuSO4 (positive control)0.66 (0.55–0.80)0.85 (0.72–1.17)0.000.998
Indoplanorbis exustus
O326.97 (20.97–35.00)68.70 (49.60–123.03)1.770.779
O238.57 (29.97–50.74)98.63 (69.98–188.00)5.730.220
O121.88 (18.01–26.24)35.22 (28.81–53.59)1.120.878
MO122.47 (17.41–28.90)55.14 (40.29–98.39)0.700.872
CuSO4 (positive control)0.28 (0.23–0.33)0.43 (0.35–0.64)0.36180.948
Pomacea canaliculata
O354.38 (43.49–69.87)112.15 (83.46–207.92)11.400.022
O239.50 (31.47–50.12)83.49 (62.79–143.75)3.030.552
O125.80 (21.75–30.90)38.82 (32.04–64.33)1.790.774
MO130.06 (24.64–49.72)49.72 (41.08–66.80)7.150.128
Positive control (tea saponin)24.78 (23.26–26.72)32.62 (29.98–37.10)0.13010.988
Table 8. Acetylcholinesterase inhibitory activity of Chromolaena odorata essential oil (O1).
Table 8. Acetylcholinesterase inhibitory activity of Chromolaena odorata essential oil (O1).
Concentration (µg/mL)O1Concentration (µg/mL)Galanthamine
Inhibition (%)SDInhibition (%)SD
50091.722.771091.071.31
10059.481.54256.561.69
2025.381.150.421.830.93
48.930.620.089.070.42
IC5070.85 ± 5.47IC501.70 ± 0.12
Table 9. Antimicrobial activity of Chromolaena odorata essential oil.
Table 9. Antimicrobial activity of Chromolaena odorata essential oil.
MicroorganismEssential Oil (µg/mL)Positive Control (µg/mL)
O1O2O3StreptomycinCyclohexamide
MICIC50MICIC50MICIC50MICIC50MICIC50
Enterococcus faecalis
ATCC299212		329.34 ± 1.4620.67 ± 0.01165.34 ± 1.3225650.34 ± 2.32NtNt
Staphylococcus aureus
ATCC25923		6419.45 ± 2.1320.54 ± 0.023212.45 ± 0.0525645.24 ± 1.36NtNt
Bacillus cereus ATCC145796421.25 ± 0.2383.17 ± 0.78329.45 ± 0.1712820.45 ± 0.39NtNt
Escherichia coli
ATCC25922		12842.56 ± 2.5620.53 ± 0.45329.76 ± 1.32329.45 ± 0.35NtNt
Pseudomonas aeruginosa ATCC27853NaNaNaNaNaNa25664.67 ± 1.89NtNt
Salmonella enterica ATCC130766440.34 ± 3.2183.23 ± 0.06329.24 ± 0.7412845.67 ± 2.30NtNt
Candida albicans ATCC102313220.45 ± 1.0420.67 ± 0.021329.27 ± 0.96NtNt3210.46 ± 0.32
Na: not active; Nt: not tested.
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Vo, H.V.; Satyal, P.; Vo, T.T.; Le, T.T.-T.; Nguyen, A.T.-G.; Vu, H.T.; Nguyen, T.T.; Nguyen, H.H.; Setzer, W.N. Chemical Composition and Biological Activities of Chromolaena odorata (L.) R.M.King & H.Rob. Essential Oils from Central Vietnam. Molecules 2025, 30, 3602. https://doi.org/10.3390/molecules30173602

AMA Style

Vo HV, Satyal P, Vo TT, Le TT-T, Nguyen AT-G, Vu HT, Nguyen TT, Nguyen HH, Setzer WN. Chemical Composition and Biological Activities of Chromolaena odorata (L.) R.M.King & H.Rob. Essential Oils from Central Vietnam. Molecules. 2025; 30(17):3602. https://doi.org/10.3390/molecules30173602

Chicago/Turabian Style

Vo, Hoa Van, Prabodh Satyal, Thuong Thanh Vo, Truc Thi-Thanh Le, An Thi-Giang Nguyen, Hien Thi Vu, Trung Thanh Nguyen, Hung Huy Nguyen, and William N. Setzer. 2025. "Chemical Composition and Biological Activities of Chromolaena odorata (L.) R.M.King & H.Rob. Essential Oils from Central Vietnam" Molecules 30, no. 17: 3602. https://doi.org/10.3390/molecules30173602

APA Style

Vo, H. V., Satyal, P., Vo, T. T., Le, T. T.-T., Nguyen, A. T.-G., Vu, H. T., Nguyen, T. T., Nguyen, H. H., & Setzer, W. N. (2025). Chemical Composition and Biological Activities of Chromolaena odorata (L.) R.M.King & H.Rob. Essential Oils from Central Vietnam. Molecules, 30(17), 3602. https://doi.org/10.3390/molecules30173602

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