Research of Bioactive Substances in Plant Extracts II

A special issue of Plants (ISSN 2223-7747). This special issue belongs to the section "Phytochemistry".

Deadline for manuscript submissions: closed (20 March 2023) | Viewed by 39790

Special Issue Editors


E-Mail Website1 Website2
Guest Editor
Department of Sciences of Life and Environment, University of Cagliari, Monserrato, Cagliari, Italy
Interests: plant extracts; bioactive compounds; enzymes; enzyme inhibition; protein purification and characterization
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Plant natural compounds represent an ever-increasing topic of research interest. Most of them are bioactive molecules with a broad range of biological properties. These include anticancer, antimicrobial, antiviral, anti-amyloidogenic, anti-inflammatory, and other biological activities.

To exert their effect, they could bind to specific enzymes and modulate their activity. Due to the important role of enzymes in several diseases’ pathogenesis, they represent targets for therapeutic intervention strategies. Thus, discovery of enzyme modulators is an interesting research area in the biochemistry and drug design field. Several plant extracts or plant-derived compounds are already reported to be inhibitors of tyrosinase, cyclooxygenases, MAOs, cholinesterases, amylase, and glycosidase, which are involved in pigmentation, inflammation, Alzheimer’s disease or diabetes.

The aim of this Special Issue is to highlight the newest discoveries in plant extract products and focus attention on the beneficial biological effects of plant extracts or plant-isolated compounds; their potential application in disease treatment and health promotion will also be of particular interest.

Dr. Francesca Pintus
Dr. Celestino Santos-Buelga
Guest Editors

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Keywords

  • plants extracts
  • bioactive compounds
  • enzyme inhibition
  • essential oils
  • anti-inflammatory
  • antiviral activity
  • antimicrobial activity
  • pharmaceutical potential
  • health benefit

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Published Papers (15 papers)

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22 pages, 1765 KiB  
Article
The Antimicrobial Effects of Myrosinase Hydrolysis Products Derived from Glucosinolates Isolated from Lepidium draba
by Zoltán Polozsányi, Helena Galádová, Michal Kaliňák, Martin Jopčík, Barbora Kaliňáková, Albert Breier and Martin Šimkovič
Plants 2024, 13(7), 995; https://doi.org/10.3390/plants13070995 - 30 Mar 2024
Viewed by 932
Abstract
Lepidium draba (hoary cress) is a perennial plant belonging to the Brassicaceae family that produces two dominant glucosinolates (GLSs): glucoraphanin (GRN) and sinalbin (SBN). They represent the stored form, which is converted upon the myrosinase (Myr) hydrolysis activity to active compounds, mainly isothiocyanates [...] Read more.
Lepidium draba (hoary cress) is a perennial plant belonging to the Brassicaceae family that produces two dominant glucosinolates (GLSs): glucoraphanin (GRN) and sinalbin (SBN). They represent the stored form, which is converted upon the myrosinase (Myr) hydrolysis activity to active compounds, mainly isothiocyanates (ITCs) such as sulforaphane (SFN) or p-hydroxybenzyl isothiocyanate (pHBITC). Research on ITCs that have proven anticancer, antimicrobial, and chemoprotective properties is usually conducted with pure commercially available compounds. However, these are chemically reactive, making it difficult to use them directly for preventive purposes in dietary supplements. Efforts are currently being made to prepare dietary supplements enriched with GLS and/or Myr. In this study, we report a simple but efficient chromatographic procedure for the isolation and purification of GLSs from MeOH extract from hoary cress based on a combination of ion exchange and gel permeation chromatography on DEAE-Sephadex A-25 and Sephadex LH-20. To obtain the Myr required for efficient hydrolysis of GLSs into antibacterial ITCs, we developed a rapid method for its extraction from the seeds of Lepidium sativum (garden cress). The yields of GLSs were 22.9 ± 1.2 mg GRN (purity 96%) and 10.4 ± 1.1 mg SBN (purity 92%) from 1 g of dry plant material. Both purified GLSs were used as substrates for the Myr. Analysis of the composition of hydrolysis products (HPs) revealed differences in their hydrolysis rates and in the degree of conversion from GLSs to individual ITCs catalyzed by Myr. When GRNs were cleaved, SFNs were formed in an equimolar ratio, but the formation of pHBITCs was only half that of cleaved SBNs. The decrease in pHBITC content is due to its instability compared to SFN. While SFN is stable in aqueous media during the measurement, pHBITC undergoes non-enzymatic hydrolysis to p-hydroxybenzyl alcohol and thiocyanate ions. Testing of the antimicrobial effects of the HPs formed from GRN by Myr under premix or in situ conditions showed inhibition of the growth of model prokaryotic and eukaryotic microorganisms. This observation could serve as the jumping-off point for the design of a two-component mixture, based on purified GLSs and Myr that is, usable in food or the pharmaceutical industry in the future. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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10 pages, 2070 KiB  
Article
Plant Extracts Control In Vitro Growth of Disease-Causing Fungi in Chayote
by Edgar García-Ramírez, Adriana Contreras-Oliva, Josafhat Salinas-Ruiz, Gabriela Hernández-Ramírez, José Luis Spinoso-Castillo and Saira Itzel Colmenares Cuevas
Plants 2023, 12(9), 1800; https://doi.org/10.3390/plants12091800 - 27 Apr 2023
Cited by 3 | Viewed by 1978
Abstract
The use of agrochemicals has caused environmental problems and toxicity to humans, so natural alternatives for disease control during harvest and postharvest have been evaluated. The aim of this study was to evaluate cinnamon essential oil, neem oil, and black sapote fruit extract [...] Read more.
The use of agrochemicals has caused environmental problems and toxicity to humans, so natural alternatives for disease control during harvest and postharvest have been evaluated. The aim of this study was to evaluate cinnamon essential oil, neem oil, and black sapote fruit extract for in vitro inhibition of fungi isolated from chayote fruit. The extracts were applied at 300, 350, and 400 ppm in Petri dishes and the mycelial growth of Fusarium oxysporum, Fusarium solani, Goetrichum sp., and Phytophthora capsici was evaluated for 7 days, and the percentage of mycelial growth inhibition per day was calculated. Cinnamon oil showed a fungicidal effect at all concentrations. Neem oil at 400 ppm showed a 42.3% reduction in the growth of F. solani and 27.8% reduction in the growth of F. oxysporum, while at 350 ppm it inhibited the mycelial growth of Phytophthora capsici by 53.3% and of Goetrichum sp. by 20.9%; finally, the black sapote extract at 400 ppm inhibited 21.9–28.6% of the growth of all fungi. The growth of postharvest fungi on chayote fruit could be prevented or reduced by applying the plant extracts evaluated at adequate concentrations. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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11 pages, 1780 KiB  
Communication
Methoxyflavones from Black Ginger (Kaempferia parviflora Wall. ex Baker) and their Inhibitory Effect on Melanogenesis in B16F10 Mouse Melanoma Cells
by Chen Huo, Sullim Lee, Min Jeong Yoo, Bum Soo Lee, Yoon Seo Jang, Ho Kyong Kim, Seulah Lee, Han Yong Bae and Ki Hyun Kim
Plants 2023, 12(5), 1183; https://doi.org/10.3390/plants12051183 - 5 Mar 2023
Cited by 3 | Viewed by 3199
Abstract
Kaempferia parviflora Wall. ex Baker (Zingiberaceae), commonly known as Thai ginseng or black ginger, is a tropical medicinal plant in many regions. It has been traditionally used to treat various ailments, including ulcers, dysentery, gout, allergies, abscesses, and osteoarthritis. As part of our [...] Read more.
Kaempferia parviflora Wall. ex Baker (Zingiberaceae), commonly known as Thai ginseng or black ginger, is a tropical medicinal plant in many regions. It has been traditionally used to treat various ailments, including ulcers, dysentery, gout, allergies, abscesses, and osteoarthritis. As part of our ongoing phytochemical study aimed at discovering bioactive natural products, we investigated potential bioactive methoxyflavones from K. parviflora rhizomes. Phytochemical analysis aided by liquid chromatography–mass spectrometry (LC-MS) led to the isolation of six methoxyflavones (16) from the n-hexane fraction of the methanolic extract of K. parviflora rhizomes. The isolated compounds were structurally determined to be 3,7-dimethoxy-5-hydroxyflavone (1), 5-hydroxy-7-methoxyflavone (2), 7,4′-dimethylapigenin (3), 3,5,7-trimethoxyflavone (4), 3,7,4′-trimethylkaempferol (5), and 5-hydroxy-3,7,3′,4′-tetramethoxyflavone (6), based on NMR data and LC-MS analysis. All of the isolated compounds were evaluated for their anti-melanogenic activities. In the activity assay, 7,4′-dimethylapigenin (3) and 3,5,7-trimethoxyflavone (4) significantly inhibited tyrosinase activity and melanin content in IBMX-stimulated B16F10 cells. In addition, structure–activity relationship analysis revealed that the methoxy group at C-5 in methoxyflavones is key to their anti-melanogenic activity. This study experimentally demonstrated that K. parviflora rhizomes are rich in methoxyflavones and can be a valuable natural resource for anti-melanogenic compounds. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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13 pages, 2164 KiB  
Article
Phytochemical Investigation of Myrcianthes cisplatensis: Structural Characterization of New p-Coumaroyl Alkylphloroglucinols and Antimicrobial Evaluation against Staphylococcus aureus
by Francesca Guzzo, Elisabetta Buommino, Leslie Landrum, Rosita Russo, Francesca Lembo, Antonio Fiorentino and Brigida D’Abrosca
Plants 2023, 12(5), 1046; https://doi.org/10.3390/plants12051046 - 24 Feb 2023
Cited by 1 | Viewed by 1486
Abstract
Species of Myrtaceae Juss., the ninth largest family of flowering plants, are a valuable source of bioactive specialized metabolites. A leading position belongs to phloroglucinol derivatives, thanks to their unusual structural features and biological and pharmacological properties. Myrcianthes cisplatensis (Cambess.) O. Berg, a [...] Read more.
Species of Myrtaceae Juss., the ninth largest family of flowering plants, are a valuable source of bioactive specialized metabolites. A leading position belongs to phloroglucinol derivatives, thanks to their unusual structural features and biological and pharmacological properties. Myrcianthes cisplatensis (Cambess.) O. Berg, a common tree on the banks of rivers and streams of Uruguay, southern Brazil, and northern Argentina, with aromatic leaves, is known as a diuretic, febrifuge, tonic, and good remedy for lung and bronchial diseases. Despite knowledge about traditional use, few data on its phytochemical properties have been reported in the literature. The methanol extract of M. cisplatensis, grown in Arizona, USA, was first partitioned between dichloromethane and water and then with ethyl acetate. The enriched fractions were evaluated using a broth microdilution assay against Staphylococcus aureus ATCC 29213 and 43300 (methicillin-resistant S. aureus (MRSA)). The potential antimicrobial activity seemed to increase in the dichloromethane extract, with a MIC value of 16 µg/mL against both strains. Following a bio-guided approach, chromatographic techniques allowed for isolating three coumarin derivatives, namely endoperoxide G3, catechin, and quercitrin, and four new p-coumaroyl alkylphloroglucinol glucosides, named p-coumaroylmyrciacommulone A-D. Their structures were characterized through spectroscopic techniques: 2D-NMR experiments (HSQC, HMBC, and HSQC-TOCSY) and spectrometric analyses (HR-MS). The antimicrobial assessment of pure compounds against S. aureus ATCC 29213 and ATCC 43300 demonstrated the best activity for p-coumaroylmyrciacommulone C and D with the growth inhibition of 50% at 32 µg/mL against both strains of S. aureus. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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16 pages, 2362 KiB  
Article
Phenolic Profile, Antioxidant and DNA-Protective Capacity, and Microscopic Characters of Ailanthus altissima Aerial Substances
by Tsvetelina Andonova, Yordan Muhovski, Iliya Slavov, Radka Vrancheva, Vasil Georgiev, Elena Apostolova, Samir Naimov, Rumen Mladenov, Atanas Pavlov and Ivanka Dimitrova-Dyulgerova
Plants 2023, 12(4), 920; https://doi.org/10.3390/plants12040920 - 17 Feb 2023
Cited by 8 | Viewed by 1977
Abstract
Invasive species as sources of natural components are of increasing interest for scientific research. This is the case of Ailanthus altissima, which belongs to the top 100 of the most dangerous invasive plant species in Europe, and which is the subject of [...] Read more.
Invasive species as sources of natural components are of increasing interest for scientific research. This is the case of Ailanthus altissima, which belongs to the top 100 of the most dangerous invasive plant species in Europe, and which is the subject of the present study. The purpose of the research was to analyze the main phenolic compounds in the flowers, leaves, and stem bark of A. altissima and determine the DNA-protective and antioxidant potential of their ethanolic extracts. HPLC profiling revealed the presence of 6 flavonoids and 10 phenolic acids, of which 15 were found in flowers, 14 in leaves, and 11 in the stem bark. Rutin (5.68 mg/g dw in flowers), hesperidin (2.67 mg/g dw in leaves) and (+)-catechin (2.15 mg/g dw in stem bark) were the best-represented flavonoids. Rosmarinic (10.32 mg/g dw in leaves) and salicylic (6.19 mg/g dw in leaves) acids were predominant among phenolic acids. All plant extracts tested showed in vitro antioxidant activity (determined by DPPH, ABTS, FRAP, and CUPRAC assays) and DNA-protection capacity (assay with supercoiled plasmid DNA—pUC19). The highest antioxidant activity was recorded in the flower parts (in the range from 661 to 893 mmol TE/g dw), followed by the leaves. A DNA protective potential for A. altissima leaf and flower extracts has not been established to date. In addition, the main microscopic diagnostic features of studied plant substances were described, with data for the flower parts being reported for the first time. The present study proves that A. altissima could be a natural source of DNA protection and antioxidants. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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41 pages, 4575 KiB  
Article
Antibacterial Components and Modes of the Methanol-Phase Extract from Commelina communis Linn
by Yue Liu, Yingping Tang, Shunlin Ren and Lanming Chen
Plants 2023, 12(4), 890; https://doi.org/10.3390/plants12040890 - 16 Feb 2023
Cited by 3 | Viewed by 1950
Abstract
Infectious diseases caused by pathogenic bacteria severely threaten human health. Traditional Chinese herbs are potential sources of new or alternative medicine. In this study, we analyzed for the first time antibacterial substances in the methanol-phase extract from a traditional Chinese herb—Commelina communis [...] Read more.
Infectious diseases caused by pathogenic bacteria severely threaten human health. Traditional Chinese herbs are potential sources of new or alternative medicine. In this study, we analyzed for the first time antibacterial substances in the methanol-phase extract from a traditional Chinese herb—Commelina communis Linn—which showed an inhibition rate of 58.33% against 24 species of common pathogenic bacteria. The extract was further purified using preparative high-performance liquid chromatography (Prep-HPLC), which generated four single fragments (Fragments 1 to 4). The results revealed that Fragment 1 significantly increased bacterial cell surface hydrophobicity and membrane permeability and decreased membrane fluidity, showing disruptive effects on cell integrity of Gram-positive and Gram-negative bacteria, such as Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, and Salmonella enterica subsp., compared to the control groups (p < 0.05). In sum, 65 compounds with known functions in Fragment 1 were identified using liquid chromatography and mass spectrometry (LC-MS), of which quercetin-3-o-glucuronide was predominant (19.35%). Comparative transcriptomic analysis revealed multiple altered metabolic pathways mediated by Fragment 1, such as inhibited ABC transporters, ribosome, citrate cycle and oxidative phosphorylation, and upregulated nitrogen metabolism and purine metabolism, thereby resulting in the repressed bacterial growth and even death (p < 0.05). Overall, the results of this study demonstrate that Fragment 1 from C. communis Linn is a promising candidate against common pathogenic bacteria. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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16 pages, 1980 KiB  
Article
Regulatory Effects of Thai Rice By-Product Extracts from Oryza sativa L. cv. Bue Bang 3 CMU and Bue Bang 4 CMU on Melanin Production, Nitric Oxide Secretion, and Steroid 5α-Reductase Inhibition
by Warintorn Ruksiriwanich, Pichchapa Linsaenkart, Chiranan Khantham, Anurak Muangsanguan, Korawan Sringarm, Pensak Jantrawut, Chanakan Prom-u-thai, Sansanee Jamjod, Supapohn Yamuangmorn, Chaiwat Arjin, Pornchai Rachtanapun, Kittisak Jantanasakulwong, Yuthana Phimolsiripol, Francisco J. Barba, Sarana Rose Sommano, Romchat Chutoprapat and Korawinwich Boonpisuttinant
Plants 2023, 12(3), 653; https://doi.org/10.3390/plants12030653 - 2 Feb 2023
Cited by 1 | Viewed by 2951
Abstract
Alopecia and gray hair are common hair abnormalities affecting physical appearance and causing psychological problems. Chemical treatments partially restore hair disorders but have distressing side effects. Bioactive plant compounds constitute promising sources of potential medicinal substances instead of chemical agents, producing high side [...] Read more.
Alopecia and gray hair are common hair abnormalities affecting physical appearance and causing psychological problems. Chemical treatments partially restore hair disorders but have distressing side effects. Bioactive plant compounds constitute promising sources of potential medicinal substances instead of chemical agents, producing high side effects. In this study, we focused on the waste of local rice cultivars: Bue Bang 3 CMU (BB3CMU) and Bue Bang 4 CMU (BB4CMU) from the north of Thailand. The rice bran oil (RBO), defatted rice bran extract (DFRB), and rice husk (H) were determined for in vitro hair revitalization in melanin production, nitric oxide (NO) secretion, and steroid 5α-reductase inhibition. The results indicated that BB4CMU-RBO with high contents of iron, zinc, and free fatty acids showed a comparable induction of melanin production on melanocytes (130.18 ± 9.13% of control) to the standard drug theophylline with no significant difference (p > 0.05). This promising melanin induction could be related to activating the NO secretion pathway, with the NO secretion level at 1.43 ± 0.05 µM. In addition, BB4CMU-RBO illustrated a significant inhibitory effect on both steroid 5α-reductase genes (SRD5A) type 1 and type 2, which relates to its primary source of tocopherols. Hence, rice bran oil from the Thai rice variety BB4CMU could be applied as a promising hair revitalizing candidate, from natural resources, to help promote hair growth and re-pigmentation effects. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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25 pages, 6194 KiB  
Article
Novel Signposts on the Road from Natural Sources to Pharmaceutical Applications: A Combinative Approach between LC-DAD-MS and Offline LC-NMR for the Biochemical Characterization of Two Hypericum Species (H. montbretii and H. origanifolium)
by Stefania Sut, Stefano Dall’Acqua, Gokhan Zengin, Ismail Senkardes, Abdullahi Ibrahim Uba, Abdelhakim Bouyahya and Abdurrahman Aktumsek
Plants 2023, 12(3), 648; https://doi.org/10.3390/plants12030648 - 1 Feb 2023
Cited by 5 | Viewed by 1998
Abstract
The members of the genus Hypericum have great potential to develop functional uses in nutraceutical and pharmaceutical applications. With this in mind, we aimed to determine the chemical profiling and biological properties of different extracts (ethyl acetate, methanol and water) from two Hypericum [...] Read more.
The members of the genus Hypericum have great potential to develop functional uses in nutraceutical and pharmaceutical applications. With this in mind, we aimed to determine the chemical profiling and biological properties of different extracts (ethyl acetate, methanol and water) from two Hypericum species (H. montbretii and H. origanifolium). We combined two approaches (LC-DAD-MS and LC-NMR) to identify and quantify chemical compounds of the extracts. Antioxidant properties (free radical quenching, reducing power and metal chelating) and enzyme inhibitory effects (cholinesterase, tyrosinase, amylase and glucosidase) were determined as biological properties. The tested extracts were rich in caffeic acid derivatives and flavonoids, and among them, 3-caffeoyl quinic acid and myricetin-3-O-rhamnoside were found to be the main compounds. The total phenolic and flavonoid levels were determined to be 50.97–134.99 mg GAE/g and 9.87–82.63 mg RE/g, respectively. With the exception of metal chelating, the methanol and water extracts showed stronger antioxidant properties than the ethyl acetate extracts. However, different results were obtained for each enzyme inhibition assay, and in general, the ethyl acetate extracts present more enzyme-inhibiting properties than the water or methanol extracts. Results from chemical and biological analyses were combined using multivariate analysis, which allowed establishing relationships between composition and observed effects of the Hypericum extracts based on the extraction solvents. To gain more insights between chemical compounds and enzyme-inhibiting effects, we performed molecular docking analysis. We observed favorable interactions between certain compounds and the tested enzymes during our analysis, confirming the data obtained from the multivariate approach. In conclusion, the obtained results may shed light on the road from natural sources to functional applications, and the tested Hypericum species may be considered potential raw materials, with promising chemical constituents and biological activities. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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12 pages, 1789 KiB  
Article
LC-MS Analysis and Antifungal Activity of Turnera subulata Sm.
by Jacqueline Cosmo Andrade-Pinheiro, Celestina Elba Sobral de Souza, Daiany Alves Ribeiro, Andressa de Alencar Silva, Viviane Bezerra da Silva, Antonia Thassya Lucas dos Santos, Victor Juno Alencar Fonseca, Delmacia Gonçalves de Macêdo, Rafael Pereira da Cruz, José Weverton Almeida-Bezerra, Antonio Júdson Targino Machado, Thiago Sampaio de Freitas, Edy Sousa de Brito, Paulo Riceli Vasconcelos Ribeiro, José Galberto Martins da Costa, Henrique Douglas Melo Coutinho, Grażyna Kowalska, Rafał Rowiński, Radosław Kowalski and Maria Flaviana Bezerra Morais-Braga
Plants 2023, 12(2), 415; https://doi.org/10.3390/plants12020415 - 16 Jan 2023
Cited by 3 | Viewed by 2452
Abstract
Fungi of the Candida genus are responsible for invasive candidiasis, which affects people all over the world and has high mortality rates. This is due to their virulence factors, which give them great resistance and pathogenicity. In addition, the emergence of multidrug-resistant strains [...] Read more.
Fungi of the Candida genus are responsible for invasive candidiasis, which affects people all over the world and has high mortality rates. This is due to their virulence factors, which give them great resistance and pathogenicity. In addition, the emergence of multidrug-resistant strains makes it difficult to treat these infections. In this way, natural products have emerged as an alternative to standard drugs, where plants known for their medicinal properties such as Turnera subulata become attractive to research. The present work aimed to analyze the ethanol extract of Turnera subulata leaves against standard strains of Candida albicans, Candida krusei and Candida tropicalis using broth microdilution techniques. The identification of the compounds in T. subulata leaves by LC-MS revealed the presence of a wide variety of substances such as carboxylic acids and terpenes, with flavonoids and fatty acids being more evident. The antifungal assays showed that the extract was not able to inhibit the growth of the tested strains at concentrations with a clinical relevance. However, at higher concentrations, it was able to inhibit the fungal dimorphism of C. albicans and C. tropicalis. It is possible that the T. subulata extract has potential as an inhibitor of fungal virulence factors without affecting the cell viability. Further research should be carried out in order to assess its inhibitory potential for other fungal virulence factors. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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8 pages, 1007 KiB  
Communication
Kukoamine B from Lycii Radicis Cortex Protects Human Keratinocyte HaCaT Cells through Covalent Modification by Trans-2-Nonenal
by Hye Mi Kim, Jae Yong Kim, Ji Hoon Kim and Chul Young Kim
Plants 2023, 12(1), 163; https://doi.org/10.3390/plants12010163 - 29 Dec 2022
Cited by 1 | Viewed by 1514
Abstract
The unsaturated aldehyde trans-2-nonenal is known to be generated by lipid peroxidation at the surface of the skin in an aging-related manner and has harmful effects on keratinocytes in the skin. In this study, the protective effect of a Lycii Radicis Cortex [...] Read more.
The unsaturated aldehyde trans-2-nonenal is known to be generated by lipid peroxidation at the surface of the skin in an aging-related manner and has harmful effects on keratinocytes in the skin. In this study, the protective effect of a Lycii Radicis Cortex (LRC) extract against trans-2-nonenal-induced cell damage on human keratinocyte cell lines (HaCaT) was investigated. Notably, treatment with the LRC extract resulted in an increase in cell survival, while trans-2-nonenal decreased the viability of HaCaT cells. For identification of interaction between the LRC extract and trans-2-nonenal, this mixture was incubated in simulated physiological conditions, showing a strong decrease in the amount of trans-2-nonenal by the LRC extract. Subsequent LC-ESI-MS analysis revealed that kukoamine B (KB) formed Schiff base-derived pyridinium adducts with trans-2-nonenal. Thus, these results suggest that KB could be a potential agent that may protect HaCaT cells by forming new products with trans-2-nonenal. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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11 pages, 1864 KiB  
Communication
Phytochemical Investigation of Marker Compounds from Indigenous Korean Salix Species and Their Antimicrobial Effects
by Yoon Seo Jang, Da Eun Lee, Joo-Hyun Hong, Kyung Ah Kim, Bora Kim, Yeo Rang Cho, Moon-Jin Ra, Sang-Mi Jung, Jeong-Nam Yu, Seongpil An and Ki Hyun Kim
Plants 2023, 12(1), 104; https://doi.org/10.3390/plants12010104 - 26 Dec 2022
Cited by 3 | Viewed by 2282
Abstract
Salix species, including willow trees, are distributed in the temperate regions of Asian countries, including South Korea. Willow trees are used to treat pain and inflammatory diseases. Due to the medicinal properties of willow trees, pharmacological studies of other Salix spp. have gained [...] Read more.
Salix species, including willow trees, are distributed in the temperate regions of Asian countries, including South Korea. Willow trees are used to treat pain and inflammatory diseases. Due to the medicinal properties of willow trees, pharmacological studies of other Salix spp. have gained attention; however, only a few studies have investigated the phytochemicals of these species. As part of our ongoing natural product research to identify bioactive phytochemicals and elucidate their chemical structures from natural resources, we investigated the marker compounds from indigenous Korean Salix species, namely, Salix triandra, S. chaenomeloides, S. gracilistyla, S. koriyanagi, S. koreensis, S. pseudolasiogyne, S. caprea, and S. rorida. The ethanolic extract of each Salix sp. was investigated using high-performance liquid chromatography combined with thin-layer chromatography and liquid chromatography–mass spectrometry-based analysis, and marker compounds of each Salix sp. were isolated. The chemical structures of the marker compounds (1–8), 3-(4-hydroxyphenyl)propyl β-D-glucopyranoside (1), 2-O-acetylsalicin (2), 1-O-p-coumaroyl glucoside (3), picein (4), isograndidentatin B (5), 2′-O-acetylsalicortin (6), dihydromyricetin (7), and salicin (8) were elucidated via nuclear magnetic resonance spectroscopy and high-resolution liquid chromatography–mass spectrometry using ultrahigh-performance liquid chromatography coupled with a G6545B Q-TOF MS system with a dual electrospray ionization source. The identified marker compounds 1–8 were examined for their antimicrobial effects against plant pathogenic fungi and bacteria. Dihydromyricetin (7) exhibited antibacterial activity against Staphylococcus aureus, inducing 32.4% inhibition at a final concentration of 125 μg/mL with an MIC50 value of 250 μg/mL. Overall, this study isolated the marker compounds of S. triandra, S. chaenomeloides, S. gracilistyla, S. koriyanagi, S. koreensis, S. pseudolasiogyne, S. caprea, and S. rorida and identified the anti-Staphylococcus aureus bacterial compound dihydromyricetin. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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23 pages, 2972 KiB  
Article
Characterization of Neochloris oleoabundans under Different Cultivation Modes and First Results on Bioactivity of Its Extracts against HCoV-229E Virus
by Costanza Baldisserotto, Valentina Gentili, Roberta Rizzo, Chiara Di Donna, Luna Ardondi, Annalisa Maietti and Simonetta Pancaldi
Plants 2023, 12(1), 26; https://doi.org/10.3390/plants12010026 - 21 Dec 2022
Cited by 3 | Viewed by 2037
Abstract
Microalgae are proposed in several biotechnological fields because of their ability to produce biomass enriched in high-value compounds according to cultivation conditions. Regarding the health sector, an emerging area focuses on natural products exploitable against viruses. This work deals with the characterization of [...] Read more.
Microalgae are proposed in several biotechnological fields because of their ability to produce biomass enriched in high-value compounds according to cultivation conditions. Regarding the health sector, an emerging area focuses on natural products exploitable against viruses. This work deals with the characterization of the green microalga Neochloris oleoabundans cultivated under autotrophic and mixotrophic conditions as a source of whole aqueous extracts, tested as antivirals against HCoV-229E (Coronaviridae family). Glucose was employed for mixotrophic cultures. Growth and maximum quantum yield of photosystem II were monitored for both cultivations. Algae extracts for antiviral tests were prepared using cultures harvested at the early stationary phase of growth. Biochemical and morphological analyses of algae indicated a different content of the most important classes of bioactive compounds with antiviral properties (lipids, exo-polysaccharides, and total phenolics, proteins and pigments). To clarify which phase of HCoV-229E infection on MRC-5 fibroblast cells was affected by N. oleoabundans extracts, four conditions were tested. Extracts gave excellent results, mainly against the first steps of virus infection. Notwithstanding the biochemical profile of algae/extracts deserves further investigation, the antiviral effect may have been mainly promoted by the combination of proteins/pigments/phenolics for the extract derived from autotrophic cultures and of proteins/acidic exo-polysaccharides/lipids in the case of mixotrophic ones. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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14 pages, 1609 KiB  
Article
Guava (Psidium guajava L.) Leaf Extract as Bioactive Substances for Anti-Androgen and Antioxidant Activities
by Warintorn Ruksiriwanich, Chiranan Khantham, Anurak Muangsanguan, Yuthana Phimolsiripol, Francisco J. Barba, Korawan Sringarm, Pornchai Rachtanapun, Kittisak Jantanasakulwong, Pensak Jantrawut, Chuda Chittasupho, Romchat Chutoprapat, Korawinwich Boonpisuttinant and Sarana Rose Sommano
Plants 2022, 11(24), 3514; https://doi.org/10.3390/plants11243514 - 14 Dec 2022
Cited by 12 | Viewed by 5435
Abstract
Leaves of guava (Psidium guajava L.) have been used in Thai folk medicine without any supporting evidence as a traditional herbal remedy for hair loss. Androgenetic alopecia (AGA) is chronic hair loss caused by effects of androgens in those with a genetic [...] Read more.
Leaves of guava (Psidium guajava L.) have been used in Thai folk medicine without any supporting evidence as a traditional herbal remedy for hair loss. Androgenetic alopecia (AGA) is chronic hair loss caused by effects of androgens in those with a genetic predisposition, resulting in hair follicle miniaturization. Our objectives were to provide the mechanistic assessment of guava leaf extract on gene expressions related to the androgen pathway in well-known in vitro models, hair follicle dermal papilla cells (HFDPC), and human prostate cancer cells (DU-145), and to determine its bioactive constituents and antioxidant activities. LC-MS analysis demonstrated that the main components of the ethanolic extract of guava leaves are phenolic substances, specifically catechin, gallic acid, and quercetin, which contribute to its scavenging and metal chelating abilities. The guava leaf extract substantially downregulated SRD5A1, SRD5A2, and SRD5A3 genes in the DU-145 model, suggesting that the extract could minimize hair loss by inhibiting the synthesis of a potent androgen (dihydrotestosterone). SRD5A suppression by gallic acid and quercetin was verified. Our study reveals new perspectives on guava leaf extract’s anti-androgen properties. This extract could be developed as alternative products or therapeutic adjuvants for the treatment of AGA and other androgen-related disorders. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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12 pages, 1972 KiB  
Article
HPLC-PDA/ESI-MS Analysis of Phenolic Compounds and Bioactivities of the Ethanolic Extract from Flowers of Moroccan Anacyclus clavatus
by Mounia Chroho, Mustapha Aazza, Aziz Bouymajane, Yassine Oulad El Majdoub, Francesco Cacciola, Luigi Mondello, Touriya Zair and Latifa Bouissane
Plants 2022, 11(24), 3423; https://doi.org/10.3390/plants11243423 - 8 Dec 2022
Cited by 5 | Viewed by 2422
Abstract
In this work, polyphenols were extracted from Anacylus clavatus flowers using a hydroethanolic solvent, and the obtained extract was studied for its total phenol and flavonoid contents and evaluated for its antioxidant and antibacterial capacities. The contents of total phenols and flavonoids were [...] Read more.
In this work, polyphenols were extracted from Anacylus clavatus flowers using a hydroethanolic solvent, and the obtained extract was studied for its total phenol and flavonoid contents and evaluated for its antioxidant and antibacterial capacities. The contents of total phenols and flavonoids were measured by employing gallic acid and quercetin as references, respectively, and the phenolic composition analysis was conducted using high-performance liquid chromatography combined with a photodiode array and electrospray ionization mass spectrometry (HPLC-PDA/ESI-MS). The antioxidant capacity of the extracts was tested using a potassium ferric reducing antioxidant power (PFRAP) assay, and the antibacterial activity assay was carried out against Gram-negative bacteria (Escherichia coli and Salmonella typhimirium) and Gram-positive bacteria (Staphyloccocus aureus and Listeria monocytogenes) using the broth microdilution assay. The phenolic and flavonoid contents of the extracts equaled 9.53 ± 0.48 mg GAE/g dm and 1.31 ± 0.06 mg QE/g dm, respectively. The chromatographic analysis of the phenolic profile detected 26 phenolic compounds belonging to phenolic acids, flavones and flavonols, and with the caffeoylquinic acid derivatives being the major phenolic compounds present in 12 isomers. Only one organic compound, viz. citric acid, was found. The extracts exhibited interesting antioxidant activity. Bacteriostatic activity towards Escherichia coli and bactericidal activity against Salmonella typhimirium, Staphyloccocus aureus and Listeria monocytogenes were determined. This study revealed that Anacyclus clavatus flower extracts contain phenolic compounds with interesting bioactivities. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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Review

Jump to: Research

30 pages, 3271 KiB  
Review
Saudi Arabian Plants: A Powerful Weapon against a Plethora of Diseases
by Hesham R. El-Seedi, Safaa M. Kotb, Syed G. Musharraf, Awad A. Shehata, Zhiming Guo, Sultan M. Alsharif, Aamer Saeed, Omer A. A. Hamdi, Haroon Elrasheid Tahir, Rasha Alnefaie, Rob Verpoorte and Shaden A. M. Khalifa
Plants 2022, 11(24), 3436; https://doi.org/10.3390/plants11243436 - 8 Dec 2022
Cited by 4 | Viewed by 6046
Abstract
The kingdom of Saudi Arabia (SA) ranks fifth in Asia in terms of area. It features broad biodiversity, including interesting flora, and was the historical origin of Islam. It is endowed with a large variety of plants, including many herbs, shrubs, and trees. [...] Read more.
The kingdom of Saudi Arabia (SA) ranks fifth in Asia in terms of area. It features broad biodiversity, including interesting flora, and was the historical origin of Islam. It is endowed with a large variety of plants, including many herbs, shrubs, and trees. Many of these plants have a long history of use in traditional medicine. The aim of this review is to evaluate the present knowledge on the plants growing in SA regarding their pharmacological and biological activities and the identification of their bioactive compounds to determine which plants could be of interest for further studies. A systematic summary of the plants’ history, distribution, various pharmacological activities, bioactive compounds, and clinical trials are presented in this paper to facilitate future exploration of their therapeutic potential. The literature was obtained from several scientific search engines, including Sci-Finder, PubMed, Web of Science, Google Scholar, Scopus, MDPI, Wiley publications, and Springer Link. Plant names and their synonyms were validated by ‘The Plant List’ on 1 October 2021. SA is home to approximately 2247 plant species, including native and introduced plants that belong to 142 families and 837 genera. It shares the flora of three continents, with many unique features due to its extreme climate and geographical and geological conditions. As plants remain the leading supplier of new therapeutic agents to treat various ailments, Saudi Arabian plants may play a significant role in the fight against cancer, inflammation, and antibiotic-resistant bacteria. To date, 102 active compounds have been identified in plants from different sites in SA. Plants from the western and southwestern regions have been evaluated for various biological activities, including antioxidant, anti-cancer, antimicrobial, antimalarial, anti-inflammatory, anti-glycation, and cytotoxic activities. The aerial parts of the plants, especially the leaves, have yielded most of the bioactive compounds. Most bioactivity tests involve in vitro assessments for the inhibition of the growth of tumour cell lines, and several compounds with in vitro antitumour activity have been reported. More in-depth studies to evaluate the mode of action of the compounds are necessary to pave the way for clinical trials. Ecological and taxonomical studies are needed to evaluate the flora of SA, and a plan for the conservation of wild plants should be implemented, including the management of the protection of endemic plants. Full article
(This article belongs to the Special Issue Research of Bioactive Substances in Plant Extracts II)
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