Traditional uses, phytochemistry, and pharmacology of Elegia species : a review

In South Africa, plants belonging to the Restionaceae family possess an ecological dominance. As a result, they have been the subject of numerous morphological, anatomical, and evolutionary studies. However, few studies have focused on their phytochemical profile and their potential pharmacological activities. The genus Elegia L. is the second largest of this family comprising 52 species, which are mainly used as materials for thatching. Limited studies on the chemical constituents of Elegia species and their importance as medicinal plants have been undertaken. This review provides constructive and extensive information about the botanical characterization, distribution, traditional uses, phytochemistry and pharmacology of the genus Elegia. A comprehensive search of previously published literature was performed for studies on this genus, using databases with different key search words. This survey documented 52 Elegia species summarizing their previous taxonomic classification. In addition, 14 species were found to be studied for their phytochemical profile, revealing 14 chemical compounds. Concerning their biological activities, only one species (E. tectorum (L.f.) Moline and H.P.Linder) is reported for its anti-wrinkle activity. Moreover, two species are locally used for thatching and as materials for brooms. The present review highlights the Elegia genus as an important source of bioactive phytochemicals with flavonol glycosides being the main metabolites and reveals the uncharted territory of this genus for new research studies.http://www.mdpi.com/journal/scipharmdm2022Plant Production and Soil Scienc

The activity of Aloe arborescens Miller varieties on wound-associated pathogens, wound healing and growth factor production

Various Aloe L. species have been used worldwide to soothe and treat dermal wounds and burns. However, there is a lack of substantiative research on the efficacy of Aloe L. species for wound healing. The aim of this study was to investigate the differences in biological activities of the gel and ethanolic (EtOH) leaf extracts of seven Aloe arborescens Miller varieties. The extracts were investigated for their antibacterial activity against wound-associated bacteria, Staphylococcus aureus (ATCC 6538 and ATCC 25293) and Pseudomonas aeruginosa (ATCC 9027), as well as their nitric oxide (NO) scavenging potential. Varieties with antibacterial activity were further evaluated for wound closure and growth factor stimulation in human keratinocytes (HaCaT). The EtOH leaf extract of the ‘Eloff’ and ‘Jack Marais’ varieties displayed antibacterial activity against S. aureus ATCC 25293 (MIC of 500 and 250 μg/mL, respectively). The EtOH leaf extract of ‘Jack Marais’ displayed an MIC of 500 μg/mL against S. aureus ATCC 6538. The gel extract of ‘Le Roux’ exhibited antioxidant activity with a half maximal inhibitory concentration (IC50 of 2696 ± 582.66 μg/mL). The EtOH leaf extracts of ‘Eloff’ and ‘Jack Marais’ showed significant (p < 0.05) wound closure of 56.06 ± 1.47 and 73.72 ± 0.65%, respectively at 50 μg/mL and the ‘Jack Marais’ gel extract significantly stimulated wound closure (p < 0.05) by 77.02 ± 1.97 and 71.51 ± 1.11% at 50 and 100 μg/mL, respectively. Both the ‘Jack Marais’ gel extract (at 50 and 100 μg/mL) and the EtOH leaf extract (50 μg/mL), significantly (p < 0.05) increased platelet-derived growth factor (PDGF-AA) secretion to 601.09 ± 97.77, 1035.00 ± 913.98 and 559.43 ± 112.52 pg/mL, respectively. The ‘Jack Marais’ EtOH leaf extract exhibited the highest antibacterial activity, whereas the gel extract displayed the greatest potential to stimulate wound closure. This not only suggests a difference in biological activity among varieties but also between the type of extract (gel or leaf).The National Research Foundation of South Africa and by the Department of Science and Innovation (DSI), the Technology Innovation Agency (TIA) and South African Research Chairs Initiative (SARChI).http://www.elsevier.com/locate/sajb2023-06-16hj2023BiochemistryGeneticsMicrobiology and Plant PathologyPlant Production and Soil Scienc

THERAPEUTIC POTENTIAL OF GNIDIA CAPITATA L. F.: INVESTIGATIONS ON ITS ANTITYROSINASE, ANTIBACTERIAL, ANTIOXIDANT AND ANTICANCER ACTIVITIES

Background: Gnidia capitata L. F. belongs to the family Thymelaeaceae, and has been widely reported for its ethnobotanical uses, especially for the treatment of several human ailments which include skin conditions. However, there is limited information about the pharmacological properties of this plant as a potential cosmetic agent or pharmaceutical. The aim of this study was to evaluate the therapeutic potential of G. capitata for its anti-tyrosinase, antibacterial, antioxidant, anticancer and anti-mycobacterial properties. Materials and methods: G. capitata was extracted with methanol (MeOH), ethyl acetate (EtOAc), dichloromethane (DCM) and hexane (n-Hex). All extracts were tested in vitro for activities against Propionibacterium acnes (ATCC 11827) and Mycobacterium tuberculosis H37Rv (ATCC 27294). Tyrosinase inhibitory activity was screened using tyrosinase from Agaricus bispor. Antioxidant activity was investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Results: EtOAc, DCM and n-Hex extracts of the plant showed antibacterial activity against P. acnes with MICs of 125 μg/ml. The DCM and n-Hex extracts showed anti-mycobacterial activity with MICs of 500μg/ml. The methanolic extract showed the highest antioxidant activity with an IC50 of 41.83μg/ml. Conclusion: The findings presented in this study may explain the potential use of G. capitata for the treatment of certain skin conditions. The potent antioxidant activity could help control the negative effects associated with inflammatory mediators that are produced during the immune response in people that are affected by skin conditions

Potential medicinal plants for progressive macular hypomelanosis

Progressive macular hypomelanosis (PMH) is a hypopigmentation disorder caused by the bacterium identified as Propionibacterium acnes. The current treatments for PMH are antibiotics together with ultra violet radiation; however, UV radiation is not a recommended method to increase melanin production. Currently, there are no known plants used traditionally or medicinally for PMH. The objective of this study was to find plants that could stimulate tyrosinase activity induce melanin production and inhibit P. acnes' growth. Seventeen ethanol plant extracts, used traditionally in Africa for skin diseases, were screened for their antibacterial activity against P. acnes, their effect on monophenolase activity of tyrosinase and their cytotoxicity and stimulation of melanin production on mouse melanocytes (B16-F10). Hypericum revolutum Vahl subsp. revolutum (Hypericaceae) and Withania somnifera L. Dunal (Solanaceae) (twigs and leaves), combined with the known drug tetracycline, exhibited significant antibacterial activity against P. acnes, with the minimum inhibitory concentration ranging from 5.47 μg/ml to 14.06 μg/ml. The combination of a known drug with other antibacterial compounds not only decreases the concentration needed to inhibit bacterial growth, but also decreases the chances of bacterial resistance. W. somnifera was the only plant extracts that resulted in an increase in the monophenolase activity of tyrosinase. Four compounds typically present in plant extracts, namely coumarin, quercetin, withaferin and winthanone, were docked into the active site of tyrosinase enzyme to determine the interaction with active site residues. Mouse melanocytes (B16F10) treated with H. revolutum, W. somnifera (leaves) and Terminalia prunoides showed an increase in total melanin content as compared to untreated cells at 12 μg/ml, 12 μg/ml and 150 μg/ml respectively. Considering both the antibacterial activity and the stimulatory effect of the treatment on melanin production, H. revolutum and W. somnifera (leaves) could be considered as potential plants for further studies for PMH.National Research Foundationhttp://www.elsevier.com/l ocate/saj2018-07-30Plant Scienc

The anti-proliferative and anti-bacterial activity of argan oil and crude saponin extract from Argania spinosa (L.) skeels

INTRODUCTION: Argan oil is a well-known cosmeceutical that is commercially available. It is traditionally used for the treatment of acne and skin inflammation among others. The objective of this study was to assess the anti-proliferative and antibacterial activities of argan oil and a crude saponin extract from the argan tree (Argania spinosa (L.) Skeels) that is endemic to Morocco. MATERIALS AND METHODS: The anti-proliferative activity of argan oil and the crude saponin extract was assessed by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay on A431; HaCat; HeLa; MCF-7 and UCT-Mel 1 cells. The antibacterial activity was evaluated by the broth microdilution method against two species of bacteria: Cutibacterium acnes and Prevotella intermedia. RESULTS: The results of this study indicated that the argan oil sample did not inhibit the cell growth of the specified cell lines up to 1000µg/ml, while the crude saponin extract had low anti-proliferative activity. The minimal inhibitory concentration (MIC) values for both the argan oil and the crude saponin extract were found to be 500µg/ml against Cutibacterium acnes. No antibacterial activity from the argan oil or the crude saponin extract was evident against Prevotella intermedia up to a concentration of 12.5mg/ml. CONCLUSION: The results of this study indicated that argan oil and the crude saponin extract might have direct inhibitory effects on the growth and proliferation of Cutibacterium acnes. This finding supports the use argan oil as a treatment for acne vulgaris.National Research Foundationhttp://www.phcogfirst.com/content/pharmacognosy-journalpm2020Plant Production and Soil Scienc

Viability Reagent, PrestoBlue, in Comparison with Other Available Reagents, Utilized in Cytotoxicity and Antimicrobial Assays

This study compared different commercially available viability reagents. The growth indicator reagents include p-iodonitrotetrazolium violet (INT), PrestoBlue, and Alamar Blue which were used for antimicrobial analysis against Streptococcus mutans, Prevotella intermedia, Propionibacterium acnes, and Mycobacterium tuberculosis. PrestoBlue and Alamar Blue are resazurin based reagents that resulted in a quick and easily distinguishable colour change that allowed for visual readings. INT and Sodium 3′-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) are tetrazolium based reagents which are converted to a formazan dye in the presence of metabolically active mitochondria enzyme. For cell viability analysis, reagents XTT and PrestoBlue were compared. PrestoBlue was able to clearly indicate the minimum inhibitory concentration (MIC) of various positive drug controls on various microbial strains. PrestoBlue was also a good indicator of the 50% inhibitory concentration (IC50) of positive drug controls on various cell lines

Evaluation of wound healing and antibacterial potential of Greyia radlkoferi Szyszyl. Ethanolic leaf extract

Angiogenesis is an essential mechanism in both physiological and pathological functions, such as wound healing and cancer metastasis. Several growth factors mediate angiogenesis, including vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF). This study evaluated the potential wound healing activity of Greyia radlkoferi Szyszyl (GR) and its effect on growth factors regulating angiogenesis. The ethanolic leaf extract of GR was evaluated for antibacterial activity against wound associated bacteria; Staphylococcus aureus and Pseudomonas aeruginosa. It exhibited antibacterial activity against two strains of S. aureus (ATCC 25293 and ATCC 6538) displaying a minimum inhibitory concentration (MIC) at 250 and 500 μg/ ml, respectively. The antioxidant activity of the extract was investigated for nitric oxide (NO) scavenging activity and showed a fifty percent inhibitory concentration (IC50) of 1266.5 ± 243.95 μg/ml. The extract was further investigated to determine its effect on the proliferation and modulation of growth factors secreted by human keratinocytes (HaCaT). Its effect on wound closure was evaluated using the scratch assay, where non-toxic concentrations were tested, as determined by the antiproliferative assay against HaCat cells (IC50 > 400 μg/ml). Results showed that the extract significantly inhibited wound closure, with a percentage closure of 60.15 ± 1.41% (p < 0.05) and 49.52 ± 1.43% (p < 0.01) at a concentration of 50 and 100 μg/ml, respectively, when compared to the 0.25% Dimethyl sulfoxide vehicle control (65.86 ± 1.12%). Quantification of secreted growth factors from cell-free supernatant, collected from the scratch assay, revealed that the extract significantly decreased the concentration of platelet-derived growth factor (PDGF-AA) at both 50 (p < 0.05) and 100 μg/ml (p < 0.001) (443.08 ± 77.36 and 178.98 ± 36.60 pg/ml) when compared to the 0.25% DMSO vehicle control (538.33 ± 12.64 pg/ml). Therefore, whilst the extract showed antibacterial activity against wound associated bacteria, it did not induce wound healing but rather showed a significant inhibition of wound closure, which was confirmed by the inhibition of PDGF-AA, a major growth factor involved in angiogenesis. Therefore, the GR extract, should be considered for further investigation of anti-angiogenic and anti-metastatic properties against cancer cells.The Department of Science and Innovation (DSI), the Technology Innovation Agency (TIA) and South African Research Chairs Initiative (SARChI).https://www.frontiersin.org/journals/pharmacologydm2022Plant Production and Soil Scienc

Insights into tyrosinase inhibition by compounds isolated from Greyia radlkoferi Szyszyl using biological activity, molecular docing and gene expression analysis

Greyia radlkoferi ethanol extract and its five compounds were tested for their inhibitory activity against the mushroom tyrosinase enzyme and melanin production on melanocytes. The crude extract showed significant tyrosinase inhibition with IC50 of 17.96 μg/ml. This is the first report of the isolation of these 5 compounds from Greyia radlkoferi. 2',4',6'-Trihydroxydihydrochalcone showed the highest tyrosinase inhibition at 17.70 μg/ml (68.48 μM), with low toxicity when compared with crude extract. This compound is therefore, a key component in the crude extract, which is responsible for tyrosinase inhibitory activity. The RT-qPCR indicated that the mechanism of action is most likely post transcriptional. Further, the molecular docking study showed that tyrosinase inhibitory activity depends on interaction of the compound with Cu2+ ions at the active site. This is the first report of the tyrosinase inhibitory activity of the G. radlkoferi extract and molecular insights on interaction of its compounds with Cu2+ ions as the driving factor for tyrosinase inhibition. These results suggest that the extract of G. radlkoferi and the compound 2',4',6'-trihydroxydihydrochalcone have great potential to be further developed as pharmaceutical or cosmetic agents for use against dermatological disorders associated with melanin.The National Research Foundation [Grant 90355] and the Department of Science and Technology [Grant 0024/2015].http://www.elsevier.com/locate/bmc2017-11-30Plant ScienceChemistr

Assessing anti-inflammatory activities and compounds in switchgrass (Panicum virgatum)

SUPPLEMENTARY MATERIAL : TABLE S1: Putative identification of the secondary metabolites with known anti-inflammatory activities in switchgrass through untargeted metabolomics analyses.; TABLE S2: In vitro biological activities of the extracts derived from the four switchgrass cultivars. Antibacterial and antimycobacterial activities were evaluated against 2 bacterial strains Cutibacterium acnes and Mycobacterium smegmatis, respectively. Anticancer activity was investigated using human colorectal adenocarcinoma (HT-29) and human malignant melanoma (UCT-MEL-1) cell lines.Switchgrass is a bioenergy feedstock that potentially possesses multiple health benefits. However, the biological properties and associated bioactive compounds of switchgrass have not been adequately investigated. In the current study, we assessed the anti-inflammatory properties of switchgrass. Results from in vitro bioassays indicated that the methanolic extracts of switchgrass contained compounds exerting inhibitory effects on the expression of inflammatory mediators (TNF- , IL-6, IL-8, and IL-10) induced in the U-937 model system. The extracts derived from four switchgrass cultivars (Alamo, Kanlow, Liberty, and Show Me) inhibited the secretion of all inflammatory mediators examined, with the only exception of the Liberty extract, which showed no significant effect on IL-10 expression. The degree of cytokine inhibition was variable, depending on the particular cultivar, the concentrations tested, and the cytokines examined. A global metabolomics approach was utilized to putatively identify possible molecules with known anti-inflammatory capacities in different switchgrass cultivars using ultra-high performance liquid chromatography with high-resolution mass spectrometry (UHPLC-HRMS). The content of multiple bioactive antiinflammatory compounds in switchgrass was determined by liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analyses. Our results suggest that switchgrass, particularly the Alamo and Kanlow cultivars, may represent a promising natural anti-inflammatory source for the cosmetic, nutraceutical, and pharmaceutical industries.This work was supported by the USDA/ARS Dale Bumpers Small Farm Research Center, Agreement number 58-6020-6-001 from the USDA Agricultural Research Service, Center for Agroforestry at University of Missouri, University of Pretoria, and Missouri Department of Agriculture Specialty Crop Block Grant Program (SCBGP) #16SCBGPMO0003. The Sumner lab and the MU Metabolomics Center have been graciously supported by several entities over the years for the development of natural products profiling and plant metabolomics. These specifically include support from the University of Missouri, The Samuel Roberts Noble Foundation, Bruker Daltonics Gmbh, Agilent Technologies, US National Science Foundation (NSF)-JST Metabolomics for a Low Carbon Society #1139489, NSF MRI DBI #1126719, NSF RCN #1340058, and NSF MCB #1024976.https://www.mdpi.com/journal/agricultuream2023Plant Production and Soil Scienc