Phytochemical Investigation of Lepionurus sylvestris Blume and Their Anti-Diabetes Effects via Anti-Alpha Glucosidase and Insulin Secretagogue Activities Plus Molecular Docking.

This study presents a phytochemical investigation of Lepionurus sylvestris leaf extracts and their anti-diabetic activities. Traditionally, L. sylvestris leaves were used as vegetables and food in local recipes, but the root extracts of the plant can also be used in body tonic and erectile dysfunction treatments. Following a preliminary anti-diabetic activity screening test, the 80% ethanolic leaf extract exhibited potent anti-alpha glucosidase activity. So, the leaves' active components were selected for further investigation. Firstly, the plant was extracted via maceration using lower to higher polarity solvents such as hexane, ethyl acetate, ethanol, and water, respectively, to obtain the four crude extracts. Then, the phytochemicals contained in this plant were investigated via classical column chromatography and spectroscopy techniques. Anti-diabetic activity was evaluated via anti-alpha glucosidase and insulin secretagogue assays. The results showed that five compounds were isolated from the fractionated ethanolic leaf extract: interruptin A; interruptin C; ergosterol; diglycerol; and 15-16-epoxy-neo-cleoda-3,7(20),13(16),14-tetraene-12,17:18,19-diolide, a new diterpene derivative which is herein referred to as lepionurodiolide. Interruptin A and the new diterpene derivative exhibited the greatest effect on anti-alpha glucosidase activity, showing IC50 values of 293.05 and 203.71 µg/mL, respectively. Then, molecular docking was used to study the sites of action of these compounds. The results showed that interruptin A and the new compound interacted through H-bonds with the GLN279 residue, with a binding energy of -9.8 kcal/mol, whereas interruptin A and C interacted with HIS280 and ARG315 a with binding energy of -10.2 kcal/mol. Moreover, the extracts were investigated for their toxicity toward human cancer cells, and a zebrafish embryonic toxicity model was used to determine herbal drug safety. The results indicated that ethyl acetate and hexane extracts showed cytotoxicity to both Hela cells and human breast adenocarcinomas (MCF-7), which was related to the results derived from using the zebrafish embryonic toxicity model. The hexane and ethyl acetate presented LC50 values of 33.25 and 36.55 µg/mL, respectively, whereas the ethanol and water extracts did not show embryonic toxicity. This study is the first of its kind to report on the chemical constituents and anti-diabetic activity of L. sylvestris, the leaf extract of which has been traditionally used in southern Thailand as a herbal medicine and food ingredient.

Potential applications of Rhodomyrtus tomentosa leaf extract as natural anti-staphylococcal additive in food systems: Efficacy and in vivo safety evaluation.

This work aimed to explore the potential use of Rhodomyrtus tomentosa ethanol leaf extract (RTEL) as an alternative food preservative agent for controlling the growth of Staphylococcus aureus. Antibacterial activities against food-isolated S. aureus were performed using disc diffusion and broth microdilution assays, followed by evaluating in vivo subacute oral toxicity of the extract. Salad dressing was used as a food model to study bactericidal properties and consumer acceptability. RTEL remarkably inhibited S. aureus with minimum inhibitory concentrations (MICs) ranging from 7.81-62.5 µg/mL. Repeated oral doses (5, 50, and 300 mg/kg RTEL) for 28 days did not affect any of the measured toxicity parameters. The no-observed-adverse-effect-level (NOAEL) of RTEL was noted as more than 300 mg/kg body weight/day. The utilization of RTEL (12.5 mg/mL) in the vinaigrette salad dressing did not affect the consumer acceptability of the product, remarkably killed the pathogen within 3-9 h of exposure. The results indicated that RTEL is safe and effective as a natural anti-staphylococcal controlling agent that could be utilized in food systems. Further work is required on the effects of enterotoxin production, an important virulence factor of S. aureus responsible for food-borne disease.

A Comparative Study of Chemical Profiling and Bioactivities between Thai and Foreign Hemp Seed Species (Cannabis sativa L.) Plus an In-Silico Investigation.

Hemp (Cannabis sativa L.) is a plant widely used by humans for textiles, food, and medicine. Thus, this study aimed to characterize the chemical profiling of 12 hemp seed extracts from Thai (HS-TH) and foreign (HS-FS) samples using gas chromatography-mass spectrometry (GC-MS). Their antibacterial activity and α-glucosidase inhibitory activity were assayed. Linoleic acid (17.63-86.53%) was a major component presented in Thai hemp seed extracts, while α,ß-gluco-octonic acid lactone (30.39%), clionasterol (13.42-29.07%), and glyceryl-linoleate (15.12%) were detected as the main metabolites found in foreign hemp seed extracts. Furthermore, eight extracts from both Thai and foreign hemp seed exhibited antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus aureus, and Cutibacterium acnes, with MIC values ranging from 128 to 2048 µg/mL. Interestingly, the ethanol extract of Thai hemp seed (HS-TH-2-M-E) showed superior α-glucosidase inhibition (IC50 value of 33.27 ug/mL) over foreign species. The combination between Thai hemp species (HS-TH-2-M-E) and acarbose showed a synergistic effect against α-glucosidase. Furthermore, the docking investigation revealed that fatty acids had a greater impact on α-glucosidase than fatty acid esters and cannabinoids. The computational simulation predicts a potential allosteric binding pocket of guanosine on glucosidase and is the first description of gluco-octonic acid's anti-glucosidase activity in silico. The findings concluded that Thai hemp seed could be used as a resource for supplemental drugs or dietary therapy for diabetes mellitus.

Antiplasmodial Properties of Aqueous and Ethanolic Extracts of Ten Herbal Traditional Recipes Used in Thailand against Plasmodium falciparum.

This study evaluated the in vitro and in vivo antiplasmodial efficacy and toxicity of aqueous and ethanolic extracts from traditional recipes used in Thailand. The aqueous and ethanolic extracts of ten traditional recipes were tested for in vitro antiplasmodial activity (parasite lactate dehydrogenase assay), cytotoxicity (MTT assay), and hemolysis). Oxidant levels were measured using cell-permeable probe 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate fluorescent dye-based assays. The best candidate was chosen for testing in mouse models using 4-day suppressive and acute toxicity assays. An in vitro study showed that ethanolic extracts and three aqueous extracts exhibited antiplasmodial activity, with an IC50 in the range of 2.8-15.5 µg/mL. All extracts showed high CC50 values, except for ethanolic extracts from Benjakul, Benjalotiga, and Trikatuk in HepG2 and Benjalotiga and aqueous extract from Chan-tang-ha in a Vero cell. Based on the results of the in vitro antiplasmodial activity, an aqueous extract of Triphala was chosen for testing in mouse models. The aqueous extract of Triphala exhibited good antiplasmodial activity, was safe at an oral dose of 2 g/kg, and is a potential candidate as a new source for the development of antimalarial drugs.

The Standardized Wood Extract of Albizia myriophylla: Its Potential as an Active Ingredient in an Anti-inflammatory Herbal Gel Formulation.

Albizia myriophylla has been used in Thai folk medicine for treating inflammation-related diseases. The wood of this medicinal plant is traditionally used as a single herbal drug in the form of an aqueous decoction and as a component in several Thai herbal formulations for the remedy of fever, sore throat, and aphthous ulcers. This study aimed to evaluate in vivo the anti-inflammatory potential and possible mechanism of action of the standardized wood extract of A. myriophylla as well as to investigate the anti-inflammatory activity and physicochemical properties of the developed herbal gel formulation containing standardized wood extract of A. myriophylla. Results of quantitative HPLC analysis demonstrated that the standardized wood extract of A. myriophylla contained 22.95 mg/g of 8-methoxy-7,3',4'-trihydroxyflavone, a bioactive marker compound of A. myriophylla. The standardized wood extract of A. myriophylla (1% w/v) exhibited remarkable inhibition (54.4 - 80.3%) in the croton oil model of topical inflammation at all assessment times, comparable to standard indomethacin (55.3 - 63.6%). Real-time quantitative reverse transcription-polymerase chain reaction was performed to clarify the anti-inflammatory mechanism of standardized wood extract of A. myriophylla, and the result showed that this standardized extract decreased lipopolysaccharide-induced nitric oxide synthase mRNA levels in a dose-dependent manner. The developed herbal gel containing standardized wood extract of A. myriophylla (1% w/w) had good physicochemical characteristics and exhibited potent inhibition (51.4 - 77.8%) of inflammation in a rat ear edema model at all assessment times, comparable to indomethacin gel (33.3 - 40.5%). The notable anti-inflammatory activity of standardized wood extract of A. myriophylla and its developed herbal gel formulation indicates their potential application as natural anti-inflammatory agents.