Rapepol Bavovada

Hepatoprotective potential of extracts from seeds of Areca catechu and nutgalls of Quercus infectoria.

Aqueous extracts from seeds of Areca catechu L. (Arecaceae) (AC) and nutgalls of Quercus infectoria Oliv. (Fagaceae) (QI) were investigated for their hepatoprotective potential by studying their antioxidant capacity using four different methods, by determining their in vitro anti−inflammatory activity against 5-lipoxygenase, and by evaluating their hepatoprotective potential against liver injury induced by carbon tetrachloride (CCl4) in rats. AC and QI extracts exhibited potent antioxidant and anti-inflammatory activities. Treatment of rats with AC and QI extracts reversed oxidative damage in hepatic tissues induced by CCl4. It is suggested that extracts rich in either condensed or hydrolysable tannins and known for their potent antioxidant and anti-inflammatory activities, may potentially confer protection against oxidative stress−induced liver injury. These data should contribute to evidence-based traditional medicines for anti-inflammatory and hepatoprotective effects of both extracts.

Molecular Docking Studies and Anti-Tyrosinase Activity of Thai Mango Seed Kernel Extract

The alcoholic extract from seed kernels of Thai mango (Mangifera indica L. cv. ‘Fahlun’) (Anacardiaceae) and its major phenolic principle (pentagalloylglucopyranose) exhibited potent, dose-dependent inhibitory effects on tyrosinase with respect to L-DOPA. Molecular docking studies revealed that the binding orientations of the phenolic principles were in the tyrosinase binding pocket and their orientations were located in the hydrophobic binding pocket surrounding the binuclear copper active site. The results indicated a possible mechanism for their anti-tyrosinase activity which may involve an ability to chelate the copper atoms which are required for the catalytic activity of tyrosinase.

Inhibitory effect of tea polyphenols on local tissue damage induced by snake venoms

The methanolic extract of fresh tea leaves of Camellia sinensis L. (Theaceae) (CS) was assayed for its potential to inhibit enzymes with hydrolytic activity in Naja naja kaouthia Lesson (Elapidae) and Calloselasma rhodostoma Kuhl (Viperidae) venoms. These snake venom enzymes are responsible for the early effects of envenomation, such as local tissue damage and inflammation. The CS extract inhibited phospholipase A2, proteases, hyaluronidase and l‐amino acid oxidase in both venoms by in vitro neutralization and inhibited the hemorrhagic and the dermonecrotic activities of the venoms in vivo. It is suggested that the inhibitory potential of the CS extract against local tissue damage induced by snake venoms may be attributed to complexation and chelation between the venom proteins and the phenolic contents of the extract. Copyright

Molecular docking studies and anti-enzymatic activities of Thai mango seed kernel extract against snake venoms.

The ethanolic extract from seed kernels of Thai mango (MSKE) (Mangifera indica L. cv. ‘Fahlun’) (Anacardiaceae) and its major phenolic principle (pentagalloyl glucopyranose) exhibited dose-dependent inhibitory effects on enzymatic activities of phospholipase A2 (PLA2), hyaluronidase and L-amino acid oxidase (LAAO) of Calloselasma rhodostoma (CR) and Naja naja kaouthia (NK) venoms by in vitro tests. The anti-hemorrhagic and anti-dermonecrotic activities of MSKE against both venoms were clearly supported by in vivo tests. Molecular docking studies indicated that the phenolic molecules of the MSKE could selectively bind to the active sites or their proximity, or modify conserved residues that are critical for the catalysis of PLA2, and selectively bind to the LAAO binding pocket of both CR and NK venoms and thereby inhibit their enzymatic activities. The results imply a potential use of MSKE against snake venoms.

Alkaloids and a pimarane diterpenoid from Strychnos vanprukii

From the stem of Strychnos vanprukii, a gluco-indole alkaloid, 3,4-dehydropalicoside, and a pimarane diterpenoid, 7 beta-hydroxypimara-8,15-dien-14-one, were isolated together with four known alkaloids: palicoside, 3,4,5,6-tetradehydropalicoside, akagerine and 17-O-methylakagerine. The structures of these compounds were elucidated based on spectroscopic evidence.

Potentially cytotoxic triterpenoids from the root bark of Siphonodon celastrineus Griff.

A new oleanane-triterpene, 3β-acetoxy-11α-benzoyloxy-13β-hydroxyolean-12-one (1), was isolated along with a known quinone-methide triterpene, pristimerin (2), from the root bark of Siphonodon celastrineus Griff., a Thai medicinal plant of the family Celastraceae. Their structures were determined based on spectroscopic analysis.

Quinone-methide triterpenoids from Glyptopetalum sclerocarpum

Nine novel quinone-methide triterpenoids: 20-hydroxytingenone, 20,22beta-dihydroxytingenone, 20,22beta-dihydroxy-20-epi-tingenone, 20,21alpha-dihydroxy-22-oxo-21-desoxotingenone, 20-hydroxy-22-oxotingenone, 20-hydroxy-22-oxo-20-epi-tingenone, 21alpha-hydroxy-20,22-dioxo-30(20-->21)abeo-21-desoxotingenone, 20-oxo-20,21-seco-tingen-21-oic acid and 20-oxo-21-nor-20,21-seco-tingen-22-al, were isolated from the stem bark of Glyptopetalum sclerocarpum. Their structures were determined on the basis of spectroscopic evidence.

The inhibitory potential of Thai mango seed kernel extract against methicillin-resistant Staphylococcus aureus.

Plant extracts are a valuable source of novel antibacterial compounds to combat pathogenic isolates of methicillin−resistant Staphylococcus aureus (MRSA), a global nosocomial infection. In this study, the alcoholic extract from Thai mango (Mangifera indica L. cv. ‘Fahlun’) seed kernel extract (MSKE) and its phenolic principles (gallic acid, methyl gallate and pentagalloylglucopyranose) demonstrated potent in vitro antibacterial activity against Staphylococcus aureus and 19 clinical MRSA isolates in studies of disc diffusion, broth microdilution and time−kill assays. Electron microscopy studies using scanning electron microscopy and transmission electron microscopy revealed impaired cell division and ultra−structural changes in bacterial cell morphology, including the thickening of cell walls, of microorganisms treated with MSKE; these damaging effects were increased with increasing concentrations of MSKE. MSKE and its phenolic principles enhanced and intensified the antibacterial activity of penicillin G against 19 clinical MRSA isolates by lowering the minimum inhibitory concentration by at least 5−fold. The major phenolic principle, pentagalloylglucopyranose, was demonstrated to be the major contributor to the antibacterial activity of MSKE. These results suggest that MSKE may potentially be useful as an alternative therapeutic agent or an adjunctive therapy along with penicillin G in the treatment of MRSA infections.

Factors Influencing Oral Bioavailability of Thai Mango Seed Kernel Extract and Its Key Phenolic Principles.

Mango seed kernel extract (MSKE) and its key components (gallic acid, GA; methyl gallate, MG; and pentagalloyl glucopyranose, PGG) have generated interest because of their pharmacological activities. To develop the potential use of the key components in MSKE as natural therapeutic agents, their pharmacokinetic data are necessary. Therefore, this study was performed to evaluate the factors affecting their oral bioavailability as pure compounds and as components in MSKE. The in vitro chemical stability, biological stability, and absorption were evaluated in Hanks’ Balanced Salt Solution, Caco-2 cell and rat fecal lysates, and the Caco-2 cell model, respectively. The in vivo oral pharmacokinetic behavior was elucidated in Sprague-Dawley rats. The key components were unstable under alkaline conditions and in Caco-2 cell lysates or rat fecal lysates. The absorptive permeability coefficient followed the order MG > GA > PGG. The in vivo results exhibited similar pharmacokinetic trends to the in vitro studies. Additionally, the co-components in MSKE may affect the pharmacokinetic behaviors of the key components in MSKE. In conclusion, chemical degradation under alkaline conditions, biological degradation by intestinal cell and colonic microflora enzymes, and low absorptive permeability could be important factors underlying the oral bioavailability of these polyphenols.

Anti-necrosis potential of polyphenols against snake venoms.

Polyphenols from the extracts of Areca catechu L. and Quercus infectoria Oliv. inhibited phospholipase A2, proteases, hyaluronidase and L-amino acid oxidase of Naja naja kaouthia Lesson (NK) and Calloselasma rhodostoma Kuhl (CR) venoms by in vitro tests. Both extracts inhibited the hemorrhagic activity of CR venom and the dermonecrotic activity of NK venom by in vivo tests. The inhibitory activity of plant polyphenols against local tissue necrosis induced by snake venoms may be caused by inhibition of inflammatory reactions, hemorrhage, and necrosis. The result implies the therapeutic potential of plant polyphenols against necrosis in snakebite victims.