No abstract

The triterpenoid, bauerenol, from Suregada angustifolia (Baill. ex Muell.-Arg.) Airy Shaw (Euphorbiaceae) was screened for anti-cancer property using hepatocellular carcinoma cell line, HepG2. Bauerenol exhibited growth inhibitory and apoptosis inducing potential against HepG2 cancer cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxic assay revealed that bauerenol treatment significantly reduced the growth of HepG2 cells in a time- and dose-dependent manner with 50% growth inhibitory concentration doses of 45 and 25 µg/mL at 24 and 48 h treatments, respectively. Bauerenol-induced cell death reflected apoptotic morphological features, that is, cell membrane blebbing, vacuolization, chromatin condensation, and nuclear fragmentation. In addition, bauerenol treatment diminished the mitochondrial membrane potential, by inducing the efflux of cytochrome c, downregulating the levels of anti-apoptotic Bcl-2 as well as upregulating the levels of pro-apoptotic Bax, and inducing caspase activation and poly (ADP-ribose) polymerase cleavage. Moreover, bauerenol treatment activates p38MAPK and inactivates the anti-apoptotic kinases Akt and ERK1/2 through the induction of reactive oxygen species. Furthermore, bauerenol-mediated S-phase arrest was associated with downregulation of cell cycle-rate-limiting factor (cyclin D1) and upregulation of cyclin-dependent kinase inhibitor p21 and tumor suppressor p53. Interestingly, pre-treatment of cells with reactive oxygen species inhibitor and p38 inhibitor significantly decreases bauerenol-induced cytotoxicity, Bax upregulation, and p38 activation. This study clearly states that bauerenol induces cell cycle arrest and apoptosis through the reactive oxygen species-dependent p38MAPK activation in HepG2 cancer cells.

The whole plant of Phyllanthus wightianus (PW) was investigated for the antioxidant effects of three successive extracts: hexane (PWHE), chloroform (PWCE) and methanol (PWME), using standard in vitro models. The PWME exhibited a strong scavenging effect on 2,2-diphenyl-2-picryl hydrazyl (DPPH) free radicals and nitric oxide radical inhibition activity, due to possessing the highest content of tannins. The free radical scavenging effect of PWME was comparable with that of reference antioxidants. The extracts were subjected to isolation of their compounds: isomeric sterol mixture (1) [stigmasterol (1a), compesterol (1b) and β-sitosterol (1c)], fredilin (2), lupeol (3), gallic acid (4), bergenin (5), geraniin (6), corilagin (7) and ellagic acid (8) were established through the use of column chromatographic methods and spectral data. The percentage of tannins was also determined and estimated using the HPLC method. The data suggest that tannins are the active antioxidant compounds of P. wightianus. This study provides proof for the ethnomedical claims and reported biological activities of this plant. The plant therefore has very good therapeutic potential.

Phytochemical analysis of the stem bark of Suregada angustifolia (Baill. ex Muell. Arg.) Airy Shaw resulted in the isolation of six known compounds: friedelin, epifriedelinol, n-octacosanol, a-amyrin, b-sitosterol, and b-sitosterol-3 b-D-glucopyranoside. The aqueous and various solvent (methanol, chloroform, and hexane) extracts of stem bark were tested by the agar welldiffusion method against 12 human pathogenic bacteria. Maximum antibacterial activity was observed in the order of chloroform, hexane, and methanol extracts. Aqueous (room temperature, boiled, and autoclaved) extracts did not demonstrate any activity. The results of the current investigation correspond positively with the claims of the ethnomedicinal uses.

The antibacterial activity and phytochemicals of the leaves of Stylosanthes fruticosa were evaluatedagainst three Gram-positive bacteria viz. Bacillus cereus, Staphylococcus faecalis ,Staphylococcus aureusand five Gram-negative bacteria viz. Klebsiella pneumonia Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium ,and Proteus vulgaris. Both polar and nonpolar extracts viz. acetone, chloroform, ethanol,  and aqueous extracts were prepared and studied for antibacterialactivity using disc diffusion method. The majority of the significant antibacterial activity was observed in the ethanol extracts. The other solvent extracts showed satisfactory results. In general, gram-negative bacteria are more resistant to antibiotics than gram-positive bacteria . The resistance is due to the differences in their cell wall composition. In gram-negative bacteria the outer membrane acts as a great barrier to many environmental substances including antibiotics. Presence of thick murine layer in the cell wall prevents the entry of the inhibitors . But our results revealed a controversy report that gram-positive bacteria are more susceptible to the crude extracts than gram-negative bacteria.. Theresults which are obtained with acetone, ethanol  and chloroform extract ofleaf exhibited significant antibacterial activity, a property that supports traditional use of the plant inthe treatment of some diseases as broad spectrum antibacterial agents.