Chemical Constituents of Dissotis perkinsiae (Melastomaceae) and Their Antimicrobial Activity.

The phytochemical study of the Methanol/dichloromethane extract of the leaves of Dissotis perkinsiae led to the isolation and identification seven compounds: Ursolic acid (1); Sitosterol-β-D-glucoside (2); Isoquercitrin (3); Quercetin-3-O-β-galactoside (4);Kaempferol-3-O-β-D-glucoside (5); Kaempferol-7-O-β-D-glucoside (6); Trans-Tiliroside (7). Their structures were elucidated on the basis of spectroscopic analysis and by comparison of their spectral data with those reported in the literature. The results of antimicrobial activity indicated that the MIC vary from >0.5 to 0.00078 mg/mL on yeasts and from >0.5 to 0.25 mg/mL on bacteria. Sitosterol-β-D-glucoside was the most active with the broad spectrum (MIC=0.125mg/mL on C. albicans, MIC=0.0625 mg/mL on C. kruseiand MIC=0.0078 mg/mL on C. parapsilosis). Kaempferol-7-O-β-D-glucoside was the most active on C. krusei (MIC=0.0039 mg/mL). The anti yeat activity of Sitosterol-β-D-glucoside and Kaempferol-7-O-β-D-glucoside were better thanfluconazole (0.032mg/mL) on C. parapsilosis (MIC 0.0078 mg/mL) and C. krusei (0.0039 mg/mL) respectively. Sitosterol-β-D-glucoside and Trans-Tiliroside showed weak inhibitotry activity against S. enteric and S. aureus with MIC value of 0.5mg/mL. Respectively this inhibitory effect was lower activities observed with Chloremphenicol and Ampicillin (0.000488 mg/mL). The results of this study suggest that Dissotis perkinsiae represent an untapped source of compounds with potential antimicrobial activity that could be explored in the development of new therapeutic natural products.

Phytochemistry and in vitro Antimicrobial, Antioxydant Activities of Entandrophragma candollei H.

The research work was conducted to investigate the in vitro antimicrobial and antioxidant activity of extract of E. candollei (Family-Meliaceae). Phytochemical screening was done. Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Minimal inhibitory concentration of promising extracts was determined by broth microdilution method. The phytochemical screening showed the presence of flavonoids compounds, tannins and saponins. The inhibition diameters were ranging from 7 to 17 mm and Minimum Inhibitory Concentrations (MIC) from 156.25 to 2500 μg/mL. The ethyl acetate and ethanolic extract revealed a high radical scavenging activity with IC50 ranging from 9.1026 to 11.8298 μg/mL. The Ferric reducing power activity was obtained with active concentration ranging from 12.5 to 200 μg/mL. These results suggest that extracts from E. candollei possess antibacterial and antioxidant activities and therefore justifies their usage in traditional medicine for the treatment of various diseases.