Isolation And Antimicrobial Activity Of Beta-Sitosterol-3-O-Glucoside From Lannea Kerstingii Engl. & K. Krause (Anacardiacea)

The emergence of more and more drug resistance bacteria has led to the study of the antimicrobial activity of the compound isolated from Lannea kerstingii Engl. & K. Krause (Anacardiacea) since the active principles of many drugs found in plants are secondary metabolites. A compound was isolated using dry vacuum liquid chromatography and eluting with CHCl3-EtOAc and monitored using TLC. The glycoside was characterized using H-1 NMR and C-13 NMR spectra recorded in DMSO-d6 at 400 MHz and 125 MHz, respectively. The antimicrobial activity of the compound was determined using agar diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal/minimum fungicidal concentration (MBC/MFC) was determined using broth dilution method. The compound isolated was found to be beta-sitosterol-3-O-glucoside. The beta-sitosterol-3-O-glucoside (200 mu g/ml) was active against S. aureus, Methicillin Resistant Staphylococcus aureus, P. mirabilis, S. typhi, K. pneumoniae, E. coli, B. subtilis with zone of inhibition ranging from 24mm to 34mm and inactive against P. aeroginosa and Proteus vulgaris. It was also active against the fungi C. albicans and C. tropicalis but inactive against C. krusei. The MIC ranged from 25 to 50 mu g/ml while the MBC/MFC ranged from 50 to 200 mu g/ml. These results show the wide spectrum antimicrobial activity of beta-sitosterol-3-O-glucoside.