Quantification of reserpine content and antibacterial activity of Rauvolfia serpentina (L.) Benth. ex Kurz

Abstract

Reserpine is well known bioactive compound isolated from Rauvolfia serpentina. The aim of this study was to quantify reserpine content and evaluate the antibacterial activity of methanol extracts of R. serpentina against Salmonella typhimurium, Escherichia coli, Citrobacter freundii, Proteus vulgaris, Enterococcus faecalis and Staphylococcus aureus. Roots of R. serpentina were collected from Gadarpur and Uttarakhashi of Uttarakhand State, India. The antibacterial activity of the methanol extracts was evaluated by determination of minimum inhibitory concentration (MIC) and the diameter of zone of inhibition (ZOI) against both Gram positive and Gram negative bacteria using agar well diffusion method. The study reveals that reserpine content was higher (0.37%) in the sample collected from Gadarpur, whereas it was found to be 0.31% in sample collected from Uttarakashi. The highest zone of inhibition (13 mm) with lowest MIC (625 µg) was observed against Staphylococcus aureus and highest MIC (10 mg) was observed against Escherichia coli, whereas Proteus vulgaris was observed resistant to tested extracts upto 10 mg. R. serpentina contain good amount of reserpine and exhibited strong antibacterial activity against most of the tested human pathogenic bacteria. Therefore, the results of the study support the folklore claim of the plant species.     Key word: High performance thin layer chromatography (HPTLC), reserpine, ciprofloxacin, zone of inhibition, minimum inhibitory concentration.