Phytochemical extraction and antimicrobial properties of different medicinal plants : Ocimum sanctum (Tulsi), Eugenia caryophyllata (Clove), Achyranthes bidentata (Datiwan) and Azadirachta indica (Neem)

Abstract

Aqueous ethanolic extract of four medicinal plants were subjected to in vitro antibacterial assay against human pathogenic Escherichia coli, Salmonella typhi, Salmonella paratyphi, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa employing cup diffusion method. Among four plants tested Eugenia caryophyllata (Clove) was found to be the most effective against S. typhi. All the plants were ineffective against E. coli and K. pneumonia. Achyranthes bidentata was found to be ineffective against all the tested organisms. The largest zone of inhibition (22 mm) was obtained with E. caryophyllata against S. typhi and Minimum Bactericidal Concentration (MBC) value of 5 mg/l was obtained with Azadirachta indica against S. typhi. K. pneumoniae and E. coli were found to be resistant with all the plant extracts. A qualitative phytochemical analysis was performed for the detection of alkaloids, glycosides, terpenoids, steroids, flavonoids, tannins and reducing sugars. Thin layer chromatography was also performed using solvent system chloroform, methanol and water (10:10:3) for the analysis of lipid present in plant extract. The present study will be successful in identifying candidate plant with different antimicrobial activity which could be further exploited for isolation and characterization of the novel phytochemicals in the treatment of infectious disease especially in light of the emergence of drug-resistant microorganisms and the need to produce more effective antimicrobial agents.   Key words: Antibacterial property, drug resistance, medicinal plant, zone of inhibition.