ANTIMICROBIAL AND LARVICIDAL POTENTIAL OF SWEET BASIL (OCIMUM BASILICUM L.) EXTRACTS AGAINST LYMPHATIC FILARIASIS VECTOR CULEX QUINQUEFASCIATUS

Abstract

This study was designed to evaluate the antimicrobial and insecticidal potential of the extracts of medicinal plant Ocimum basilicum (basil). The plant parts including roots, leaves and shoots were dried and grinded into fine powder. Ethanol and acetone were used for crude extraction and later on extracts were dissolved in methanol. The antimicrobial activity of the extracts was determined by disc diffusion and agar well diffusion assays. The toxicity of the extracts was determined through microwell cytotoxicity assay against Artimia salina. Finally, insecticidal potential of the extracts was determined by larvicidal assay against Culex quinquefaciatus mosquito. The methanolic extracts exhibited an impressive antimicrobial activity against various Gram-positive and Gram-negative bacterial test strains. A promising larvicidal activity against Culex quinquefaciatus larvae was observed with larval mortality up to 80-90% in 48 hours. LC50 value for leaf extracts after 24 hours of exposure was 0.4 ppm and LC90 of 6.3 ppm. In contrast, lower cytotoxicity (35%) was observed against brine shrimp (Artemia salina) larvae after 24 hours of exposure. The chemical screening by TLC and HPLC/UV showed that the methanolic extracts contain active molecules belonging to various plants metabolites including indols, alkaloids and flavonoids. The study revealed that the extracts of Oscimum bacillicum could be exploited commercially as antimicrobials and as insecticides.