CYTOTOXICITY STUDY AND ISOLATION OF ANTICANCER COMPOUND FROM AQUEOUS AND ETHANOL EXTRACTS OF SOME MEDICINAL PLANTS

Abstract

The essence of the present study was to focus on the cytotoxicity of the aqueous and ethanol extracts of five medicinal plants viz. Margosa tree (Azadirachta indica), White Marudah (Terminalia arjuna), Ink nut (Terminalia bellerica), Myrobalan (Terminalia chebula) and Basil (Ocimum sanctum) and isolation of anticancer compound(s). The main objective of this study was to investigate the cytotoxic properties of selected medicinal plants with a view to discover potential candidates for the isolation of anticancer compounds and also for designing new anticancer herbal formulations. Brine shrimp lethality bioassay method was established for the present study and the cytotoxicity was reported in terms of lethality concentration (LD50). The shrimps were hatched and active shrimps were collected and used for the assay, suitable number of active shrimps were added to the diluted test solution and the surviving (larvae) shrimps were counted after 2, 4, 8 and 12 hours and lethality concentration LD50 was assessed. The ethanolic leaf extract of basil plant was super toxic with LD50 0.57 μg/ml, aqueous leaf extract of white marudah and margosa tree were highly toxic with LD50 1.07µg/ml and 1.11µg/ml respectively and aqueous leaf extract of myrobalan tree and ethanolic leaf extract of margosa tree were toxic with LD50 1.72 µg/ml and 1.71 µg/ml, respectively. The rest of the plant extracts were weakly toxic against brine shrimp nauplii. For isolation of anticancer compound, the ethanolic extract of basil leaves was detected to check whether it contains any compound that can inactivate the test animal. The thin layer chromatography (TLC) examination of ethanolic leaf extract of basil plant showed four distinct compounds at hexane: ethyl acetate (9:1, 15:1; V/V). The crude product of basil was purified by column chromatography. Four distinct compounds were isolated after column chromatography. Further, the cytotoxic effect of isolated compounds from ethanolic extract of basil leaves was studied. Among the four compounds isolated sample-1 was super toxic with LD50 0.80 μg/ml whereas, sample-2 was toxic with LD50 1.97 μg/ml and others two were weakly toxic against brine shrimp with LD50 2.26 μg/ml and 2.27 μg/ml, respectively. The findings of this study provide strong evidence that among the five medicinal plants examined the basil (Ocimum sanctum) is a potential candidate for the isolation of anticancer compounds and also for designing new anticancer herbal formulations.