Antimicrobial, Antioxidant and Cytotoxic Activities of Cosmos Caudatus extracts

Abstract

This study aims to investigate the in-vitro antimicrobial potential of Cosmos caudatus against pathogenic bacteria, its antioxidant activity and cytotoxic effect on cancer cell lines. In vitro antimicrobial activities of ethanol and water extracts of Cosmos caudatus herb against pathogenic bacteria, Staphylococcus aureus, Salmonella sp., Pseudomonas aeruginosa and Escherichia coli were tested by agar well diffusion. Antioxidant properties of the extracts was evaluated by 2,2-diphenyl-1-picryl-hydrazyl radical scavenging activity method. Additionally, cytotoxic activity of the extracts on HCT 116 colorectal carcinoma cell line was determined by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Vero cells were used as a control. The quantification of these extracts showed that this plant is rich in secondary metabolites. Moreover, the conventional soxhlet extraction technique was more effective than maceration and ultrasonic assisted extraction technique. In antioxidants assay, both the ethanolic and water extracts through ultrasonic extraction method exhibited the highest DPPH free radical scavenging capacity compared to maceration and sohxlet extraction method. In antimicrobial assay, both the water and ethanol extracts showed no inhibitory action against the tested pathogenic bacteria. For anticancer activity, the F2, F7 and F8 fractions showed potent dose dependent cytotoxicity on Human Colorectal Carcinoma Cells with IC50 value of 15.53 ± 0.4, 32.72 ± 0.3 and 34.16 ± 1.4 μg/mL, respectively.