EVALUATION OF ANTIMICROBIAL, ANTIOXIDANT AND ANTICANCER ACTIVITIES OF<i> MENTHA</i><i> LONGIFOLIA</i> EXTRACT GROWN IN SOUTHERN SAUDI ARABIA

Mentha longifolia of the family Lamiaceae is used in traditional herbal medicines. In this study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method was used to evaluate cytotoxic activity of M. longifolia extract prepared using methanol, hexane and acetone solvents on human liver cancer (HepG2) and human breast cancer (MCF 7) cell lines. In addition, Hoechst 33342 and propidium iodide (PI) stains were used, which have the ability to stain nuclei of membranes of both dead and living cells. As a result, cells were stained with PI, suggesting that some of cells had undergone necrosis. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity technique was used to evaluate antioxidant properties ofM. longifolia extract and it was observed that antioxidant properties increased with concentration. Maximum antioxidant effect (33%) was observed at the highest concentration (800 mu g/ml). The antimicrobial properties of this plant were tested on 5 different microorganisms (Candida albicans, Klebsiella pneumoniae, Escherichia coli, Bacillus megaterium and Staphylococcus aureus) using well method. As a result of antimicrobial activity, it was found thatM. longifolia extract prepared with methanol at a concentration of 400 mg/ml exhibited the highest antibacterial activity against K. pneumoniae with a zone diameter of 17 +/- 1.25 mm, while methanol extract with a concentration of 50 mg/ml showed the lowest activity against B. megaterium with a zone diameter of 7 +/- 1 mm. In conclusion, it is suggested that M. longifolia extract has a strong potential in terms of cytotoxic, antioxidant and antibacterial activity and may be a precursor for In vivo and In vitro experiments.