INVESTIGATION ON THE IN VITRO ANTIOXIDANT, ANTIMUTAGENIC AND CYTOTOXIC POTENTIAL OF THYMUS VULGARIS L. HYDRO-ALCOHOLIC EXTRACT

Aim: To evaluate the in vitro antioxidant, antimutagenic and cytotoxic property of hydro-alcoholic extract of Thymus vulgaris L. by subjecting it to free radical scavenging, Ames and MTT assay respectively.

Methods: Powdered Thyme leaves were extracted in a Soxhlet apparatus using 70% ethanol to obtain a dry extract. The extract was assessed for its total phenolic, tannin, flavonoid and flavonol content using quantitative assays. The antioxidant potential of Thyme was determined using DPPH^•, ABTS^•+, FTC and metal chelating assays. The in vitro inhibitory effects of Thyme on lipid peroxidation of liver and kidney along with erythrocyte hemolysis were performed following standard procedures. Further, the antimutagenic property of Thyme was investigated using Ames assay against TA 98 and TA 100 mutant strains of Salmonella typhimurium. The in vitro cytotoxicity assay of Thyme was examined following the MTT assay against Hep 2 and Hep G2 cell lines.

Results: The hydro-alcoholic extract of Thyme registered 91.42 ± 0.90, 63.23 ± 1.02, 55.01 ± 0.42 and 65.69 ± 0.43 mg/g extract of total phenolics, tannins, flavonoids and flavonols respectively. The Thyme extract effectively scavenged the DPPH^• (IC₅₀ 147.02 ± 1.84 µg/ml), ABTS^•+ (IC₅₀ 1.50 ± 0.39 µg/ml)and metal ions (IC₅₀ 878.38 ± 5.14 µg/ml) in a concentration dependent manner. It also significantly inhibited the in vitro lipid peroxidation in liver and kidney and also AAPH induced erythrocyte hemolysis. The percentage inhibitions on the last day of the FTC assay for the hydro-alcoholic Thyme extract and BHT were found to be 51.05% and 76.84% respectively. Depletion in the sodium azide induced His⁺ revertants was observed which justified the antimutagenic property of Thyme. A decrease in the viability of cancer cells were observed with increasing concentrations of Thyme extracts supporting its cytotoxic potential.

Conclusion: This study reveals that the common Thyme could serve as a potential antioxidant and chemotherapeutic culinary herb which may be justified by further in vivo studies.