Antigenotoxicity effects of Zataria multiflora Boiss on H2O2-induced DNA damage in human lymphocytes by comet assay

The present study aimed to explore the shielding effects of aqueous and ethanolic extracts of Zataria multiflora Boiss on human lymphocyte DNA damage using the comet assay.

This study was conducted as a laboratory experiment to investigate the protective effects of thyme in preventing DNA damage. Peripheral blood lymphocytes were isolated from 16 healthy volunteers. First, the cells were treated with 100 μM H2O2 and aqueous and alcoholic extracts of thyme leaves with a concentration of 2.5 mg/mL separately. Finally, the cells were incubated in a mixture of H2O2 to cause DNA damage with each of the two aqueous and alcoholic extracts at 4°C for 30 minutes. The amount of DNA migration in cells was measured using the Comet method, and DNA damage was expressed as three indicators: sequence length, percentage of DNA in the sequence, and the amount of sequence movement.

The results showed that the DNA damage of lymphocytes exposed to the ethanolic extract of Z. multiflora Boiss was significantly lesser than the H2O2-treated lymphocytes. In addition, tail length (µm) was 5.48±1.62 versus 22.82±6.90, tail DNA (%) was 4.56±1.55 in contrast to 16.00±4.55, and tail moment (µm) was 0.28±0.11 against 2.33±0.83 (p < 0.001).  The results showed that Z.multiflora Boiss aqueous and ethanolic extracts were significantly able to scavenge DPPH radicals through a possible radical scavenging activity mechanism.

As a result, the ethanolic extract had a better effect than the aqueous extract of Z. multiflora Boiss in preventing oxidative DNA damage to human lymphocytes.