Objectives:

The chemotherapeutic drug Doxorubicin affects not only cancer cells but also healthy cells in an undesirable manner. The purpose of this study was to investigate the protective role of Rosmarinic acid and Epigallocatechin gallate alone and in combination against Doxorubicin-induced oxidative stress, cytotoxicity and genotoxicity in healthy cells. In addition, this study evaluated the protein expression of the mammalian target of rapamycin (mTOR) protein in Chinese Hamster Ovary cell line (CHO-K1).

Materials and Methods:

The cell viability was analyzed by WST-1 cytotoxicity assay. mTOR in CHO-K1 cell line was determined by western blot analysis. DNA damage was analyzed using comet assay. Reactive oxygen species levels were determined microscopically, using dihydroethidium, staining method.

Results:

It was found that Rosmarinic acid showed more effective protection against Doxorubicin-induced cytotoxicity. Epigallocatechin gallate and Rosmarinic acid did not exert a genotoxic effect but Doxorubicin increased genotoxicity in CHO-K1. Rosmarinic acid and Epigallocatechin gallate significantly reduced the genotoxic effects of Doxorubicin in the comet assay. In the group treated with doxorubicin, the expression level of the mammalian target protein of rapamycin decreased from 250 nM to 2000 nM concentrations. Epigallocatechin gallate decreased mTOR protein levels when administered alone or in combination with Doxorubicin, but Rosmarinic acid did not show this effect. Rosmarinic acid decreased the intracellular reactive oxygen species generation in CHO-K1 cells. However, EGCG did not protect against oxidative stress and damaged cells due to its pro-oxidant properties at high concentrations.

Conclusion:

Epigallocatechin gallate and rosmarinic acid are promising plant-derived active components. Another important point is the evaluation of the safety of herbal products. It should be taken into account that herbal products may increase the toxicity of chemotherapeutic agents.

Keywords: DNA damage, Comet assay, Western blot, mTOR, WST-1 assay, oxidative stress