Evaluation of the antioxidant and cytotoxic potency of Euphorbia rigida and Arbutus andrachne methanol extracts in human hepatocellular carcinoma cell lines in vitro

Abstract Background Ethnobotanical studies on plants and their active compounds take a great interest in traditional medicine. After pharmacological and toxicological studies, there will be a possibility to be used in therapy. This study aimed to examine the in vitro antioxidant and cytotoxic activity of the methanol extracts of Arbutus andrachne L. and Euphorbia rigida M.Bieb. 10, 25, 50, 75, 100 and 150 µg mL−1 concentrations of A. andrachne and E. rigida were tested for antioxidant activity by using DPPH radical scavenging assays, total antioxidant capacity (phosphomolybdate assay) and and metal ion chelating activity. In addition, in vitro cytotoxic effects of this plants methanol extracts on Hep3B and HepG2 human hepatocellular carcinoma cell lines were evaluated at 24, 48 and 72 h. The cytotoxicity test was carried using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Results Methanol extract obtained from both plants showed increased antioxidant activity depending on the increase in concentration. When A. andrachne and E. rigida methanol extracts were compared in free DPPH scavenging activity, total antioxidant capacity and metal ion chelating activity, A. andrachne methanol extract was found more effective than E. rigida. Results from MTT assay revealed that except for 72 h treatment of HepG2 cells with 400 and 500 µgmL−1 extract concentrations, A. andrachne methanol extract did not show significant cytotoxic effects on either Hep3B or HepG2 cells at any concentration and treatment time. On the contrary, it significantly increased proliferation in Hep3B cells from 48 h and at a concentration of 100 µg mL−1. E. rigida methanol extract exhibited statistically significant cytotoxic activity on HepG2 cells after 48 and 72 h treatment. However, the treatment concentrations of E. rigida methanol extract were not as effective on Hep3B cells as on HepG2 cells. Conclusions According to our findings, it was determined that A. andrachne methanol extract did not have cytotoxic activity on neither Hep3B nor HepG2 cells, while E. rigida methanol extract had cytotoxic activity especially on HepG2 hepatocellular carcinoma cells. Further research is needed to identify and purify the active ingredients in E. rigida extracts