The cytotoxic, antiproliferative and apoptotic effects of hypericum perforatum (St. John? s wort) on burkitt lymphoma cells (Namalwa and Daudi)

Hypericum perforatum L. (St. John?s wort) is widely used for treatment of pectic ulcers and skin wounds, infections, respiratory and inflammatory diseases in traditional medicine for centuries. Hypericum perforatum contains numerous compounds such as naphthodianthrones hypericin and pseudohypericin, flavonoids, and the phloroglucinols hyperforin and hyperforin with documented biological activity. In recent studies, H. perforatum has been proven to have antitumoral effects on several human cancer cell lines. In this study we aimed to investigate the antiproliferative, cytotoxic and apoptotic effects of H. perforatum extract on human Burkitt Lymphoma cells (Namalwa and Daudi).For this purpose, six different doses of H. perforatum extract (0,01-0,025-0,05-0,1-0,25-0,5 mg/ml) is experimented in cells for 24, 48 and 72 hours. Viability was measured by tripan blue dye exclusion method, metabolic activity was measured by WST-1 assay which analyze the number of viable cells by the cleavage of tetrazolim salts. Cytotoxicity was assessed by LDH (lactate dehydrogenase) release test and cell proliferation was assessed with BrdU test. Early apoptosis was assessed by Annexin V assay and late apoptosis was assessed by tunel (terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling) assay with fluorescent microscopy.Viability values which are gained according to tripan blue exclusion method, showed that after 72 hours incubation with 0,5 mg/ml concentration of H. perforatum extract was decreased the viability to % 32 in Namalwa cells and % 5 in Daudi cells which were found to be significantly different compared with control groups (p<0.05). Next, the effect of H. perforatum extract on the metabolic activity of cells were determined. According to the results metabolic activity was decreased to % 5 in Namalwa cells and % 1 in Daudi cells after 72 hours incubation with 0,5 mg/ml concentration of H. perforatum extract. In parallel LDH activity was also determined in both cells. The highest level of LDH activity was observed at 0,01 mg/ml concentration after 72 hours in Namalwa cells and 0,25 mg/ml concentration after 72 hours in Daudi cells. Similar to metabolic activity results, cell proliferation was decreased in a time and dose dependent manner. Early apoptotic cells were observed by Annexin V test after 24 hours and late apoptotic cells were observed by Tunel test after 48 hours treatment with 0,5 mg/ml concentration of H. perforatum extract by fluorescent microscopy.According to our results, we have shown that H. perforatum extract showed antiproliferative and cytotoxicity effects on both of Namalwa and Daudi cells in a time and dose dependent manner. H. perforatum extract inhibited the growth of Namalwa and Daudi cells with IC50 value of 0,028 mg/ml. It was found that the highest concentration of H. perforatum extract (0,5 mg/ml), induced early and late apoptosis on Burkitt Lymphoma cells within 24h and 48h, respectively.Key words: Hypericum perforatum, Burkitt Lymphoma, apoptosis