Comparison of the growth-inhibitory effect of Hypericum perforatum L. extracts, differing in the concentration of phloroglucinols and flavonoids, on leukaemia cells

Abstract

In this study we compared, simultaneously, the growth-inhibitory effect of Hypericum perforatum L. extracts, containing various amounts of hyperforin (A 3.25%; B 2.21%; C 0.21% w/w) and flavonoids (A and B 5.3%; C 10% w/w), but closely same amounts of naphthodiantrones (0.3%) on two leukaemic cell lines K562 and U937 in the WST-1 assay. The GI50 (concentration of extracts which caused 50% of cell growth inhibition) for H. perforatum extracts analysed and characterized by HPLC for their biologically active constituents was 248.3-621.3 microg mL(-1) in K562 and 378.2-911.7 microg mL(-1) in U937 cells. The corresponding values of the three main groups were 1.6-3.9 microM naphthodianthrones, 1.0-40.7 microM phloroglucinols and 30.5-68.5 microM flavonoids. The results of this study supported the hypothesis that, apart from hyperforin and flavonoids, other components of the extract could be involved in its growth-inhibitory effect that it exerts without light activation.

Evaluation of the cytotoxicity, mutagenicity and antimutagenicity of a natural antidepressant, Hypericum perforatum L. (St. John’s wort), on vegetal and animal test systems

“…Other anti-proliferative activities of the methanol extract of H. perforatum have been observed in leukemic cells (K562 and U937), human colon carcinoma (HT-29) and cell lung carcinoma (H-460) [33,34]. Compounds isolated from H. chinense have demonstrated enhanced cytotoxicity against human cancer cell lines, including multidrug resistant cells [35,36].…”

Hypericum sp.: essential oil composition and biological activities

“…These extracts should be also evaluated for cancer chemopreventive potential. Different antiproliferative effects of Hypericum methanlic extracts on leukemia cell lines (K562 and U937), human colon carcinoma cells (HT-29) and non-small cell lung carcinoma (H-460) were also reported (Hostanska et al 2003;Ferraz et al 2005b). …”

Hyperforin, a new lead compound against the progression of cancer and leukemia?

“…The leukemia cell lines K562 and U937 were the more sensitive and HF was suggested to be, at least partly, responsible for these effects. 60 Indeed, purified HF inhibited the growth of these cells at GI (50) values about 12.5 mM. 61 Of note, these concentrations are rather high and may be cytotoxic in medium and long-term cultures.…”