Effects of cytokinins and elicitors on the production of hypericins and hyperforin metabolites in Hypericum sampsonii and Hypericum perforatum

摘要

Hypericum perforatum L. (St. John's wort) and Hypericum sampsonii Hance are medicinal plants used in China in the treatment of viruses and other disorders. In the current study, we investigated the effects of cytokinins 6-benzylaminopurin (BA), zeatin (ZT) and thidiazuron (TDZ) on plant growth and production of hypericins (pseudohypericin and hypericin) and hyperforin. Our data suggested that culture of H. perforatum in modified MS (Murashige and Skoog) medium, with a 50% reduction in ammonium nitrate and potassium nitrate, and supplemented with BA (0.44 mu M) and indolebutyric acid (IBA, 0.049 mu M), resulted in increased production of hypericins. Similar results were noted with H. sampsonii with minor changes to the medium (0.46 mu M ZT and 0.049 mu M IBA). There were approximately 2.95-, 2.62-fold increases in H. perforatum pseudohypericin and hypericin production by TDZ (0.45 mu M) induction compared to the controls. No enhancement of hypericins and hyperforin production was elicited by TDZ in H. sampsonii. The elicitor methyl jasmonate (MJA, 50 mu M) and its analog, 2,3-dihydroxypropyl jasmonate (DHPJA, 50 mu M), were also used in H. perforatum and H. sampsonii shoot culture to increase secondary metabolite production, eliciting an increase in the production of hypericins and hyperforin. While leaf senescence and biomass inhibition were observed in cultures induced by MJA, no such effects were observed with DHPJA.