Hypericum perforatum is a traditional medicinal plant with wound healing and antidepressant properties. Efficiency of micropropagation is often related to the long term maintenance of tissues in culture, which may alter the secondary metabolism of plants. The objective of this study was to evaluate growth and secondary metabolism of in vitro shoots of H. perforatum on short and long term maintenance of cultures (30 and 100 days). The effect of BA and NAA supplementation was evaluated during 30 days of culture. Adventitious shoots were cultivated on MS medium supplemented with 4.4mM BA alone or in combination with 0.05mM NAA for 30 days. A hormone-free medium was used as control. Shoots cultivated for 100 days were maintained in presence of 4.4mM BA. Biomass, multiplication of shoots, contents of phenolic compounds, flavonoids and hypericin were evaluated. No difference between BA and BA+NAA was observed on growth, multiplication of shoots and levels of flavonoids at the end of 30 days of culture. Production of phenolic compounds was promoted by addition of BA+NAA to the medium, whereas hypericin was increased by the presence of BA. The time of culture (30 and 100 days) affected all the parameters analyzed, except the levels of flavonoids in the short term experiment.
tissue culture; Hypericum perforatum; hypericin; phenolic compounds
