Phenolic compounds profiles during ex vitro acclimatization of micropropagated Hypericum polyanthemum

Accumulation of benzopyrans and total phenolic compounds were assessed in acclimatized field grown plants of Hypericum polyanthemum, an endemic species of southern Brazil, harvested at different developmental stages. The HPLC analysis of bioactive compounds 6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran (HP1), 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran (HP2) and 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran (HP3) revealed that the three benzopyrans are accumulated both in the vegetative and reproductive parts with maximum contents observed after 18 weeks (in the former) and 20 weeks (in the later) of plant growth (1.92+/-0.085 g % DW and 2.62+/-0.13 g % DW in the vegetative and reproductive parts, respectively). Highest contents of HP1 (1.56+/-0.12 g % DW) and HP2 (0.19+/-0.01 g % DW) were quantified in the green floral buds of the plants, whereas HP3 reached the highest level (1.02+/-0.08 g % DW) in the overblown flowers. The evaluation of total phenolic compounds showed that the vegetative parts accumulated the highest levels of the metabolites (51.93+/-0.67 mg QE (g DW)(-1)) after 16 weeks of plant growth. Considering the reproductive parts, the open flowers accumulated the greatest levels of the bioactive compounds (75.99+/-0.95 mg QE (g DW)(-1)). The results show that H. polyanthemum can be efficiently propagated and acclimatized to produce benzopyrans and other phenolic compounds.