Conservation Strategies in the Genus Hypericum via Cryogenic Treatment
Hypericum polyanthemum Klotzsch ex Reichardt, an endemic species of Southern Brazil, was micropropagated on MS medium supplemented with 1.78 μM BAP. Shoot proliferation and rooting was achieved on hormone-free medium and plantlets survived acclimatization. The bioactive compounds: 6-isobutyryl-5,7-dimethoxy-2,2-dimethyl-benzopyran (HP1), 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran (HP2) and 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran (HP3) were quantified in the leaves, stems and roots of propagated and acclimatized plantlets and compared with the field-grown plants. The HPLC analysis revealed that the three benzopyrans are accumulated in the aerial parts and the concentration varied with the age of the plant whereas the roots were capable of accumulating only HP3. Greatest yield of HP1 (7.12 mg/g DW) was quantified in the leaves of the acclimatized plantlets, whereas the flowers of the plants from natural habitat displayed higher amounts of HP2 (11.04 mg/g DW) and HP3 (13.99 mg/g DW).