Production of polyphenolic compounds in shoot cultures of Hypericum species characteristic for the Balkan fl ora

Th is work compares the polyphenolic compounds content in the in vitro shoot cultures of Hypericum rumeliacum, H. tetrapterum and in the hypericin non-producing H. calycinum, which are characteristic for the Balkan fl ora. In addition, the impact of diff erent vitamin supplementation to culture medium on secondary metabolites is discussed. Th ough Gamborg’s vitamins supplementation improved growth parameters in vitro, it resulted in reduced polyphenolics levels in comparison with Murashige and Skoog’s vitamins. Preliminary experiments on cryopreservation of H. rumeliacum which were previously performed, gave low rates of plant survival. Th erefore, as a part of a broader study for improving the approach for cryopreservation of H. rumeliacum, phenolics accumulation, total soluble sugars content as well as malondialdehyde and hydrogen peroxide content were studied during preculture treatment prior to dehydratation and liquid nitrogen immersion and results are discussed in this work.