Editorial: Molecular and Biotechnological Advancements in Hypericum Species

This special issue on the genus Hypericum (family Hypericaceae) consists of 12 articles focusing on recent advancements related to biosynthetic pathways, biotechnology, molecular biology, genomics, pharmacology, and related disciplines. Hypericum is well-known for its medicinal properties. There are about 487 Hypericum spp., which are distributed across every continent except Antarctica. Although the Mediterranean basin was recognized as a hot spot for Hypericum spp., Asian and American continents also account for significant biodiversity of Hypericum spp., out of which many are endemic. Due to anthropogenic exploitation and unsustainable collection practice, several Hypericum spp. have become critically rare/endangered and at least 17 species are included in the International Union for Conservation of Nature red list. The review by Bruňáková andČellárová deals with conservation strategies in the genus Hypericum via cryogenic treatment. The authors discuss the recent advances in the conventional two-step and vitrification-based cryopreservation techniques in relation to the recovery rate and biosynthetic capacity of Hypericum spp. Moreover, freezing tolerance as a necessary precondition for successful post-cryogenic recovery of Hypericum spp. is proposed. Within the genus, H. perforatum is the most important species, which is used in the treatment of mild to moderate depression since ancient times. Oliveira et al. comprehensively review the neuroprotective properties of H. perforatum in terms of its main biologically active compounds, their chemistry, pharmacological activities, drug interactions, and adverse reactions. They also discuss how H. perforatum extracts and its major components protect neurons from toxic insults either directly or indirectly as antioxidants. Hypericin is a characteristic constituent of the genus Hypericum, which can countervail complex diseases. Importantly, hypericin is a natural photosensitizing pigment and its photoexcitation properties are under intensive investigation with the aim of its utilization as a fluorescent diagnostic tool and anti-cancer agent for photodynamic therapy (PDT). Jendželovská et al. review the benefits of photoactivated and non-activated hypericin in preclinical and clinical applications focusing on multidrug resistance mechanisms. The demand of the pharmaceutical industry for new active compounds and drug leads is the driving force behind phytochemical analysis of medicinal plants. Although H. perforatum is phytochemically well-characterized, several other species still need to be elucidated for their chemical profiles. Crockett et al. report the isolation of a new phloroglucinol derivative,