Hypericum Species as Sources of Valuable Essential Oils

Since ancient times, the essential oils (EOs) of many aromatic plants have been used as bioactive ingredients in drug, food and cosmetic formulations all over the world. Significant biological properties have also been attributed to Hypericum EOs. Hypericum is a genus of about 450 species in the Guttiferae family, formerly often treated separately in their own Hypericaceae family. Despite the large number of species, only Hypericum perforatum has been studied in depth by the pharmaceutical industry to control the content of its well known bioactive constituents hypericins, hyperforins and flavonoids in the flowering aerial parts. As a consequence, efficient commercial products based on the hydroalcoholic extracts or oil of H. perforatum are already commercially available as antidepressive agents or to treat skin burns. However, only a few studies have been performed on the EO constituents of H. perforatum and other members of this species. In the last few years some papers have been published on Hypericum EOs, but the number of these studies is still limited and the results are not homogenous enough to justify the use of Hypericum EOs as phytomedicines or dietary supplements. The present study is an overview of the production of EOs from Hypericum species. A summary of the typical EO constituents found in wild or cultivated plants, as well as their biological activities, is provided to point out the most significant Hypericum species, valuable as potential sources of EOs and bioactive ingredients. _____________________________________________________________________________________________________________