Pharmacological Activity of Phloroglucinols from Hypericum

The primary objective of our initial proposal was to test extracts and compounds purified from several species of the medicinally and economically important genus Hypericum (St. John`s Wort; Clusiaceae) against diseases affecting both humans and bees. A specific class of compounds, phloroglucinol derivatives, was selected due to their unique structures and known antibacterial, antifungal, antiviral, antimalarial, anti-inflammatory, anti-HIV, and antidepressant activities. Isolated compounds have the potential to serve as important lead structures in drug design. During the course of our first year of funding, isolation and structural elucidation of pure compounds was conducted using established chromatographic and spectroscopic methods. Extracts and compounds were tested in relevant bioassays through partnerships established with North American and European research institutions. Our initially stated primary objective - to search for new compounds that would help lead to the development of drugs with novel mechanisms of action for the treatment of physical and mental diseases in humans, as well as seek lead structures that could potentially be used to treat bacterial and fungal diseases in bees - has not changed. Our first year of research allowed us to enrich the scientific knowledge of the phytochemistry of Hypericum, investigate the role of the chemical constituents in pollinator interactions with the flowers, and facilitated the formation of collaborative links between Austrian and North American researchers. During the proposed 12-month extension of the project, however, we would like the opportunity to continue and complete fully the research proposed in the initial project, plus advance along new project directions that were identified as important during the first year of funding. In this time, we plan to continue our isolation and identification of phloroglucinol derivatives from selected North American species of Hypericum; finalize bioassay testing that had been initiated, but - due to time constraints - had not been completed; conduct chemical analyses of pollinators that had been observed to have significant interactions with Hypericum flowers, which were subsequently collected; and observe pollinator visitation patterns and behavior in regards to several species of Hypericum, which have been established in the Graz Botanical Garden. Final results will be presented at national conferences, and prepared for submission as papers to peer- reviewed journals.