Hyperdioxanes, dibenzo-1,4-dioxane derivatives from the roots of Hypericum ascyron

Six dibenzo-1,4-dioxane derivatives ( 1 – 6 ) were isolated from the roots of a Hypericaceous plant Hypericum ascyron . Spectroscopic analyses revealed 2 and 4 – 6 to be new compounds. The partial racemic natures of 1 – 3 were concluded by chiral HPLC analyses, while 5 was confirmed to be a racemate. The absolute configurations 1 – 4 were deduced on the basis of ECD calculations. Biological activity evaluation of the dibenzo-1,4-dioxane derivatives along with two related compounds: hyperdioxanes A ( 7 ) and B ( 8 ), previously isolated from the same plant material by our group demonstrated that 7 exhibit an anti-HIV activity (IC 50 5.3 μM, TI 7.2) while 8 showed an inhibitory effect on IL-1β production (inhibition rate: 72.3% at 6.3 μM) from LPS-stimulated microglial cells.