Tricycloalternarene derivatives produced by an endophyte alternaria alternata isolated from Maytenus hookeri.

A new tricycloalternarene derivative, named tricycloalternarenal (1), together with three known compounds was isolated from the cultures of Alternaria alternata, an endophytic fungus in the leaves of the plant Maytenus hooker! (Celastraceae). Structure of 1 was established as (2E)-6-(3, 3a, 5, 6, 7, 8, 9, 9a-octahydro-5-hydroxy-3a-methyl-8-oxo-cyclo-penta[b]chromen-1-yl)-2-methylhept-2-enal by spectroscopic methods, including 2D-NMR experiments. The remaining compounds were determined as tricycloalternarene-3b (2), alterperylenol (3), and dihydroalterperylenol (4).