Reduced perylenequinone derivatives from an endophytic Alternaria sp. isolated from Pinus ponderosa

Abstract

The consecutive solvent extraction of endophytic Alternaria sp. (DC401) isolated from Pinus ponderosa followed by chromatographic techniques led to the isolation of five perylenequinone compounds and one dihydronaphthaquinone derivative, which include three new perylenequinones (1–3). The compounds were identified as 6-methoxy-3,6a,7,10-tetrahydroxy-4,9-dioxo-4,5,6,6a,6b,7,8,9-octahydroperylene (1), 3,6a,9,10-tetrahydroxy-7,8-epoxy-4-oxo-4,5,6,6a,6b,7,8,9-octahydroperylene (2), 6-methoxy-3,6a,9,10-tetrahydroxy-7,8-epoxy-4-oxo-4,5,6,6a,6b,7,8,9-octahydroperylene (3), 3,6a,7,10-tetrahydroxy-4,9-dioxo-4,5,6,6a,6b,7,8,9-octahydroperylene (altertoxin I) (4), 3,6a,7,10-tetrahydroxy-4,9-dioxo-4,6a,6b,7,8,9-hexahydroperylene (dehydroaltertoxin I) (5), and 7-chloroscytalone (6). Structure of compounds 1–6 was determined on the basis of detailed spectroscopic analysis, as well as by comparison with literature reports. The antileismanial, antimicrobial, antimalarial and in vitro cytotoxic activities of compounds 1–6 were evaluated.