Citrinal A, a novel tricyclic derivative of citrinin, from an algicolous fungus Penicillium sp. i-1-1

Citrinal A (1), a novel tricyclic compound with a rare tetrahydro-2H-benzofuro[7-b][1,4]dioxin-9(3H)-one skeleton, along with two known related compounds, citrinin (2) and 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (3) were isolated from an algicolous fungus Penicillium sp. i-1-1. The structure and stereochemistry of 1 were determined by comprehensive spectral and biogenic analysis. Its cytotoxic effects on the A-549 and HL-60 cell lines were evaluated.