PREDOMINATION OF DIMERS OVER NATURALLY-OCCURRING ANTHRAQUINONES IN SOIL

Four bianthraquinones and two monoanthraquinones were isolated as the major soil anthraquinones from a volcanic ash soil in Japan. They were identified as a new natural product 5,5'-biphyscion (named hinakurin) (3) and five known compounds, chrysotalunin (1), (-)-7,7'biphyscion ( 2), microcarpin (4), chrysophanol (5), and physcion (6) using MS, 1D N MR, and 2D NMR techniques. Although the dimers (1-4) are rarely found as natural products, they, along with 5 and 6, were ubiquitous and pre dominant over other anthraquinones in various soils from Japan and Nep al.