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.