Four new bibenzyl derivatives from Dendrobium candidum

Abstract

Four new bibenzyl derivatives, namely, dendrocandins F - I (1 - 4), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by the analysis of spectroscopic data. Dendrocandins F and G represent the fourth and fifth example of bisbibenzyl derivates with a dibenzopyran ring between two units, respectively. Dendrocandin H represents the first example of a bibenzyl derivative formed by a bibenzyl and a 1,4-phenanthraquinone unit via a dibenzopyran ring. Compounds 1 - 4 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. © 2009 Pharmaceutical Society of Japan.