Extractives of Australian timbers. XVII. The isolation, structure and synthesis of koparin (7,2',3'-Trihydroxy-4'-methoxyisoflavone)

Abstract

The isolation of koparin, a minor constituent of the wood of Castanospermum australe, is described. By a combination of chemical and spectroscopic methods koparin was shown to be either 7,3?,4?-tri- hydroxy-2?-methoxyisoflavone (5) or 7,2?,3?-trihydroxy-4?- methoxyisoflavone (6). The latter compound has been synthesized by demethylenation of 7-hydroxy-4?-methoxy-2?,3?-methylenedioxyiso- flavone (9) and is identical with koparin.

Isolation and identification of berberine and berberrubine metabolites by berberine-utilizing bacterium Rhodococcus sp. strain BD7100

“…21) In other work, HDBA and DMBA, which are relatively expensive reagents, were used for the chemical synthesis of protoberberine and isoflavonoid derivatives for drug development. [22][23][24][25] In the present work, the isolation of HDBA and DMBA strongly suggests that the respective parent substrates are being degraded by cleavage of the protoberberine skeleton; the structures of these two benzeneacetic acid analogs are similar to the D-rings of BBR and BRU, respectively. Thus, this work represents the first example of microbial cleavage of the protoberberine skeleton.…”