BIOTRANSFORMATION OF AN ACYCLIC NEOLIGNAN IN RATS

The biotransformation of an acyclic neolignan, (+)-erythro-(4,7-dihydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4' neolignan, in rats has been investigated. After administration of (+)-erythro-(4,7-dihydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan to rat by intraperitoneal injection, urine and faeces were collected. A small amount of (+)-erythro-(4,7-dihydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan and its metabolic product were obtained from an ethyl acetate extract of the urine, and the largest amount of the same metabolic product was obtained from a dichloromethane extract of the faeces. The sole metabolic product was identified as (+)-(4-hydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan by spectroscopic methods. Furthermore, biotransformation of (+)-erythro-(4,7-dihydro-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan by intestinal bacteria in rat faeces was also investigated in vitro. Consequently, (+)-erythro-(4,7-dihydroxy-3-methoxy-1'-allyl-3',5'-dimethoxy)-8-O-4'-neolignan was reduced to the same metabolic product and no other metabolic products were produced. These results suggested that intestinal bacteria were concerned in the specific dehydroxylation of (+)-erythro-(4,7-dihydroxy-3-methoxy-1'-allyl-3'-5'-dimethoxy)-8-O-4'-neolignanin rats.