Biotransformation of furanocoumarins by fungi: preparation of imperation analogs.

Imperation analogs have the furanocoumarin skeleton, with the isopentenyl group, which displayed significant bioactivities. The biotransformation of furanocoumarins imperation, isoimperation and phellopterin (1-3) by fungi has been proved to be an efficient method for the structural modification. Ten transformed furanocoumarin analogs were obtained by fungal biotransformation, including one new highly oxygenated furanocoumarin (4c). Aspergillus niger AS 3.739 displayed selectively transformed capability toward furanocouamrins (1-3) with one or two major products. So, seven hydroxylation and hydrolysis derivatives have been prepared efficiently. Additionally, the biotransformation of phellopterin gave multiple products (4a, 4b, 4c) by Cunninghamella blakesleana AS 3.970. The biotransformation time-courses of furanocoumarins have been established, which suggested the preferred incubation time. The bioactivities of furanocoumarin analogs have been investigated in an in vitro bioassay. And, furanocoumarins 1-3, 2a, and 2c displayed moderate anti-osteoporosis activities using MCET3-E1 cell line at the concentrations of 1, 10, and 100 μM.