A new pterocarpan, (+)-3,4-dihydroxy-8,9-methylenedioxypterocarpan , was isolated from the flowers of Petalostemon purpureus by a DNA strand-scission assay-guided fractionation procedure. Compound 1 demonstrated activity in a standard in vitro DNA strand-scission assay, and cytotoxicity toward a KB tumor cell line. Two other related pterocarpans [2, 3] isolated from same plant were found to be moderately active for KB cells, but were inactive in the DNA strand-scission assay. (+)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan  has not been reported previously as a natural product, while (+)-maackiain  has been isolated only as an optically inactive racemate along with its optical antipode, the (-)-isomer
Isolation and structure identification of an active DNA strand-scission agent, (+)-3,4-di-hydroxy-8,9-methylenedioxypterocarpan
Chaudhuri, S., Huang, L., Fullas, F., Brown, D., Wani, M., & Wall, M. (1995). Isolation and structure identification of an active DNA strand-scission agent, (+)-3,4-di-hydroxy-8,9-methylenedioxypterocarpan. Journal of Natural Products, 58(12), 1966-1969.