(-)-phaseolin A prenylated member of the class of pterocarpans and an organic heteropentacyclic compound that is 2,3,6b,12b-tetrahydro-1H,7H-chromeno[6',5':4,5]furo[3,2-c]chromen-10-ol in which both of the hydrogens at position 3 have been replaced by methyl groups (the R,R stereoisomer). It is found in found in the seeds of Phaseolus vulgaris (French bean) and in the stems of Erythrina subumbrans. pterocarpans