A pyranochalcone and prenylflavanones from Tephrosia pulcherrima (Baker) drumm

A new 2',6'-dimethoxy-4',5'-(2 ',2 '-dimethyl)-pyranochalcone (1) and three known flavanones, namely 5-hydroxy-7-methoxy-8-(3,3-dimethylallyl)-flavanone (methyl glabranin) (2), 5,7-dimethoxy-8-(3,3-dimethylallyl)-flavanone (candinone) (3) and 5-O-methyl obovatin (pongachin) (4), have been isolated from the chloroform extract of the roots of Tephrosia pulcherrima. The flavonoids were fully characterized by detailed 1D- and 2D-NMR spectroscopic investigations. The pyranochalcone 1 showed significant antimicrobial activity when tested against a series of micro-organisms.