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.
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