Pumilanol, an antiprotozoal isoflavanol from Tephrosia pumila

A novel isoflavan-4-ol (pumilanol), ( re l)-3β-(2′-hydroxy-4′,5′-methylenedioxyphenyl)-6-methoxy-4α,7-dihydroxybenzo-3,4-dihydropyran ( 1 ) and two known flavonoids, tephrinone ( 2 ) and rotenone ( 3 ) together with lupeol and stigmasterol were isolated from the roots of Tephrosia pumila (Fabaceae) from a collection made in Andhra Pradesh, India. The structures of the compounds were determined by MS, 1D and 2D-NMR spectral analysis. Pumilanol ( 1 ) exhibited significant antiprotozoal activity against T. b. rhodensiense , T. cruzi and L. donovani with IC 50 of 3.7, 3.35 and 17.2 μg/mL, respectively, but displayed high toxicity towards L-6 (IC 50 of 17.12 μg/mL) rat skeletal myoblasts.