Dimethylchromene rotenoids from Tephrosia candida

The hexane and ethyl acetate extracts of roots of Tephrosia candida afforded a new rotenoid, 12a-hydroxy-beta-toxicarol, together with a series of known ones, identified as: deguelin, alpha-toxicarol, tephrosin, 6a,12a-dehydrodeguelin, 12a-hydroxy-alpha-toxicarol, 6a,12a-dehydro-alpha-toxicarol and 6a, 12a-dehydro-beta-toxicarol. The possibility of four of these rotenoids to be linear or angular is discussed on the basis of HMBC experiments. Angular rotenoids are very common, however the linear are restricted, and to the best of our knowledge only two linear dimethylchromene rotenoids are described in the literature. (C) 1997 Elsevier Science Ltd.