Detection of isoflavonoids in selected representatives of the Solanaceae family

Selected representatives of the Solanaceae family have been tested for the presence of ten isoflavonoids, namely daidzein, genistein, formononetin, isoformononetin, biochanin A, prunetin, daidzin, genistin, ononin and sissotrin. Plant material was obtained in the Botany Garden of Charles University and in Czech University of Agriculture. Following species have been tested: Nicotiana tabacum, N. alata., N. sanderae Hort. , N. glauca Graham , N. silvestris, Lycopersicon esculentum Mill. , Solanum dulcamara L.. Leaves and inflorescence stalks were freeze-died, pulverized and extracted with methanol/water. Extracts were analyzed by HPLC-MS-SIM and by specific immunoassays. Both approaches revealed a spectrum of isoflavonoids, aglycones as well as glycosides, in all Solanaceae plants under study. The concentrations of individual compounds ranged from units of micrograms up to two milligrams per kg (dry weight). Methoxy isoflavones (both types, i.e. 4'-methoxy as well as 7-methoxy) prevailed to non-methylated ones. Prunetin was the most abundant aglycone, followed by formononetin and biochanin A, sissotrin was the most abundant glycoside. Isoflavones were more abundant in the inflorescence than in leaves, the content in stalks was negligible. Traces of individual isoflavones were detected also in tomato jujice. Up to now, the only isoflavonoid described in the Solanaceae was torvanol from Solanum torvum (1). Our data indicate, that isoflavonoid metabolism may occur generally in the Solanaceae. Acknowledgment: This study was supported by the grants MSM6046137305 and GACR 525/06/0864. Reference : 1. Arthan, D. et al. (2002), Phytochemistry 59: 459.