HPLC analysis of white lupin isoflavonoids

An investigation of the HPLC analytical conditions for simple isoflavone, p renylated isoflavones and some of their glucosyl derivatives resulted in re asonable separation and total elution in 35 min when using a reversed-phase C-18 Lichrospher column and a gradient elution system of MeCN-THF-H2O. Thi s method was successfully applied to quantify the changes in isoflavonoid c onstituents in white lupin (Lupinus albus L.) tissues: (a) young legumes (p ods and seeds) during maturation, and (b) soaked, germinating seeds. In dev eloping legumes, genistein and 2'-hydroxygenistein, as well as their prenyl ated derivatives, were present in the pods as the major components, togethe r with minor amounts of glucosides, whereas only minute amounts of isoflavo noids were detectable in the ripening seeds. When soaked with water, mature lupin seeds which normally contain trace amounts of isoflavonoids, started rapidly to biosynthesize simple isoflavones and accumulate large amounts o f genistein 7-O-glucoside and its 6 "-O-malonyl derivative. These dynamic c hanges are discussed in relation to the role of isoflavonoids in the lupin defense system.