Abstract Isoflavonoids are a subclass of plant flavonoid metabolites exclusively found in legumes, where they are important compounds mediating multiple plant-microbial interactions. The multiple health-promoting effects of isoflavonoids, especially those of typical soybean isoflavones genistein and daidzein against hormone-related cancers, osteoporosis, menopausal symptoms, and cardiovascular disease have been studied intensively. Isoflavones are secondary metabolites of plant phenylpraponoids pathway, and cloning of genes encoding IFS from several legumes has offered the possibility of genetic engineering to synthesize isoflavones in plants that normally do not yield such metabolites. However, genetic engineering studies have unveiled an integration of complex molecular regulations of isoflavones metabolic pathway.
