Biologically active molecules and nutraceutical properties of legume seeds

The presence of many different types of proteins and other smaller molecules, including alkaloids, isoflavones, polyphenols and a variety of oligosacharides, make legume seeds unique. The recent reappraisal of the effects that grain legume components may have on human well-being is mainly based on experimental evidences that show up their beneficial activity in the prevention and treatment of various diseases. By and large, these results strongly support the claim that regular dietary intake of grain legumes is one of the ways for a healthy life. The detailed description at molecular and biological level of the seed components effects still deserves further studies, as well as the direct trial and assessment of every legume species, including the so-called minor legumes. In this review we analyze the results about proteins, carbohydrates and non-nutrient compounds. Specific grain legume proteins have been directly proved to be responsible for a specific dietary or pharmacological effect. Moreover, bioactive peptides that might prevent diseases related to life-style are released from grain proteins after enzymatic digestion. Many bioactive molecules are considered non-nutrient substances but they certainly exert metabolic effects on human and animals. In this group are included phytates, saponins and phenolic compounds. Among these latter molecules, isoflavones are gaining importance and magnetizing many research efforts, including the investigation of minor legumes, since a variety of pharmacological effects (hypocholesterolaemic, estrogen mimic, endothelian cell proliferation, platelet activation) have been described.