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.