Macrotyloma uniflorum (horse gram, kulthi bean, hurali, Madras gram ) is one of the lesser known beans. The horse gram is normally used to feed horses, though it is also commonly used in cooking. In traditional Ayurvedic cuisine, horse gram is considered a food with medicinal qualities. It is prescribed for persons suffering from jaundice or water retention and as part of a weight loss diet. Although rich in proteins (20%), due to less acceptable taste and flavor of cooked products, it is consumed only by the farming community and low-income groups. Thus, it has remained an underutilized food legume. Horse Gram is mainly cultivated in India. It is also cultivated in Sri Lanka, Malaysia, West Indies etc. In India, this is grown in the states of Karnataka, Andhra Pradesh, Orissa, Tamil Nadu, Madhya Pradesh, Chhattisgarh, Bihar, West Bengal, Jharkhand and in the foot hills of Uttaranchal and Himachal Pradesh. It is consumed as a whole seed, as sprouts, or as whole meal in India, popular in many parts of India. Medical uses of these legumes have been discussed.
Horse gram and moth bean are legumes of the tropics and subtropics, grown mostly under dry-land agriculture. The chemical composition is comparable with more commonly cultivated legumes. Like other legumes, these are deficient in methionine and tryptophan, though horse gram is an excellent source of iron and molybdenum. Comparatively, horse gram seeds have higher trypsin inhibitor and hemagglutinin activities and natural phenols than most bean seeds. Natural phenols are mostly phenolic acids, namely, 3,4-dihydroxybenzoic, 4-hydroxybenzoic, vanillic, caffeic, p-coumaric, ferulic, syringic and sinapic acids. Dehusking, germination, cooking, and roasting have been shown to produce beneficial effects on nutritional quality of both the legumes. Though both require prolonged cooking, a soak solution (1.5% NaHCO3 + 0.5% Na
3 + 0.75% citric acid) has been shown to reduce cooking time and improve protein quality. Moth bean is mostly consumed as dhal or sprouts.
Horse gram is a short day, twining, succulent, annual climbing herb which has trifoliate leaves, white coloured flowers, long linear pubescent pods with curved beak, flattened small seeds with light red, brown, grey, black or mottled testa with photo and thermo-sensitive nature. It matures in 4 to 6 months. Horse gram germinates reasonably well in drought-prone areas with very poor soils (where other crops invariably fail to grow) due to Dehydrins (MuDHN1, MuDHN2 and MuDHN3) which appeared to be the principle stress responsive genes in various abiotic stresses besides, it is relatively tolerant to low to moderate salinity levels with pH up to 8 and heavy metal stresses compared to other pulse crops grown in semi-arid regions. However, it is sensitive to becoming waterlogged, and is completely intolerant of frost (Jones, 1969). Drought tolerance capacity of horse gram is attributed in parts to various pathways like antioxidant and osmolyte biosynthesis, making it sturdy enough to withstand long periods of drought with minimum management. It also exhibits amazing defense against attack by pests/pathogens and the possible source of the indomitable pest resistance may be due to a dual function protein that exhibits both lectin and lipoxygenase like functions. The crude extracts of horse gram plant possess compounds with antimicrobial properties with a broad spectrum of activity against both gram-positive and gram-negative bacteria and fungi