Fabceae is a chemically very versatile family with non-protein amino acids (more than half of reported n.p. amino acids are from this family) and phytoalexins as defensive compounds, characteristic lupinane type alkaloids and isoflavonoids esp. Rotenones. Other characteristic features are herbaceous habit, root nodules, papilionaceous flowers and diadelphous condition (9-united stamens forming a boat shaped open sheath carrying nectar) and legume fruit. This is a large family of 440 genera containing 12000 species.
Uses
This family provides all the pulses (protein source), oils, medicinal plants, biopesticides, natural dyes, biofuel and timber,
1. Pulses
Pulses form the single largest source of proteins. They always provide all essential amino acids Which the human body cannot synthesize on it’s own). They are also easily digestible because water soluble albumins and globulins always predominate ( about 80%) over prolamines and glutelins in legume seeds. Although the ratio of globulin to albumin varies in different seeds globulins are the major proteins. In Vicia faba, 80% of the total protein consists of globulins and albumins while glutelins form 15% and prolamines less than 5%. This ratio is closely followed in majority of pulses.
Legume proteins are large molecules containing uncommon aminoacids at times. Peanut protein arachin contains sarcosine; mung bean cytochrome c contains e-trimethyl lysine and hydroxy proline in bulk protein of various pulses. Most of the proteins in pulses are globular proteins and vary from 12,000 to several million in molecular weight. Jack bean urease, one of the bigger proteins, has a molecular weight of several millions and is a polymer of many monomeric polypeptides. A single polypeptide may contain upto 700 aminoacid resides.
The storage proteins of pulses occur as aggregates, aleurone grains or protein bodies. All these proteins are characterised by large amounts of aspartic acid, glutamic acid, leucine, basic aminoacids and amides. The abundance of basic aminoacids and amides clearly indicates the function of these proteins as nitrogen reserves. Vicilin and legumin are two common storage proteins of Pisum sativum and Vicia faba with a mol. weight of 186,000 and 331,000 respectively. The majority of storage proteins (excepting vicilin and legumin) contain two distinct major components with sedimentation coefficients 7s and 11s resp. These compounds show reversible dissociation/association. Some proteins have a smaller component of 2s along with a larger component of 15-18s. The major storage proteins of Arachis and Glycine are named as arachin and glycinin respectively.
The important pulses
1. Pea (Pisum sativum Linn.), Peas contain about 20% protein, 56-60% carbohydrates, 1.4% fat, 2.4% minerals, and are a rich source of niacin and riboflavin. The pea plants are often used as forage. U.S.A. & China lead in the production of Peas.
2, Chickpea (Cicer arietinum Linn.), Chickpeas Contain 17-18% protein, 5-6% fats and more than 60% of carbohydrates The seeds are rich sources of minerals like phosphorus, iron, calcium and vitamin C. The seeds are used as such for human consumption or as a substitute of coffee seeds.
3. Kidney beans (Phaseolus vulgaris Linn.) The immature pods (string or snap beans) are used as such while the unripe seeds and ripe dried seeds are cooked before consumption. The seeds contain about 23% protein, 61% carbohydrates and 2-3% fats.
4. Lima beans(Phaseolus limensis Macf.), Lima beans are very nutritious and are often used as a substitute of meat in the diet. It contains 15-25% proteins, 50-55% carbohydrates, 2% fats and a number of vitamins. The seeds are used fresh or dry.
5. Green gram (P. aureus Roxb.), The fresh pods are much in demand as a vegetable. The dry seeds contain 27% protein, 57% carbohydrates, 3.5% fats and good amounts of riboflavin, iron, phosphorus and calcium. The seeds are eaten as such or as "bean sprouts" (4 day old germinated seeds). The decoctions of seeds are used medicinally for the treatment of colic.
6. Black gram (P. mungo Roxb.), The protein content of the seed is 24%. Also present in the seed are 59% carbohydrates and 1.5% fats. Black gram is a fairly rich source of niacin, riboflavin, calcium and phosphorus.
7. Moth bean (P. Aconitifolius Jacq.), The seeds contain 24% proteins, 6% carbohydrates, 1% fat and 3.5% of minerals. It is a rich source of phosphorus, calcium and iron.
8. Pigeon pea (Cajanus cajan Linn), The protein and carbohydrate contents of seeds are 23% and 60% respectively. The seeds are rich in carotenes. phosphorus, calcium, iron and vitamins (excepting vitamin C).
9 Lentil (Lens culinaris Medik.), considered being the most nutritious of pulses is having the following chemical composition; proteins, 25-28%, carbohydrates 60%, minerals 2%, and less than 1% fats. The seeds are rich sources of vitamins A & B and minerals calcium, phosphorus and iron.
10. Lablab (Dolichos lablab Linn.)The chemical constitution of seeds are : 28-30% proteins, 56-60% carbohydrates, 2.5% minerals and rich amounts of carotenes, thiamine and vitamin C.
2. Oil seeds
1. Soybean (Glycine max Merr. ) The seeds contain about 35% carbohydrates including free sugars like sucrose (50%), stachyose (35%), etc.; 45-50% protein, 20% fixed oil, saponins and an enzyme urease. The oil cosists of glycerides of linoleic (50%), oleic (30-35%), linolenic (5-6%) palmitic (6%), stearic (4%) acids and traces of arachidic acid and stigmasterol.
Soybeen oil is used in varnishes, insulators and, after refining, as a cooking oil or for the prepartion of margarine. The oil is a commercial source of lecithin and stigmasterol. The oil cake contains 40-50% protein and 8-10% fat, and is used as a livestock feed and in the preparation of plastics, synthetic textile fibres etc. Soybean is well-known for the many isoflavone glycosides present such as genistein, diadzin (glycitein 7-O-β-D-glucoside), glycitin, 6’’-O-acetyl genistein, 6’’-O-acetyl diadzin and their aglycones, and 6-O-malonylated derivatives of diadzin, glycitin and genistein also are found to be present. Genistein, diadzin and their derivatives form 0.25% of the defatted meal. Other compounds present are six kinds of group A saponins Aa, Ab, Ac, Ad, Ae and Af giving soyasapogenol A as aglycone and 5 groups of B saponins, Ba, Bb, Bc ( all three giving soyasapogenol B as aglycone), Bd and Be (soyasapogenol E).
Soybean oil (Refer oils) is known to decrease thrombosis and found useful in treating cholethiasis. Soymilk is useful in treating acute diarrhoea (in infants) and atherosclerosis. Isoflavones are estrogenic and therefore are useful in treating breast cancer. This is done through preventing effect of protein tyrosine kinase (PTK) activity. Some other effects of genistein are inhibition of topoisomerase 2 and accumulation of protein associated single strained breaks of DNA in the whole cell. Genistein is also reported to prevent leukemia and prostate cancer by arresting cell cycle, including apoptosis, modifying cellular differentiation programme and by modulating cell-cycle events. Genistein-induced apoptosis of prostrate cancer is preceded by a specific decrease in total adhesion kinase activity. Use of genistein is found to prevent incidence of cancer of colon, lung, liver, oesophagus, oral epithelium and bone marrow.
2. Ground nut (Arachis hypogea Linn.) The kernels contain more than 45% fixed oil, 20-25% protein and a high amount of thiamine. The oil is light golden yellow in colour and has a nutlike odour. The percentage of fatty acids in the oil are 56-60% oleic, 20-25% linoleic, 8% palmitic, 3-4% stearic and 7- 8% higher fatty acids like arachidic, behenic and lignoceric acids.
Lectins, Toxic proteins
Lectins/Phytohemagglutinins – a group of glycoproteins which agglutinates erythrocytes, and thus are highly toxic are present in some seeds of economic importance. Abrin (in Abrus), Crotin (in Croton tiglium), ricin (in Ricinus) and soyin (in Glycine max) are some of the important members of this group. Structurally many of these proteins are globulins. Similar toxic proteins of low toxicity are reported from species of Phaseolus, Ervum, Pisum and Vicia.
3. Timbers
1 Indian rosewood (Dalbergia latifolia Roxb.)
A tall deciduous tree, the wood of which is one of the most valuable timbers of India. The wood is dark nut brown to blackish purple with white or purplish veins and streaks of lighter colour. It is finegrained, extremely strong, heavy, easily worked and is extensively used for furniture, carvings etc.
2. Sissoo, South Indian Redwood (Dalbergia .sissoo Roxb.)
Sissoo is one of the most important Indian timbers obtained from a large tree. The wood is brown, very hard, mottled with darker veins, close-grained, durable, seasons well and does not warp or split. It is esteemed highly for all purposes, where strength and elasticity are required and used extensively in furniture, boat building and construction work. This wood is said to be the finest for carving.
Source :
Useful Herbs of the Planet Earth, M. Daniel, (2012), Scientific Publishers,\ Jodhpur, Pages 710, Rs. 2050/- (Hard bound); Rs. 525/- (Paper bound)
Note:
Medicinal plants, Biopesticides and Biofuel from this family will be treated in second part
Mammen Daniel
