Rice - not just a staple food: A comprehensive review on its phytochemicals and therapeutic potential

Abstract Background Rice (Oryza sativa L.) is the most popular staple food grain and an important source of fibre, energy, minerals, vitamins, and other biomolecules. Rice parts exhibited a number of health beneficial effect in pre-clinical/clinical studies. Rice constituents are getting popularity in preparation of pharmaceutical adjuvant, food additives and supplements. Scope & approach In this paper, we summarized the available literature on health-promoting and therapeutic activity of rice and rice biomolecules, and biomolecules, along with the scope of rice in pharmaceutical and food industry. In addition, we discussed the possible molecular mechanisms of action of the rice/rice part/biomolecules. Key findings Vitamin E, γ-oryzanol, phenolic acids (i.e. ferulic acid, gallic acid, syringic acid), anthocyanin and proanthocyanidin (i.e. epicatechin, cyanidin-3-O-glucoside), flavonoids (i.e. quercetin, apigenin, kaempferol, tricin), carotenoids (i.e. lutein, zeaxanthin, β-carotene) and phytosterol (i.e. stigmasterol, β-sitosterol) are some key rice biomolecules. Promoting endogenous antioxidants, scavenging free radicals, suppression of inflammatory/pro-inflammatory cytokinins (i.e. interleukin 6, cyclooxygenase, tumor necrosis factor, NOS) are some key antioxidant, anti-inflammatory mechanism of rice biomolecules. Rice bran cause apoptosis, inhibit DNA synthesis of cancer cell. Rice bran and biomolecules found effective against diabetes by enhancing insulin release and glucose uptake, inhibiting β-cell destruction, insulin resistance, carbohydrate metabolizing enzyme and AGE formation. Rice bran/rice bran oil enhanced LDL receptor, CYP7A1, SREBP-2 and excretion of faecal cholesterol and bile acid, while reduced cholesterol absorption, HMG-CoA reductase, fatty acid synthase. Rice and its biomolecules also exhibited nephroprotective, neuroprotective, GIT protective activity. Rice starch is getting importance in the pharmaceutical industry as an adjuvant.