CHEMICAL INDICES, ANTIOXIDANT ACTIVITY AND ANTI-INFLAMMATORY EFFECT OF EXTRACTS OF THE MEDICINAL RICE "NJAVA']JAVARA" AND STAPLE VARIETIES: A COMPARATIVE STUDY

Chemical indices, antioxidant and anti-inflammatory activity of extracts of bran of medicinal rice - Njavara black glumed type (NBb) and its rice (NBr), were studied in comparison with bran and rice of staple varieties: Sujatha and Palakkadan Matta. Total oryzanol, phenolic, flavonoid, proanthocyanidin and phytate contents of NBb (1.84mg/g, 27.16mg of gallic acid/g, 4.50mg of quercetin/g, 0.98mg of catechin/g and 8.77mg/g dry weight of bran, respectively) were higher compared with NBr and staple varieties. NBb showed greater reducing power and significantly higher scavenging activity with 2, 2-diphenyl-1-picryl hydrazyl radical, superoxide and hydrogen peroxide with values of concentration of NBb required to scavenge 50% of respective radicals (IC50): 84.66, 203.16 and 73.55 mu g/mL, respectively. The anti-inflammatory effect (in vivo) of NBb was 83.3%, whereas NBr and staple varieties showed activity in the range 16-66%. The higher oryzanol content, chemical indices, antioxidant and anti-inflammatory activity for Njavara compared with staple varieties corroborates with its medicinal use in Ayurveda. PRACTICAL APPLICATIONS Medicinal plants are a source of antioxidants and bioactive compounds responsible for the prevention of oxidative stress that leads to many degenerative diseases and conditions. The present study indicates that the extracts of Njavara (black glumed), a medicinal rice variety, contains significant amounts of oryzanols, phenolic acids, flavonoids, proanthocyanidins and phytic acid compared with staple varieties. These extracts are potential free radical scavengers and have anti-inflammatory effect compared with staple varieties. Njavara, identified as a source of bioactive compounds, can be consumed as a health food in addition to its medicinal uses; thus, benefiting consumers. Higher oryzanol content in Njavara is beneficial for lowering plasma cholesterol, reducing platelet aggregation, nerve imbalances and aortic fatty streak formation. Higher antioxidants in Njavara are also beneficial against the diseases initiated by free radicals. These promising results also open up newer areas of research for developing improved varieties of rice containing more bioactive compounds.