Chemical Indices, antioxidant activity and anti-inflammatory effect of extracts of the medicinal rice "Njavara" and Staple Varieties: A comparative study

Abstract

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 (1.84 mg/g, 27.16 mg of gallic acid/g, 4.50 mg of quercetin/g, 0.98 mg of catechin/g and 8.77 mg/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 µg/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