Extraction, identification and assessment of antioxidative compounds of bran extracts of traditional rice cultivars: An analytical approach

•Methanol extracts of rice bran had higher TPC as compared to acetone & ethanol extracts.•TFC & TAC were higher in acetone extracts of bran followed by ethanol & methanol extracts.•Thymol, quinicquinic-caffeicacidester, dicaffeoylquinic acid accounted higher DPPH activity.•High lipid peroxidation inhibition was due to presence of high hydrophilic phenolic compounds.•Multiple-OH phenols, flavonoid & hydracinammic acid in bran contributed to higher reducing power. The antioxidative compounds were extracted by ultrasonic treatment of bran extracts of seven pigmented (completely) and non pigmented (sparsely) colored rice cultivars followed by assessment of their in vitro antioxidative capacity by LC-MS and oxidation/reduction assay based methods. A total of 40-compounds, 7-phenolic, 9-flavonoids, 9-hydroxycinammic acid derivatives, 3-hydroxybenzoic acid derivatives and other glucosides specifically, pro-anthocyanidin trimer and procyanidin-B1 (dimer) were indentified in completely colored rice cultivars. Higher DPPH radical scavenging activity of pigmented cultivars was due to higher percentage of phenolics like thymol, quinicquinic-caffeicacid ester and polar dicaffeoylquinic acid; whereas higher lipid peroxidation inhibition was attributed to the presence of polar substances such as p-hydroxybenzoicacid, procyanidin B1 and quercetin-3-O-rutinoside. The phosphomolybdenum reduction capacity was attributed to luteolin-7-O-glucoside, apigenin-7-O-glucoside, caffeicacid, myrecitin and phloreticacid. Whereas, grater reducing power of pigmented bran was attributed to presence of multiple-OH groups containing phenols, flavonoid and hydracinammicacid depicting potential health and nutritional effects of these rice cultivars.