Characterization of phenolic compounds and antioxidant activity in sorghum [Sorghum bicolor (L.) Moench] grains

Among cereals, sorghum, a gluten-free cereal is a rich source of bioactive polyphenols and dietary antioxidants. Sorghum polyphenolic compounds were characterized and quantified in five sorghum genotypes by high performance liquid chromatography. Grain samples of five sorghum genotypes were grounded and subjected top extraction for profile of polyphenols via High Performance Liquid Chromotography. Results showed that red and brown pericarp genotypes had higher total proanthocyanidin and total phenolic content, therefore, resulting in overall high antioxidant activities. The phenolic acids that showed the higher antioxidant activity in red (SSG 59-3) and brown (G-46) genotypes were caffeic acid, taxifolin and apigeninidin. SSG 59-3 (20.55 +/- 0.11(a), 45.66 +/- 0.23(b), 15.34 +/- 0.10(C)) had higher antioxidant activity evaluated by DPPH, ABTS and FRAP assay. The concentrations of the sorghum-specific 3-deoxyanthocyanidins luteolinidin and apigeninidin were higher in red sorghum. Correlation analysis showed that antioxidant activity had a linear relationship with their polyphenols. Thus, our findings indicated that there is cumulative effect of both high antioxidant activity and phenolic compounds which may be exploited for human food to improve the nutritional value and health properties.