Phenolic acid profile of oat cultivars, and their suppressive effect on intracellular reactive oxygen species

Oat ( Avena sativa L.) has rich phenolic contents with nutritional and therapeutic health benefits. The objective of the present work was to perform a cell cytotoxicity assay of three South Asian oat cultivars to determine their suppressive effect on intracellular reactive oxygen species (ROS). Oat cultivars were firstly examined for total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, and phenolic acid profiling through HPLC. Total phenolic contents of oat cultivars ranged from 167.57 to 198.41 mg GAE/100 g, and DPPH scavenging activity was IC50 = 18.81 to 13.18 mg/mL. Oat cultivars displayed average content of phenolic acids such as vanillic acid (0.33 mu g/g), syringic acid (6.70 mu g/g), caffeic acid (4.16 mu g/g), ferulic acid (2.06 mu g/g), p-coumaric acid (20.22 mu g/g), with the highest being gallic acid (74.32 mu g/g). Cell cytotoxicity assay of oat polyphenolic extracts revealed that 10 and 15 mu g/mL concentrations had nonsignificant differences when compared with their respective control treatments. Oat extracts suppressed ROS in Caco-2-cells, with or without hydrogen peroxide stimulation from 65.20 - 86.13%, and 56.36 - 79.56% with 10 and 15 mu g/mL concentrations, respectively. In conclusion, oat is a rich source of polyphenols which have strong antioxidant behaviour to suppress the ROS activity.