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

Abstract

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 µg/g), syringic acid (6.70 µg/g), caffeic acid (4.16 µg/g), ferulic acid (2.06 µg/g), p-coumaric acid (20.22 µg/g), with the highest being gallic acid (74.32 µg/g). Cell cytotoxicity assay of oat polyphenolic extracts revealed that 10 and 15 µg/mL concentrations had non-significant 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 µg/mL concentrations, respectively. In conclusion, oat is a rich source of polyphenols which have strong antioxidant behaviour to suppress the ROS activity.