Phenolic and polyphenolic profiles of chia seeds and their in vitro biological activities

Phenolics exist in the soluble and insoluble-bound forms. In this research, free, esterified and insoluble-bound phenolics of defatted chia seeds were evaluated for their antioxidant activity using in vitro methods, namely ABTS+, DPPH and HO scavenging capacity assays. Their effect in a β-carotene linoleate system, reducing power and metal chelation activities were also determined. Furthermore, inhibition of activities against pancreatic lipase, α-glucosidase as well as LDL-cholesterol oxidation as well as DNA damage induced by peroxyl and hydroxyl radicals were examined. The free fraction was the predominant form of phenolics. HPLC-DAD-MS/MS analysis led to the identification of 27 phenolics belonging to phenolic acids, flavonoids and proanthocyanidins. Procyanidin dimers (A, B1, B2, and B3) were identified for the first time. Chia seeds provide a viable source of functional food ingredients or nutraceuticals with protective antioxidant potential, but further research is required to confirm their anti-obesity and anti-diabetic effects.