Antioxidant and antiglycation properties of different solvent extracts from Chinese olive (Canarium album L.) fruit

Objective: To evaluate the antioxidant activity, antiglycation property, and bioactive components content of different solvent extracts from Chinese olive (Canarium album L.) fruit. Methods: The dry powder of Chinese olive fruit was extracted with different solvents, i.e., water, water/ethanol (1/1, v/v), ethanol, methanol, acetone and ethyl acetate. The total phenolic, total flavonoids and total triterpenoids contents of various extracts were determined by spectrophotometric methods. Phenolic compounds were identified by high performance liquid chromatography. The assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl- hydrazyl (DPPH) and nitrite oxide methods, chelating activity on metal ions, lipid and protein peroxidation methods. In vitro glucose-bovine serum albumin assay was used to evaluate the antiglycation of various extracts. Results: The water/ethanol extracts of Chinese olive fruit exerted significant scavenging effects on free radicals and strong inhibitory effects on advanced glycation end products formation. The Chinese olive fruit extracts were rich in phenolic compounds and triterpenoids. Gallic acid, ferulic acid and rutin were identified from the water/ethanol extracts. Correlation analysis indicated that there was a linear relationship between the antioxidant potency, free radical scavenging ability and phenolic compounds content of the Chinese olive fruit extracts. Conclusions: Chinese olive fruit could be a natural candidate for studies of dietary complement to diabetes treatment since it combines antioxidant and antiglycation activities.