Effect of pH during Extraction on the Antioxidant and Antiglycated Activities of Polysaccharides from Opuntia Ficus Indica

Abstract : The extraction of carbohydrates from Opuntia ficus indica cladodes at different pH was carried out by ultrasound followed by ethanol precipitation and dialysis. The extraction yields ranged from 4.6 to 24.5%. The highest content in galacturonic acid was observed for the acidic extract (37.4%). On high‐performance size exclusion chromatography, the average molecular weight of all extracts ranged from 7,500,000 to 9,610,000 g/mol. The antioxidant activity of extracted polysaccharides was tested by three assays (1,1‐diphenyl‐2‐picryl‐hydrazil radical scavenging assay, Nitric oxide radical scavenging assay and Linoleic acid peroxidation). The glucose‐induced advanced glycation end‐product (AGE) formation of all extracts was also carried out using in vitro galactose–bovine serum albumin assay. Results showed that the acidic extract exhibited even better antioxidant capacity and inhibitory effect of AGE formation.