A Comparative Evaluation of chlorogenic acid content and antioxidant activity in artichoke (Cynara scolymus L.) samples under different storage conditions

Artichoke has been used for a long time in the traditional medicine against dyspeptic complaints and as a liver protector due to its choleretic and cholagogue effects. Chlorogenic acid, the main ingredient of artichoke is known to show hepatoprotector, anticancer, anti-obesity and antioxidant activities. In this study, antioxidant activity and chlorogenic acid quantification were performed using the samples of artichoke as fresh, boiled, frozen, boiled frozen, canned, fresh leaf and dry leaf. Potential antioxidant activity was evaluated using DPPH assay. Flavonoid and phenolic contents were determined by Aluminum chloride colorimetry and Folin-Ciocalteu methods. The amounts of colorogenic acid in the samples were determined by HPLC-DAD system. The results have shown that highest chlorogenic acid content was determined in the 10-minute frozenboiled sample (0.01441 mg/100g), followed by canned (0.01043 mg/100g), 20-minute cooked artichoke (0.001912 mg/100g), fresh artichoke (0.001519 mg/100g) and frozen artichoke (0.0004 mg/100g). The antioxidant activity results have revealed that highest % DPPH capture effect was observed in the cooked artichoke sample (ED50 =1.949 mg/ml). The total flavonoid content was equivalent to quercetin (43.859 mg QE/100g) whereas total phenolic content equalled to gallic acid (14.640 mg GAE/100g). The antioxidant activity and the amounts of colorogenic acid were found to be the highest in the cooked artichoke sample whereas the lowest antioxidant activity observed in canned artichoke. The results show that the heat treatment applied for storage can positively affect the amount of chlorogenic acid and antioxidant activity. (author)