COMPARISON OF FIVE ANTIOXIDANT ASSAYS FOR ESTIMATING ANTIOXIDANT CAPACITY FROM THREE SOLANUM SP. EXTRACTS

Abstract

<p>ABSTRACT<br />Objectives: The aims of this research were to determine antioxidant capacity of various extracts from black nightshade, turkey berry, and round<br />green eggplant using five antioxidant assays which were ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC),<br />H<br />2<br />O<br /> scavenging, phosphomolybdenum assay, and beta-carotene bleaching (BCB), correlation of total phenolic, flavonoid, and carotenoid content with<br />their inhibitory concentration 50% (IC<br />2<br />50<br />) and exhibitory concentration 50% (EC<br />) of five antioxidant assay and correlation between five antioxidant<br />assays.<br />50<br />Methods: Extraction was conducted by reflux using gradient polarity solvents. The extracts were evaporated using rotary evaporator. The antioxidant<br />capacity study, determination of phenolic, flavonoid, and carotenoid content were performed by ultraviolet-visible spectophotometry, while its<br />correlation with IC<br />50<br /> and EC<br />50<br /> of five methods were analyzed by Pearson’s method.<br />Results: Ethanolic and ethyl acetate fruit extracts of turkey berry denoted the highest antioxidant capacity using FRAP (EC<br />41.32 µg/ml),<br />H<br />2<br />O<br />2<br /> scavenging assay (IC<br />50: <br />1.01 µg/ml), and CUPRAC (EC<br />117.56 µg/ml). While ethyl acetate fruit extract of round green eggplant gave the<br />highest phosphomolybdenum capacity (EC<br />50<br />50: <br />: 375.47 µg/ml), and ethyl acetate fruit extract of black nightshade showed the highest BCB capacity<br />(EC<br />50: <br />158.66 µg/ml). Phenolic content of all fruit extracts had a tendency to correlate with FRAP and H<br />2<br />O<br /> scavenging antioxidant capacity, meanwhile<br />flavonoid and carotenoid content had a tendency to correlate with CUPRAC, phosphomolybdenum, and BCB antioxidant capacity.<br />2<br />Conclusions: Phenolic compounds were a major contributor in antioxidant capacity of black nightshade, turkey berry, and round green eggplant<br />extracts using FRAP and H<br />2<br />O<br /> scavenging, meanwhile flavonoid and carotenoid compounds were a major contributor in antioxidant capacity using<br />CUPRAC, phosphomolybdenum and BCB assays. FRAP assay had linear correlation with H<br />2<br />2<br />O<br /> scavenging, meanwhile CUPRAC had linear correlation<br />with phosphomolybdenum and BCB.<br />Keywords: Antioxidant, Antioxidant assays, Solanum fruits.<br />2</p><p>50:</p>