ANTIOXIDANT ACTIVITY OF EXTRACTS FROM FIVE CITRUS SP. PEELS USING DPPH AND CUPRAC ASSAY AND ITS CORRELATION WITH TOTAL PHENOLIC, FLAVONOID, CAROTENOID CONTENT

• Main Author: Nurfitri, Hadianti
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/78914
• Institution: Institut Teknologi Bandung

Antioxidant can prevent oxidative stress that could trigger degenerative diseases. Many studies said that Citrus have high antioxidant capacities due to its phenolic and flavonoid content. The objectives of this research were to determine antioxidant activities by calculating IC50 of DPPH (2, 2-diphenyl-l-picrylhydrazyl) scavenging activity and EC50 of CUPRAC (Cupric ion Reducing Antioxidant Capacüy) capacity; determine total flavonoi& phenolic, and carotenoid content in various extracts of five Citrus peels; analyze the correlation between total flavonoid, phenolic, and carotenoid content with IC50 DPPH and EC50 CUPRAC; and correlation IC50 DPPH and EC50 CUPRAC. Extraction was perfonned by reflux using three diferent polarities of solvents, n-hexane, ethyl acetate, and ethanol, respectively. Extracts were monitored by thin layer chromatography (TLC). Antioxidant activity of each extract was tested using DPPH and CUPRAC assays to determine of IC50 of DPPH, EC50 of CUPRAC, determination of total phenols, flavonoid, and carotenoid content were performed by spectrophotometry UV-Vis and their correlation with IC50 of DPPH and EC50 of CUPRAC, and correlation between IC50 of DPPH and EC50 of CUPRAC by Pearson's method. Ethyl acetate extract of C.smensis peels (M2) had the lowest ICS() of DPPH scavenging activity 11.04 gg/mL, while n-hexane extract of C.sinensis peels (Ml) had the lowest EC50 of CUPRAC capacity 22.93 gg/mL. Ethyl acetate extract of C. sinensis (M2) the highest total phenolic content (431.3 mg GAE/IOO g), Ml had the highest total flavonoid content (2,037.1 mg QE/IOO g), and the highest total carotenoid content (509.5 mg BE/ 100 g). Total phenolic content in C. aurantifolia peel extracts had negative and high correlation with their DPPH and EC5() CUPRAC. The DPPH of C. aurantifolia, C. limon, C. maxima, C. sinensis peel extracts gave linear result with EC5() CUPRAC. All of citrus peel extract (except ethanol extract of C. aurantifolia) were very strong antioxidant by DPPH method. Phenollc compounds were major contributor in antioxidant capacity of C. aurantifolia by DPPH and CUPRAC methods. DPPH and CUPRAC assays gave linear correlation for antioxidant activity in C. aurantifolia, C. limon, C. maxima, C. sinensis peel extracts.