ANTIOXIDANT ACTIVITIES OF ARABICA GREEN COFFEE FROM THREE REGIONS USING ABTS AND DPPH ASSAYS

Abstract

ABSTRACT Objectives: The aim of this research were to determine antioxidant activity from various extracts of arabica green coffee from three different regions using two methods of antioxidant testing which were 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and correlation of total phenolic, flavonoid, and carotenoid content in various extracts of arabica coffee with their IC50 of ABTS and IC50 of DPPH antioxidant activities. Methods: Extraction was conducted by reflux using various polarity solvents. The extracts were evaporated using rotary evaporator. Antioxidant activities using ABTS and DPPH assays, determination of total phenolic, flavonoid, and carotenoid content were performed by UV-visible spectrophotometry and its correlation with IC50 of ABTS and IC50 of DPPH scavenging activities were analyzed by Pearson’s method. Results: The lowest IC50 of ABTS scavenging activity 3.47 µg/ml was given by n-hexane extract of Toraja arabica coffee, while ethanolic extract of Lintong arabica coffee gave the lowest IC50 of DPPH scavenging activity 0.7 µg/ml. Ethanolic extract of Madailing arabica coffee gave the highest phenolic content, and its ethyl acetate extract had the highest total flavonoid. There were negative and high correlation between phenolic content and carotenoid content in Lintong arabica coffee extract with their IC50 of DPPH. Conclusions: All of the arabica green coffee extracts from three regions except LIN1 by ABTS method were categorized as a very strong antioxidant and except TOR1 for DPPH method. Phenolic and carotenoid compounds in Lintong arabica coffee extracts were the major contributor in IC50 of DPPH scavenging activities. Arabica coffee extracts from Lintong showed the linear result in ABTS and DPPH assays. Keywords: Antioxidant, 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, Arabica green coffee, Phenolic, Flavonoid, Carotenoid.