AKTIVITAS ANTIOKSIDAN EKSTRAK DAUN, RANTING, DAN BUAH JERUK NIPIS (Citrus aurantifolia Swingle) DENGAN METODE DPPH (2,2-DIFENIL-1-PIKRILHIDRAZIL) DAN FRAP [FERRIC REDUCING ANTIOXIDANT POWER]

• Main Author: Hoesada, Helbert
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40409
• Institution: Institut Teknologi Bandung

Free radicals are atoms, groups, molecules or compounds containing unpaired electrons in its outer orbit. In normal amounts, free radicals can be beneficial to human health, but in excessive condition free radicals can cause oxidative damage from the cellular, tissue, and body organs. Antioxidants are substances that can prevent or inhibit damage caused by oxidation. Lime (Citrus aurantifolia Swingle) is one plant that contains antioxidant compounds. This study aims to examine the antioxidant activity of leaves, twigs, and fruits extracts of lime using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (Ferric Reducing Antioxidant Power) methods; determine total phenolic and flavonoid; analyze their correlation to IC50 DPPH and EC50 FRAP, and correlation between DPPH and FRAP methods in the test samples. Extraction was carried out by reflux method using solvent with increasing polarity. Determination of IC50 DPPH, EC50 FRAP, total phenolic, and flavonoid was performed by ultraviolet-visible spectrophotometry. Correlation between phenol total, flavonoid total and IC50 DPPH, EC50 FRAP, and two-methods correlation were conducted using Pearson method. IC50 DPPH of leaves, twigs, and fruits extracts of lime in the range of 2.64 - 50.1 µg/mL, while the EC50 FRAP 36.14 - 889.99 µg/mL. The highest total phenolic content was given by ethanol twigs extract of lime (7.29 g GAE/100 g) and the highest total flavonoid content was given by ethanol fruit extract of lime (52.81 g QE/100 g). The phenolic total of twigs extract has a negative and significant correlation with IC50 DPPH and EC50 FRAP. The flavonoid total of leaves extract also had a significant and negative correlation with IC50 DPPH and EC50 FRAP. The IC50 DPPH of all samples did not provide a positive and significant correlation with the FRAP EC50. Phenolic compounds are the main contributors in antioxidant activity of lime twigs extracts with DPPH and FRAP methods. Flavonoid compounds are the main contributors in antioxidant activity of lime leaves extract with the DPPH and FRAP methods. DPPH and FRAP methods do not provide linear results in all test samples.