#TITLE_ALTERNATIVE#

• Main Author: RAHMAWATI NIM : 10714099, ANNISA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25678
• Institution: Institut Teknologi Bandung

Free radicals are atoms, molecules, or compounds that have unpaired electrons that are reactive and <br /> <br /> can attack and bind to molecular electrons that surround it. At high concentrations, free radicals can <br /> <br /> cause various disorders in the body, such as cell function disorder, cell structure damage, modified <br /> <br /> molecules that can not be recognized by the immune system and mutations. The negative effects of <br /> <br /> free radicals can be reduced by antioxidants. Antioxidants inhibit the oxidation reaction due to free <br /> <br /> radicals. Antioxidants can be found in a variety of plants, such as bilimbi (Averrhoa bilimbi L.). The <br /> <br /> objectives of this research were to study antioxidant activity of leaves, fruit and twigs of bilimbi by <br /> <br /> determining IC50 DPPH (2,2-diphenyl-1-picrylhydrazyl) and IC50 ABTS [2,2'-azino-bis (3- <br /> <br /> ethylbenzothiazoline-6- sulphonic acid)]; total phenolic and flavonoid content; analyze the correlation <br /> <br /> between total phenolic and flavonoid with IC50 DPPH and IC50 ABTS, and also analyze the correlation <br /> <br /> beetwen DPPH and ABTS in sample extracts. Extraction was conducted by reflux using increasing <br /> <br /> polarity solvent, e.g. n-hexane, ethyl acetate, and ethanol. Determination of IC50 DPPH, IC50 ABTS, <br /> <br /> total phenolic and flavonoid content of each extract were performed by spectrophotometry uvvisible. Correlation of total phenolic and flavonoid content with their IC50 of DPPH and IC50 of ABTS <br /> <br /> and also correlation of two methods were conducted by Pearson method. Antioxidant activities of <br /> <br /> leaves, fruits and twigs extracts of bilimbi gave IC50 DPPH in the range of 2.03 –29.26 µg/mL, <br /> <br /> meanwhile IC50 ABTS 0.91-83.03 µg/mL. The highest total phenolic content and total flavonoid <br /> <br /> content was given by the ethyl acetate leaves extract of bilimbi (11.48 g GAE / 100 g and 6.51 g QE / <br /> <br /> 100 g, respectively). Total phenolic content in leaves and twigs extracts of bilimbi had negative and <br /> <br /> significant correlation with their IC50 DPPH and significantly negative correlation with IC50 ABTS of all <br /> <br /> sample extracts. IC50 DPPH leaves and twigs extracts had signicantly positive correlation with their IC50 <br /> <br /> ABTS. All organs extracts of bilimbi were categorized as very strong antioxidant by DPPH method, <br /> <br /> hence it was potential to be developed as source of natural antioxidant. Phenolic compounds were <br /> <br /> the major contributors in antioxidant activity of leaves and twigs extracts of bilimbi by DPPH method <br /> <br /> and major contributors in antioxidant activity of all extracts of bilimbi by ABTS method. DPPH and <br /> <br /> ABTS methods gave linear result in antioxidant activity of leaves and twigs extracts of bilimbi. <br />