AKTIVITAS ANTIOKSIDAN EKSTRAK DAUN, BATANG DAN BUAH PARE (Momordica charantia L.) DENGAN METODE 2,2-DIFENIL-1-PIKRILHIDRAZIL (DPPH) DAN FERRIC REDUCING ANTIOXIDANT POWER (FRAP)

• Main Author: Dyah Susilawati, Ramadhani
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/45544
• Institution: Institut Teknologi Bandung

Free radicals are a compound or molecule containing one or more unpaired electrons in its outer orbital. The existence of unpaired electrons cause the highly reactive compounds looking for a partner by attacking and electron binding molecules around. These free radicals are harmfully cause can oxidize nucleic acids, proteins, fats, and even DNA of cells and initiate the onset of degenerative diseases. Antioxidants are defined as substances that are able to delay, slow down, or inhibit the oxidation reaction. Free radicals are known can induce cancer, atherosclerosis, and aging which was caused by tissue damage due to oxidation. Bitter gourd widely used as a medicine and vegetables by Indonesian society. This fruit has been investigated have strong antioxidant activity. There is still little information on the antioxidant activity of other plant organs therefore used leaves, stem, and fruit in this study. The objectives of this research were to determine the antioxidant activity of the leave, stem, and fruit bitter gourd (Momordica charantia) by determining IC50 of DPPH scavenging activity and EC50 of FRAP capacity, total phenolic, flavonoid and carotenoid content, their correlation with the IC50 DPPH and EC50 of FRAP, and correlation between IC50 DPPH and EC50 of FRAP. Extraction was performed by reflux apparatus using three solvents with increasing polarity, namely n-hexane, ethyl acetate and ethanol. Extracts were monitored by thin layer chromatography (TLC) GF254. IC50 DPPH, EC50 FRAP, total phenolic, flavonoid, carotenoid content of each other extract was conducted by ultraviolet-visible spectrophotometry, and their correlation with IC50 DPPH and EC50 FRAP, correlation between IC50 DPPH and EC50 FRAP using Pearson’s method. The highest antioxidant activity was given by the lowest IC50 DPPH (2.87 µg/mL) and the lowest EC50 FRAP which was given by ethyl acetate leaves extract of bitter gourd. The highest of total phenolic, flavonoid, and carotenoid content were exposed by ethyl acetate leave extract (3.05 g GAE/100 g), ethyl acetate leave extract (5.45 g QE/100 g, and n-hexane leave extract (11.32 g BE/100 g), respectively. Total phenolic content in leaves, stem, and fruit extracts of bitter gourd had negative and high correlation with IC50 DPPH and EC50 FRAP while total flavonoid content in leave extract of bitter gourd had negative and high correlation with IC50 DPPH and EC50 FRAP. All of extracts sample (except n-hexane stem extract, n-hexane fruit extract and ethyl acetate fruit extract) were categorized as strong to very strong antioxidant by DPPH method. Phenolic compounds was the major contributor in antioxidant activity of leaves, stem, and fruit extracts of bitter gourd by DPPH and FRAP methods. DPPH and FRAP methods gave linear result in antioxidant activity of leaves, stem, and fruit extracts of bitter gourd (Momordica charantia).