ANTIOXIDANT ACTIVITY FROM PEEL EXTRACTS OF FOUR VARIETIES OF RAMBUTAN (Nephelium lappaceum L.) WITH DPPH AND FRAP METHODS

• Main Author: Indah Sari, Putri
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/45358
• Institution: Institut Teknologi Bandung

Background and objectives: Degenerative diseases growing rapidly with the times that was caused by free radicals. Antioxidant is a substance which can avoid the negative impact of free radicals because it can inhibit oxidation process of free radicals. Rambutan (Nephelium lappaceum L) is one of the fruits widely spread in Indonesia derived from Sapindaceae. According to several studies, rambutan is one of plants which has high potential in antioxidant activity. The aims of this research were to determine antioxidant activity from various peels extract of four varieties of rambutan with DPPH (2-2-diphenyl-1-picrylhydrazyl), FRAP (Ferric Reducing Antioxidant Power) methods and the correlation between total phenolic content, flavonoids and carotenoids towards DPPH and FRAP. Method: Extraction process was performed by reflux method using various solvents with different polarity levels. Each extracts was monitored by thin layer chromatography (TLC). The antioxidant activity of each extract were conducted by DPPH and FRAP. In addition, also performed determination of IC50 of DPPH scavenging activity and EC50 of FRAP capacity, total phenolic content, total flavonoids and total carotenoids of each extract by ultraviolet-visible spectrophotometry and its correlation with DPPH and FRAP using Pearson’s method. Results: The highest antioxidant activity with DPPH method (93.71 ± 0.54 %) was given by ethanolic peel extract of lebak bulus rambutan and for FRAP method (43.72 ± 1.11 %) was given by ethyl acetate peel extract of lebak bulus rambutan. Ethyl acetate extract of lebak bulus rambutan had the lowest IC50 of DPPH scavenging activity which was 3.50 µg/mL and ethyl acetate extract of binjai rambutan had the lowest EC50 of FRAP capacity 77.12 µg/mL. The highest total fenolic content was shown by ethyl acetate extract of lebak bulus rambutan (40.9 ± 2.20 g GAE/100 g), n-hexane extract of binjai rambutan had the highest total flavonoids (3.46 ± 0.34 g QE/100 g), and the highest total carotenoid was found in n-hexane extract of rapiah rambutan (0.61 ± 0.02 g BE/100 g). Conclusion: Total fenolic content of rambutan peel extracts had positive and significant correlation with their DPPH scavenging activity and FRAP capacity (p<0.01). Fenolic compounds in peel extracts of four varieties of rambutan were the major contributor in DPPH scavenging activity and FRAP capacity. DPPH scavenging activities of peel extracts of four varieties of rambutan had linear result with their FRAP capacities.