ANTIOXIDANT ACTIVITY OF VARIOUS LEAVES EXTRACTS FROM FIVE VARIETES OF RAMBUTAN (Nephelium lappaceum L.) AND ITS CORRELATION WITH TOTAL FLAVONOID, PHENOLIC, CAROTENOID CONTENT

• Main Author: Sukowati, Asih
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/45318
• Institution: Institut Teknologi Bandung

Background and objectives: Degenerative diseases and premature aging are implications of oxidative stress caused by the accumulation of free radicals in the body, therefore the presence of antioxidants is important to neutralize free radicals. Rambutan leaves contained phenolic, flavonoid, tannin and saponin compounds. The aim of this research was to study antioxidant activity of various leaves extracts from five varietes of rambutan using two methods of antioxidant testing which were DPPH (2-2-diphenyl-1- picrylhydrazyl) and ABTS ( 2-2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and its correlation with total phenolic, flavonoid and carotenoid content. Methods: Extraction was performed by reflux using gradient polarity solvent. Each extracts were observed by thin layer chromatography (TLC), antioxidant activity by DPPH, ABTS assay, IC50 of DPPH and ABTS scavenging activity, determination of total phenolic, flavonoid and carotenoid content were performed by spectrophotometry UV-Vis and its correlation with DPPH and ABTS by Pearson’s method. Results: The highest DPPH scavenging activity (94.60 ± 0.002 %) was given by the ethanolic leaves extract of binjai rambutan and the highest ABTS scavenging activity (91.23 ± 0.222 %) was given by the ethanolic leaves extract of rapiah rambutan. Ethanolic leaves extract of rapiah rambutan had the lowest IC50 of DPPH scavenging activity 14.67 µg/mL and 12.83 ?g/mL for ABTS scavenging activity. All of the ethanolic leaves extract from five varieties of rambutan had IC50 < 50 ?g/mL. Ethanolic leaves extract of rapiah rambutan had the highest total phenolic content (29.46 ± 0.039 g GAE / 100 g), the ethyl acetate leaves extract of pagar rambutan had the highest total flavonoid content (9.59 ± 0.046 g QE / 100 g) and hexane leaves extract of pagar rambutan had the highest total carotenoids (10.99 ± 0.030 g BE / 100 g). Conclusion: All of the ethanolic leaves extract of rambutan were very strong antioxidant. Total fenolic content of rambutan leaves extracts had positive and significant correlation with their DPPH scavenging activity and ABTS scavenging activity (p < 0.01). Phenolic compounds in leaves extract of five varietes of rambutan were major contributor in DPPH and ABTS scavenging activities. DPPH scavenging activities of leaves extracts of five varieties of rambutan had linear result with their ABTS scavenging activities.