AKTIVITAS ANTIOKSIDAN BEBERAPA EKSTRAK UMBI LAPIS TIGA MACAM BAWANG DENGAN METODE ABTS DAN DPPH

• Main Author: Permatasari, Listya
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64761
• Institution: Institut Teknologi Bandung

Background and objectives: Antioxidants are compounds that can delay or prevent the oxidation of lipids or other molecules by inhibiting the initiation or propagation of oxidative chain reactions. Most of herbs have antioxidant properties which are active compounds such as flavonoid and phenolic compounds. The aim of this research are to study antioxidant activity from various bulbs extracts of three kinds of Allium and correlations between total phenolics, flavonoids and carotenoids contents and ABTS, DPPH scavenging activities. Method: Ectraction was done by reflux using gradient polarity solvent (n-hexane, ethyl acetate, ethanol). The extracts were vaporated using rotavapor. Chromatogram pattern on each extract of samples were observed by thin layer chromatography (TLC). Then, qualitative antioxidant activity for each extracts were monitored by TLC using ABTS 0.2% in ethanol and DPPH 0,2% in methanol, quantitative antioxidant activity for each extract using ABTS and DPPH assays and determination of total phenolics, flavonoids and carotenoids were also measured for each extracts. Results: Antioxidant activity (%) of n-hexane extracts, onion were 12,47 — 4,94; 16.8 6.1, garlic were 17,43 + 4.86; 7,13 4.05 and red onion were 13.26 +- 4.73; 9.4 4.23 % as determined using ABTS and DPPH assays, respectively. Antioxidant activity (%) of ethyl acetate extracts, onion were 49.03 4.37; 45.86 = 3.38, garlic were 23.69 -= 4.93; 10.73 = 1.2 and red onion were 36.25 -'-- 4.44; 40.22 = 3.06. Antioxidant capacities (%) of ethanol extracts, onion were 21.01 7_ 4.93; 8.23 = 3.1, garlic were 18.68 -= 4.93; 7.68 = 2.66 and red onion were 20.25 -4- 4.6; 10.67 = 2.68 %. ABTS and DPPH scavenging activities of red onion bulbs extracts had positively high correlation with total phenolics (ARTS r = 0.917; DPPH r = 0.987) and total flavonoids (ABTS r = 0.914; DPPH r = 0.99) but had negative correlation with total carotenoids (ABTS r = 0.431; DPPH r = 0.214). Conclusion: The highest antioxidant activity of various bulbs extracts from three kinds Allium was given by ethyl acetate extract of onion (P2) with ABTS scavenging activitiy 49.03% and DPPH scavenging capacity 45.86%. While the lowest antioxidant activity of various bulbs extracts was demonstrated by n-hexane extract of garlic (Q1), with DPPH scavenging capacity 7.13% and n-hexane extract of onion (P1) with ABTS scavenging activity 12,47%. Antioxidant activity in onion and red onion bulb extracts can be estimated indirectly by using total phenolics and flavonoids since they showed highly positive correlation with ABTS and DPPH assays. Total phenolics and flavonoids were the major contributors in antioxidant activities in onion and red onion bulbs.