ANTIOXIDANT ACTIVITY OF TUBERS FROM FOUR VARIETIES OF SWEET POTATO [IPOMOEA BATATAS (L.) LAMK.] USING DPPH AND FRAP METHODS

• Main Author: Suhendy, Hendy
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46548
• Institution: Institut Teknologi Bandung

Background and purposes: Life style of society, especially in selecting food and increasing in pollutants, trigger the formation of radicals which potentially causing various diseases such as cancer. The weakness of synthetic antioxidant in side effect will be the strength of natural antioxidant. One of natural antioxidant source is sweet potato which contain high flavonoid. The objectives of this study were to determine the antioxidant activity of tubers from four varieties of sweet potato by determining IC50 of DPPH and EC50 of FRAP, determine total phenolic and flavonoid, analyze the correlation of total phenolic and flavonoid with DPPH IC50 and FRAP EC50 and correlation between DPPH IC50 and FRAP EC50. Methods: Extraction was carried out by reflux using three solvents with increasing polarity, namely n- hexane, ethyl acetate and ethanol. The extract was monitored using thin layer chromatography (TLC). Determination of IC50 DPPH and EC50 FRAP capacity, total phenolic, flavonoid and carotenoid content were done by UV - visible spectrophotometry. Correlation of total phenolic, flavonoid, with IC50 DPPH and EC50 FRAP, and correlation between IC50 DPPH and EC50 FRAP were analyzed by Pearson’s method. Results: IC50 DPPH of ethyl acetate and ethanolic extracts varied from 10.54 ?g/mL to 98.18 ?g/mL. Ethyl acetate extract of purple-orange tubers gave the highest phenolic content (11.91 g GAE/100 g) and flavonoid content (17.83 g QE/100 g). Total phenolic in purplepurple tubers extract had significantly negative correlation with its IC50 DPPH, while total phenolic and flavonoid content of purple-orange tubers extract showed negative and significant correlation with their IC50 DPPH dan EC50 FRAP. Conclusion: Ethyl acetate and ethanolic tubers extracts of four varieties of sweet potato had strong antioxidant activity to very strong antioxidant activity. Phenolic compounds in purple-purple tubers were the main contributor in its antioxidant activity using DPPH method, while phenolic and flavonoid compounds were the main contributor in antioxidant activity of purple-orange tubers by DPPH and FRAP methods. DPPH and FRAP methods gave linear antioxidant activity in purple-purple and purple-orange tubers of sweet potato.