Antiradical Activities of Rambutan Peel: Study from Two Cultivars

摘要

Background: Rambutan is tropical fruit consumed either in fresh or processed fruit. The direct consumption or processing of rambutan fruit resulted in high amount of waste from peel and seed, therefore, it is necessary to take benefit from rambutan peel to be used as food supplement via antioxidant properties. Objective: This study is intended to evaluate the antiradical activities of m ethanolic extract and its fraction of rambutan peel from two cultivars (Aceh and Binjai) and to correlate the antiradical activities with phenolics and flavonoid contents. Methodology: The rambutan peel from two cultivar (Aceh and Binjai) is dried, macerated with methanol, evaporated and added with water. The m ethanolic extract is fractionated with petroleum ether, chloroform and ethyl acetate to get the corresponding fraction. M ethanolic extract and its fraction are then subjected to antiradical activity measurement using synthetic DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical, phenolics determination and flavonoid determination. Results: The m ethanolic extract and its fraction,either cultivar Aceh or Binjai,revealed the high antiradical activities with similar. Ethyl acetate fraction exhibited the strongest antiradical activities among samples evaluated with IC₅₀ values of 2.66 μg mL^?1 (cultivar Aceh) and 2.62 μg mL^?1 (cultivar Binjai). Ethyl acetate fraction also exhibited the strongest phenolics and flavonoid contents accounting of 37.72±4.52 g Gallic Acid Equivalent (GAE)/100 (Aceh) and 32.40±2.37 g GAE/100 g (Binjai). The correlation between antiradical activities with phenolics and flavonoids contents showed with correlation, each with R² value of 0.0271 (phenolics) and 0.1122 (flavonoids). Conclusion: The m ethanolic extract and its fraction of rambutan peel cultivar Aceh and Binjai revealed strong DPPH antiradical activities therefore, rambutan peel can be exploited as natural antioxidant sources and is potential to be used as functional food.