DETERMINATION OF ANTIOXIDANT CAPACITY IN PLUCHEA INDICA LESS LEAVES EXTRACT AND ITS FRACTIONS

摘要

Objective: This study was conducted to determine the DPPH free radical scavenging activity of pluchea extract (PE) and its fraction (ethyl acetate (EAF), n-butanol (BF) and aqueous (AF)) and comparing with the its activity of control antioxidant, such as green tea (GE) and rosemary extracts (RE), α-tocopherol succinate (ATS) and BHT. Methods : The antioxidant activity was evaluated by the decrease in absorbance as the result of DPPH˙ color change from purple to yellow at 517 nm by using a stopped-flow spectrometer UV-Vis. AE (antiradical efficiency) was a parameter more exactly used to measure the antioxidant power than EC 50 (efficient concentration to reduce 50% of DPPH concentration). This parameter was determined by EC 50 and TEC 50 (the time needed to reach the steady state). Results: PE and its fraction had free radical-scavenging activity compared with control antioxidant. Based on EC 50 , the orders of ability to scavenging DPPH radicals was determined as the EAF~ GE>PE ~ ATS ~ RE ~ AF>BHT ~ BF. The results were not exactly because BHT and ATS were potentially as a synthetic antioxidant. Therefore AE parameter was used to determine scavenging activity. The classification order of scavenging activity based on AE was BHT>GE ~ ATS>EAF>RE~ BF~ PE~ AF. Conclusion: The PE and its fractions had DPPH free radical scavenging activity. Based on EC 50 and AE parameters, the EAF showed the strongest DPPH free radical scavenging activity compared with PE and the other fractions.