ISSN: 0975-8585 January – March 2012 RJPBCS Volume 3 Issue 1 Page No. 12 Research Journal of Pharmaceutical, Biological and Chemical Sciences Antioxidant Activities of Some Thai and Exotic Fruits Cultivated in Thailand. Penpun Wetwitayaklung 1* , Juree Charoenteeraboon 2 , Chutima Limmatvapirat 3 , and Thawatchai Phaechamud 4 1 Dept. of Pharmacognosy, Faculty of Pharmacy, Silpakorn University, Nakhon-Pathom, Thailand 73000 2 Dept. of Biopharmacy, Faculty of Pharmacy, Silpakorn University, Nakhon-Pathom, Thailand 73000 3 Dept. of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon-Pathom, Thailand 73000 4 Dept. of Pharmaceutical Technology, Faculty of Pharmacy, Silpakorn University, Nakhon-Pathom, Thailand 73000 ABSTRACT The twenty-one methanolic extracts of meat or peel of native and exotic fruits cultivated in Thailand were determined their total phenolic content and antioxidant activities by Folin-Ciocalteu reagent and Trolox equivalent antioxidant capacity (TEAC) assay. The ripe fruit of Carissa carandas and the raw fruit of Ficus hirta presented the highest and lowest %yield of extract as 67.20% and 12.86%, respectively. The Terminalia chebula and Baccauea motleyana extracts contained the highest and lowest amount of total phenols, 6.96 and 0.05 g/100g dried fruit, respectively. The T. chebula and Syzygium malaccense extracts contained the highest and lowest amount of total phenols, 16.12 and 0.22 g/100g extract, respectively. The range of TEAC and IC 50 values of the fruit extracts were 0.35–0.003 and 21.33 μg/mL –5.10 mg/mL, respectively. The T. chebula and Diospyros peregrina extracts showed the highest antioxidant activities, while B. motleyana extracts indicated the lowest. The extracts of T. Chebula and D. peregrina (raw fruit) showed equal TEAC value, however the total phenolics content of D. peregrina raw fruit was quite low. Finally almost methanolic extracts of Thai and exotic fruits in this study presented their antioxidant activities in direct proportion to the amount of total phenolics. Keywords: fruits, total phenolics, antioxidant activity, TEAC *Corresponding author Email: penpun@su.ac.th