Antioxidative Potentials of Some Thai Indigenous Vegetables and Fruits

Eleven Thai indigenous vegetables and fruits, commonly consumed in the Northeast region of Thailand were purchased at a local market, Surnin Province, Thailand. Edible parts such as buds (young leaves and shoots), leaves roots, fruits or flowers were used for analysis. Total phenolic contens were determined using Folin-Ciocalteu method and the antioxidant activity was assessed the free radical scavenging using two methods; ABTS and DPPH assays. THe activity was expressed as Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2 - carboxylic acid) equivalent antioxidant capacity (TEAC) and the amount of plant materials necessary to decrease DPPH (2,2 - Diphenyl -1- picrylhydrazyl) radical concentrate by 50% (EC₅₀) respectivey. Thai indigenous plants studied are a tich source of antioxidants, The phenolic contents ranged from 42.6 to 3434.6 mg GAE/g dry matter (DM) or 379.1 to 55985.4 mg GAE/100g fresh weight (FW) of plant materials. THe high leel contents (>200 mg GAE/g DM) consisted of buds of Careya sphaerica, Cratoxylum formosum, Syzygium gratum, Azadirachta indica Juss var Siamensis and fruit of Phyllanthus embilca. The moderate level (100-500 mg GAE/g DM) was found in the Musa sapientum flower, Acacia pennat buds, Eugenia cumini and Lepisanthes rubiginosa fruits. The low level (