ANTIOXIDATIVE COMPONENTS ISOLATED FROM THE SEED OF TAMARIND (TAMARINDUS-INDICA L)

Antioxidative activity of tamarind (Tamarindus indica L.) seeds was investigated. An ethanol extract prepared from the seed coat exhibited antioxidative activity as measured by the thiocyanate and thiobarbituric,acid (TEA) method, but there was no activity in the extract prepared from germ. The ethyl acetate extract prepared from seed coat had strong antioxidative activity. To determine antioxidative compounds in the seed coat chemically, preparative HPLC was carried out, then 2-hydroxy-3',4'-dihydroxyacetophenone (TAO), methyl 3,4-dihydroxybenzoate (TA1), 3,4-dihydroxyphenyl acetate (TA2), and (-)-epicatechin (TA3) were isolated from the ethyl acetate extract and identified. TAO, TA1, and TA2 had-strong antioxidative activity in the linoleic acid autoxidation system as measured by the thiocyanate and TEA method as well as alpha-tocopherol. These results suggest that tamarind seed coat, a byproduct of tamarind gum industries, can be used-as a safe and low-cost source of antioxidants.