Phenolic Compound Content, Antioxidant and Radical-Scavenging Properties of Methanolic Extracts from the Seed Coat of Certain Thai Tamarind Cultivars

Methanolic extracts from the seed coats of five Thai tamarind cultivars were analyzed for their phenolic compound content and antioxidant properties. The study found that the Priao-yak extract, with the highest tannin content, exhibited the strongest reducing power, while the Khanti extract, with the highest proanthocyanidin content, showed significant scavenging ability on DPPH and hydroxyl radicals. The Sithong-bao extract, rich in total phenols, proanthocyanidin, and tannins, demonstrated the strongest overall antioxidative activity. These findings suggested that specific phenolic constituents were responsible for the varying antioxidant properties among the different cultivars. The Sithong-bao seed coat extract, in particular, showed potential as a natural antioxidant source for nutraceutical development.