Optimizations of conditions for maximum recovery of astragalin from Thesium chinense Turcz

Astragalin, one of the flavonoid extracted from plants is increasingly in demand in food and pharmaceutical industries due to its various biological and physiological activities including antioxidation, antiallergy, anti-inflammation and anti-hepatoptoxic. The whole plant of Thesium chinense Turcz is a major source of astragalin. This study developed a low-cost process encompassing the efficient extraction, fractionation, isolation and recrystallization to obtain high-purity astragalin from Thesium chinense and it could improve the economic utilization of this plant. In this study plant was extracted with 80% ethanol for 3 h and extract was fractionated on AB-8 (styrene based copolymer) with water, 20, 40 and 80% aqueous ethanol. Astragalin was isolated by silica gel column and purified by recrystallization with methanol. These conditions resulted 90% recovery of Astragalin with purity.