Peculiarities of Use of Bentonite Clay at Solid-Phase Purification of Anthocyanins and Flavonoids from Leaves of Plants

Anthocyanins of red colored leaves of Cercis canadensis L. were found to be 3-glucosides of five common anthocyanidins of delphinidin, cyaniding, petunidin, peonidin and malvidin with overall accumulation more than 350 mg per 100 g of FW in early summer. The content of anthocyanins gradually drops to total disappearance at the late September. Extract of anthocyanins may content a large amount of flavonoids that are not separated during solid phase extraction (SPE) on C18-silica syringe cartridges. In the paper, the ability of bentonite clay as a sorbent for SPE of anthocyanins was investigated. Non-charged flavonoids were shown to compete with anthocyanins during sorption. Meanwhile sorption ability of anthocyanins markedly exceeds that of non-charged flavonoids. The method for anthocyanins and non-charged flavonoids is proposed. Keywords—anthocyanins, Cercis canadensis L., leaves, SPE, flavonoids, clay