Water-ethanol extraction of hydroxycinnamonic acid from brown knapweed

Abstract

Five hydroxycinnamonic acids were found and the presence of chlorogenic and caffeic acids was confirmed. The dominating compound is caffeic acid. The following optimal conditions of water-ethanol extraction of the total hydroxycinnamonic acids from brown knapweed are experimentally selected: volume ethanol fraction – 80%; extraction time – 6 hours; extraction temperature – 80oС; extraction multiplicity- three times; the ratio of brown knapweed and 80% ethanol – 1:50; the degree of brown knapweed grinding – 500 μM (microns). The nature of the extraction of the total hydroxycinnamonic acids is determined by the dominating compound – caffeic acid. Total content of hydroxycinnamonic acids in brown knapweed taking into account the selected optimal extraction conditions makes, on the average, 2.6%. Volume ethanol fraction; time, temperature and multiplicity of extraction statistically significantly affect the concentration of hydroxycinnamonic acids in the extractions obtained. The most critical factor of water-ethanol extraction is extraction time.