The effect of ultrasonic energy on the extraction of anthraquinones from senna pericarps

Abstract

Abstract Ultrasonic irradiation increased the extraction rate of rhein glycosides, free anthraquinones and total water-soluble solids from whole senna pericarps, irrespective of the temperature conditions employed. An increase in ultrasonic power from 35 to 100 W increased the yield of extractable constituents over a 15 min period, the ratio of rhein glycosides to total water-soluble solids being higher in extracts prepared using ultrasound than in preparations obtained by simple maceration, but that ratio decreased slightly with an increase in ultrasonic power. Ultrasonic irradiation produced occasional visible damage to epidermal cell walls and the significance of this in the extraction of senna pericarps is discussed.