Extraction of nettle leaves using synthetic esters of fatty acids

Abstract

The extractive power of synthetic esters of higher fatty acids, widely used as emollients in cosmetics, has been studied. Three popular emollients — isopropyl myristate (IPM), capryl-caprinic triglycerides (CCT) and soybean oil (SO) — were used to isolate biologically active substances from nettle leaves (Folia urtica). The qualitative compositions of lipophilic biologically active compounds in all extracts have proved to be identical, including chlorophyll derivatives, carotenoids, and some unidentified substances. The extractive power of emollients with respect to chlorophyll derivatives increases in the following order: SO < CCT < IPM. The process of two-phase extraction of nettle leaves using natural emollients and synthetic esters of fatty acids as the nonpolar phase has been studied. The nature of the polar phase involved in the two-phase extractant (TPE) has been found to strongly influence the amount of chlorophyll derivatives extracted from the plant material. The maximum concentration of chlorophyll derivatives in the nonpolar phase (soybean oil and synthetic emollients) was obtained using a water-ethanol mixture as the polar phase. It is established that the use of TPEs also enriches the qualitative composition of extracts. The best results in case of the IPM-60% ethanol TPE system were obtained using preliminary maceration of a raw plant material with the nonpolar (IPM) phase. In the case of the soybean oil-60% ethanol TPE system, the best results were obtained upon maceration with the polar (aqueous ethanol) phase.