Extraktion labiler Naturstoffe mit überkritischen Gasen¹

Abstract

The extraction of valepotriates from Valeriana wallichii roots with supercritical gases and solvents is described. Di-drovaltrate and valtrate are obtained in amounts of 80 to 90 per cent and undecomposed with supercritical carbon dioxide and trifluoromethane. The diffusion of the valepotriates in the drug particles requires longer times for exhausting extraction, as maceration tests proved. The supercritical extraction media yield extracts with 60 to 70 per cent total valepotriates compared with extracts obtained with petroleum ether or dichloromethane (50 per cent). The trifluoromethane extracts can be compared in yield and composition to those obtained with carbon dioxide, yet trifluoromethane is advantageous in regard to the better solubility of the valepotriates at a relatively low pressure (70 to 80 bar) and at 30 to 40° C.

Key Word Index

Valeriana wallichii - Valepotriates - Extraction - Supercritical Gases - Carbon Dioxide - Trifluoromethane.