Direct NMR analysis of cannabis water extracts and tinctures and semi-quantitative data on Δ9-THC and Δ9-THC-acid

Abstract

Cannabis sativa L. is the source for a whole series of chemically diverse bioactive compounds that are currently under intensive pharmaceutical investigation. In this work, hot and cold water extracts as well as ethanol/water mixtures (tinctures) of cannabis were compared in order to better understand how these extracts differ in their overall composition. NMR analysis and in vitro cell assays of crude extracts and fractions were performed. Manufacturing procedures to produce natural remedies can strongly affect the final composition of the herbal medicines. Temperature and polarity of the solvents used for the extraction resulted to be two factors that affect the total amount of Δ9-THC in the extracts and its relative quantity with respect to Δ9-THC-acid and other metabolites. Diffusion-edited 1H NMR (1D DOSY) and 1H NMR with suppression of the ethanol and water signals were used. With this method it was possible, without any evaporation or separation step, to distinguish between tinctures from different cannabis cultivars. This approach is proposed as a direct analysis of plant tinctures. © 2007 Elsevier Ltd. All rights reserved.