Quantitative Analysis of Cannabinoids from Cannabis sativa Using 1H-NMR

Abstract

The cannabis plant has been of medicinal interest for centuries. In recent years a lot of research on the medical applications of Cannabis sativa L. has been initiated, as several, mostly European, countries move towards a more liberal view on the use of Cannabis as a medicine. Many different pharmacological properties have been associated with cannabis use, including increased heart rate, drop of body temperature, ataxia and a loss of time-space perception. 1)Amongst the constituents of Cannabis sativa, the cannabinoids have been recognized as the active constituents for most clinical activities. The cannabinoids make up a large family of closely related C 21 compounds and their carboxylic acids and are unique to the cannabis plant.2) Pharmacological activites of the cannabinoids are very diverse, ranging from analgetic and antiemetic to the treatment of glaucoma and multiple sclerosis.3,4) Only four of the 66 known natural cannabinoids 5) are currently commercially available as certified reference standards, i.e.: (Ϫ)-delta-9-tetrahydrocannabinol (D 9 -THC or THC), (Ϫ)-delta-8-tetrahydrocannabinol (D 8 -THC), cannabidiol (CBD) and cannabinol (CBN). There are indications that also these reference compounds have to be re-quantified regularly because of degradation and differences between batches during production. 5)Recently, our laboratory developed a method for the large scale isolation of highly pure cannabinoids from Cannabis sativa flower tops. 7) For the quantitative analysis of these compounds, GC with FID or other detection has been widely used, but this method can not distinguish between cannabinoids and their carboxylic counterparts without prior derivatization.8,9) HPLC with UV detection is more suitable for simultaneous analysis of these compounds, but it proves to be very difficult to separate all components in a single chromatographic run 10,11) and some contaminations cannot be detected because they lack UV absorbance. Furthermore, both methods are sensitive to impurities in the sample, e.g. chlorophyll or lipids, and they usually require a sample clean-up step prior to analysis. Most importantly, the reference compounds needed for the preparation of a calibration curve are not available for many cannabinoids. A review of methods for cannabinoids analysis in biological materials is given by Raharjo. 12)To solve the problems associated with these analytical techniques, the development of a reliable and easy method is required as alternative to the conventional analyses. In this study, we developed an analytical method using 1 H-NMR for cannabinoids without the need for any chromatographic purification. Quantitative NMR has been shown to be very accurate and highly reproducible, within a very short analysis time. The usefulness of quantitative NMR for the validation of natural product reference compounds as well as theoretical aspects have been shown by Maniara and Pauli. 13,14) The developed method was applied on the quantitative analysis of five different isolated cannabinoids. A similar method ha...

Evaluation of the Cyclooxygenase Inhibiting Effects of Six Major Cannabinoids Isolated from Cannabis sativa

“…Scientific samples of cannabinoids (D 9 -THC, THCA-A, CBD, CBDA, CBG and CBGA) were provided by Prof. Robert Verpoorte and Dr. Arno Hazekamp, Leiden University, The Netherlands. The cannabinoids were isolated from Cannabis sativa and characterized and quantified using the chromatography and 1 H-NMR methods as described by Hazekamp et al 23,24) All cannabinoid samples were at least 92% pure.…”

Cannabinoid Receptor 1 Binding Activity and Quantitative Analysis of Cannabis sativa L. Smoke and Vapor

“…-tetrahydrocannabinol (D 8 -THC), CBD, cannabigerol (CBG), cannabichromene (CBC), tetrahydrocannabivarin (THCV), and cannabinol (CBN) were purified and quantified as previously described 22,23) by PRISNA BV (Leiden, The Netherlands). All cannabinoids references were Ͼ98% pure.…”

Chemistry and Biological Activity of Tetrahydrocannabinol and its Derivatives

“…Another possibility structural identification gives the coupling of HPLC with NMR. The interpretation of [ 1 H]-signals that are specific for different substances can also be used for quantification [93].…”