Use of 13C-qNMR Spectroscopy for the Analysis of Non-Psychoactive Cannabinoids in Fibre-Type Cannabis sativa L. (Hemp)

Abstract

Cannabis sativa L. is a dioecious plant belonging to the Cannabaceae family. The discovery of the presence of many biologically-active metabolites (cannabinoids) in fibre-type Cannabis (hemp) has recently given rise to the valorisation of this variety. In this context, the present study was aimed at the multi-component analysis and determination of the main non-psychoactive cannabinoids (cannabidiol, cannabidiolic acid, cannabigerol and cannabigerolic acid) in female inflorescences of different hemp varieties by means of 13C quantitative nuclear magnetic resonance spectroscopy (qNMR). The method proposed here for the first time for the determination of cannabinoids provided reliable results in a competitive time with respect to the more consolidated HPLC technique. In fact, it gave sufficiently precise and sensitive results, with LOQ values lower than 750 μg/mL, which is easily achievable with concentrated extracts, without affecting the quality of 13C-qNMR spectra. In conclusion, this method can be considered as a promising and appropriate tool for the comprehensive chemical analysis of bioactive cannabinoids in hemp and other derived products in order to ensure their quality, efficacy and safety.

Chemical Characterization and Evaluation of the Antibacterial Activity of Essential Oils from Fibre-Type Cannabis sativa L. (Hemp)

“…Scientific research on fibre-type Canabis sativa L. (commonly known as industrial hemp or hemp) has been significantly increasing in recent years [1,2]. The wide pharmacological profile of its non-psychoactive cannabinoids, which belong to the class of terpenophenolics, make them the leading actors of the vast majority of the scientific papers related to this variety [3,4,5,6,7]. Among these compounds, cannabidiol (CBD) represents the most promising one from a pharmaceutical point of view (Figure 1).…”

A Quantitative 1H-NMR Method for Screening Cannabinoids in CBD Oils

“…Prior to the NMR experiments, the samples were dissolved in either pure solvent (CD3OD, CDCl3) or solvent mixtures (CDCl3/CD3OD (3:2, 2:1, v:v) and CDCl3/DMSO-d6 (5:1, v:v)). These solvents and solvent mixtures were previously proposed in the literature for NMR measurement of hemp extracts or edible oils [9,19,20,[22][23][24][25]. To assign the cannabinoid signals in the 1 H NMR spectrum of CBD oils, reference spectra of different cannabinoids were recorded in CDCl3 and their compoundspecific coupling constants, multiplicities, and chemical shift were recorded and verified with literature data.…”

Research Progress of NMR in Natural Product Quantification

“…In addition, 13 C has low sensitivity due to the low isotopic abundance in comparison to 1 H and 13 C signal intensity, which is affected by the nuclear overhauser Enhancement (NOE) effect. Based on this, Marchetti et al [ 103 ] put forward corresponding solutions for reader reference, such as concentrating the samples, measuring the T 1 for each carbon of standard compounds tentatively, and lowering the proton decoupling power to zero. With the continuous improvement of methods, 13 C NMR has been better used for quantitative work on substances.…”

“…Marchetti et al [ 103 ] developed a reliable 13 C qNMR method for the multi-component analysis and determination of the main non-psychoactive cannabinoids (cannabidiol, cannabidiolic acid, cannabigerol, and cannabigerolic acid) in female inflorescences of different hemp varieties. In comparison with the most commonly HPLC technique, this qNMR approach was precise and sufficiently sensitive.…”