The differentiation of fibre- and drug type Cannabis seedlings by gas chromatography/mass spectrometry and chemometric tools

Institut de Police Scientifique, School of Criminal Sciences, Batochime, University of Lausanne, 1015 Lausanne-Dorigny, Switzerland.
Forensic science international (Impact Factor: 2.14). 04/2010; 200(1-3):87-92. DOI: 10.1016/j.forsciint.2010.03.034
Source: PubMed


Cannabis cultivation in order to produce drugs is forbidden in Switzerland. Thus, law enforcement authorities regularly ask forensic laboratories to determinate cannabis plant's chemotype from seized material in order to ascertain that the plantation is legal or not. As required by the EU official analysis protocol the THC rate of cannabis is measured from the flowers at maturity. When laboratories are confronted to seedlings, they have to lead the plant to maturity, meaning a time consuming and costly procedure. This study investigated the discrimination of fibre type from drug type Cannabis seedlings by analysing the compounds found in their leaves and using chemometrics tools. 11 legal varieties allowed by the Swiss Federal Office for Agriculture and 13 illegal ones were greenhouse grown and analysed using a gas chromatograph interfaced with a mass spectrometer. Compounds that show high discrimination capabilities in the seedlings have been identified and a support vector machines (SVMs) analysis was used to classify the cannabis samples. The overall set of samples shows a classification rate above 99% with false positive rates less than 2%. This model allows then discrimination between fibre and drug type Cannabis at an early stage of growth. Therefore it is not necessary to wait plants' maturity to quantify their amount of THC in order to determine their chemotype. This procedure could be used for the control of legal (fibre type) and illegal (drug type) Cannabis production.

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    • "The data that have been used to perform the present work come from previous studies focused on the discrimination of cannabis seedlings using their chemical profiles and chemometric tools. The implemented methodology is described in detail in [1,2]; a GC–MS analysis was used to establish the chemical profile for every cannabis seedling. Fifteen target compounds were selected taking into account their presence in drug type (illegal) and fiber type (legal) Cannabis. "
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    ABSTRACT: This study presents a classification criteria for two-class Cannabis seedlings. As the cultivation of drug type cannabis is forbidden in Switzerland, law enforcement authorities regularly ask laboratories to determine cannabis plant's chemotype from seized material in order to ascertain that the plantation is legal or not. In this study, the classification analysis is based on data obtained from the relative proportion of three major leaf compounds measured by gas-chromatography interfaced with mass spectrometry (GC-MS). The aim is to discriminate between drug type (illegal) and fiber type (legal) cannabis at an early stage of the growth. A Bayesian procedure is proposed: a Bayes factor is computed and classification is performed on the basis of the decision maker specifications (i.e. prior probability distributions on cannabis type and consequences of classification measured by losses). Classification rates are computed with two statistical models and results are compared. Sensitivity analysis is then performed to analyze the robustness of classification criteria.
    No preview · Article · Sep 2014 · Forensic Science International
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    • "Detection was by Odyssey Ò Imaging system (Li-COR Biosciences, Lincoln, NE, USA). pCB 'mix' was a set ratio of 5.2 consisting of 1 lM THC/100 nM CBN/300nM CBD (Broseus et al. 2010). "
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    ABSTRACT: Cannabinoids affect immune responses in ways that may be beneficial for autoimmune diseases. We sought to determine whether chronic Cannabis use differentially modulates a select number of immune parameters in healthy controls and individuals with multiple sclerosis (MS cases). Subjects were enrolled and consented to a single blood draw, matched for age and BMI. We measured monocyte migration isolated from each subject, as well as plasma levels of endocannabinoids and cytokines. Cases met definition of MS by international diagnostic criteria. Monocyte cell migration measured in control subjects and individuals with MS was similarly inhibited by a set ratio of phytocannabinoids. The plasma levels of CCL2 and IL17 were reduced in non-naïve cannabis users irrespective of the cohorts. We detected a significant increase in the endocannabinoid arachidonoylethanolamine (AEA) in serum from individuals with MS compared to control subjects, and no significant difference in levels of other endocannabinoids and signaling lipids irrespective of Cannabis use. Chronic Cannabis use may affect the immune response to similar extent in individuals with MS and control subjects through the ability of phytocannabinoids to reduce both monocyte migration and cytokine levels in serum. From a panel of signaling lipids, only the levels of AEA are increased in individuals with MS, irrespective of Cannabis use or not. Our results suggest that both MS cases and controls respond similarly to chronic Cannabis use with respect to the immune parameters measured in this study.
    Full-text · Article · Aug 2014 · Inflammopharmacology
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    • "Hemp varieties used for drug consumption, characterized by a high content of D-9-tetrahydrocan- nabinol (THC), are often not distinguishable morphologically from fiber varieties with a lower content of THC. C. sativa subspecies are divided into several chemical phenotypes. The relative proportions of THC, CBN (cannabinol) and CBD have been used by various authors for distinguishing three predominant chemotypes: I (drug type, the predominant cannabinoid is THC) II (intermediate type, the predominant cannabinoids are THC and CBD) and III (fibre type, the predominant cannabinoid is CBD) (Broseus et al. 2010). The D-1-tetrahydrocannabinolic acid synthase is considered to be a key enzyme controlling the psychoactivity (i.e. level of THC) of Cannabis because this enzyme mediates the biosynthetic step of THC (Shoyama et al. 2012). "
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    ABSTRACT: Accessions of wild and domesticated hemp (Cannabis sativa L.) originating from Colombia, Mexico, California, Bolivia, Thailand, Afghanistan, Serbia, Hungary, south Africa and different regions of China, were studied by means of DNA polymorphisms in order to discriminate between drug and fiber types. Analysis of molecular variance (AMOVA) was used to partition the total genetic variance within and among populations. The significance of the variance components was tested by calculating their probabilities based on 999 random permutations. AMOVA revealed 74 % variation among accessions and 26 % within accessions, all AMOVA variation was highly significant (P < 0.001). The cluster analysis of molecular data, grouped accessions into eight clusters and gave a matrix correlation value of r = 0.943, indicating a very good fit between the similarity values implied by the phenogram and those of the original similarity matrix. In this study, DNA polymorphisms could discriminate the fiber and drug types, and accessions were grouped in accordance to their classification and uses. In addition, seed size variation and micromorphological characters of seeds were studied by means of a scanning electron microscope (SEM). Seeds varied significantly in size, and were bigger in the fiber types. SEM analysis exhibited variation of micromorphological characters of seeds that could be important for discriminating the fiber or drug types.
    Full-text · Article · Dec 2013 · Genetic Resources and Crop Evolution
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