Monitoring metabolites production and cannabinoids analysis in medicinal Cannabis trichomes during flowering period by 1H NMR-based metabolomics
Cannabis trichomes are known as the main site of cannabinoids production, the responsible compounds for most biological activities of the plant. This study reports 1H NMR based-metabolomics and cannabinoids analysis of trichomes of 4 medicinal Cannabis varieties, Bediol, Bedica, Bedrobinol, and Bedrocan, in order to investigate cannabinoids production and metabolites profiles of the trichomes during the last 4 weeks of flowering period. Analysis of 1H NMR spectra revealed totally 6 identified cannabinoids in the chloroform extracts, THCA (1), CBDA (2), CBCA (3), CBGA (4), THC (5) and CBD (6), and 20 compounds in the water extracts including sugars, amino acids, and other acidic compounds. Quantification analysis using 1H NMR method showed that production of total cannabinoids of Bedrocan and Bedica trichomes increased from week 5 (Bedrocan: 63.01 mg/g) till week 7 (Bedrocan: 111.04 mg/g) and then decreased at week 8 (Bedrocan: 79.76 mg/g). Meanwhile cannabinoids production of Bedrobinol and Bediol trichomes increased during the monitoring time. Different metabolites profiles within trichomes varieties were revealed by PLSDA models of metabolomics. Important differential metabolites in this discrimination were THCA (1) and CBDA (2) on the chloroform extracts, and were asparagine, choline, fructose and glucose on the water extracts. Furthermore PLSDA classified the trichomes of every variety based on their harvested weeks. THCA (1) was found as an important discriminant compound in the chloroform extracts of every variety. Meanwhile, threonine, asparagine and fructose were detected as differential metabolites in the water extracts of every variety. This study indicated that Cannabis tricomes during flowering period produced metabolites, particularly cannabinoids in different amounts depending on the time and the plant variety. Furthermore it is the first report for monitoring metabolites production in plant trichomes using 1H NMR-based metabolomics.