Concentrations of THC, CBD, and CBN in commercial hemp seeds and hempseed oil sold in Korea

Abstract

Hemp seeds and hempseed oil are marketed on- and off-line as health foods and cosmetics and have been reported to have high nutrient contents. However, because of the various side effects of cannabinoids, especially △⁹-tetrahydrocannabinol (THC), many countries regulate upper limits for THC in products, which creates the need for analytical techniques capable of measuring THC, cannabidiol (CBD), and cannabinol (CBN) levels in commercial hemp seeds and hempseed oil. In the present study, hemp seed and hempseed oil extracts obtained by methanol extraction, were analyzed by gas chromatography-mass spectrometry (GC/MS). Validation of the technique used was performed using calibration curves and by determining LODs, LOQs, specificities, selectivities, and intra- and inter-day precision and accuracies. In addition, matrix effects, process efficiencies, recoveries, and sample stabilities were investigated. In hemp seeds, as determined using the fully optimized method THC concentrations ranged from 0.06 to 5.91 μg/g, CBD concentrations from 0.32 to 25.55 μg/g, and CBN concentrations from 0.01 to 1.50 μg/g; CBN/THC ratios ranged from 0.1 to 1.60, and CBD/THC ratios from 0.11 to 62.56. Furthermore, the (THC + CBN)/CBD ratio of most hemp seed samples was less than one. In hempseed oil, THC concentrations ranged from 0.3 to 19.73 μg/mL, CBD concentrations from 6.66 to 63.40 μg/mL, CBN concentrations from 0.11 to 2.31 μg/mL, CBN/THC ratios from 0.12 to 0.42, and CBD/THC ratios from 3.21 to 22.50. Furthermore, (THC + CBN)/CBD ratios in all hempseed oil samples were less than one. The optimized methanol extraction-GC/MS technique was found to be satisfactory for determining THC, CBD, and CBN concentrations in hemp seeds and hempseed oil.

Keywords: Canabinol; Cannabidiol; GC/MS; Hemp seeds; Hempseed oil; Tetrahydrocannabinol.