Cannabis sativa (Hemp) Seeds, Δ(9)-Tetrahydrocannabinol, and Potential Overdose

Introduction: Cannabis sativa (hemp) seeds are popular for their high nutrient content, and strict regulations are in place to limit the amount of potentially harmful phytocannabinoids, especially Δ(9)-tetrahydrocannabinol (Δ(9)-THC). In Canada, this limit is 10 μg of Δ(9)-THC per gram of hemp seeds (10 ppm), and other jurisdictions in the world follow similar guidelines. Materials and Methods: We investigated three different brands of consumer-grade hemp seeds using four different procedures to extract phytocannabinoids, and quantified total Δ(9)-THC and cannabidiol (CBD). Discussion: We discovered that Δ(9)-THC concentrations in these hemp seeds could be as high as 1250% of the legal limit, and the amount of phytocannabinoids depended on the extraction procedure employed, Soxhlet extraction being the most efficient across all three brands of seeds. Δ(9)-THC and CBD exhibited significant variations in their estimated concentrations even from the same brand, reflecting the inhomogeneous nature of seeds and variability due to the extraction method, but almost in all cases, Δ(9)-THC concentrations were higher than the legal limit. These quantities of total Δ(9)-THC may reach as high as 3.8 mg per gram of hemp seeds, if one were consuming a 30-g daily recommended amount of hemp seeds, and is a cause for concern for potential toxicity. It is not clear if these high quantities of Δ(9)-THC are due to contamination of the seeds, or any other reason. Conclusion: Careful consideration of the extraction method is very important for the measurement of cannabinoids in hemp seeds.