Quantitative analysis of cannabinoids in cannabis sub-species and plant parts using validated HPLC and optimization of decarboxylation for enhanced CBD yield

Cannabis is a significant plant widely utilized in various sectors due to its rich content of secondary metabolites, including cannabinoids, terpenes, and phenolic compounds. Among these, cannabinoids are the most studied active molecules. This study presents the validation of a high-performance liquid chromatography (HPLC) method for the quantitative analysis of key cannabinoids. The validated method was applied to determine the cannabinoid profile in different sub-species (Cannabis sativa (C. sativa), Cannabis indica (C. indica), and Cannabis ruderalis (C. ruderalis)) and parts (upper, middle, and lower) of the Cannabis sativa L. plant. Additionally, the decarboxylation parameters (temperature and time) for the upper plant parts were optimized using response surface methodology to maximize CBD yield, a cannabinoid widely used for medicinal purposes. The validation results demonstrated that all cannabinoids were determined with excellent linearity (r2 between 0.93 and 0.99) over a concentration range of 0.110-250 mg/L, with detection limits between 0.030 and 0.36 mg/L, and relative standard deviations (%RSD) below 5.50 %. The analysis showed that CBD was the predominant cannabinoid in C. sativa, while Delta 9-THC was the primary cannabinoid in C. indica. Furthermore, the highest concentrations of active cannabinoids were found in the upper parts of the plants. Optimal decarboxylation conditions were determined to be 142.5 degrees C and 59.25 min. These findings provide a valuable method for cannabinoid quantification in cannabis plants and offer insights for maximizing CBD yield, benefiting both academic research and industrial applications.