Residues of herbal hemp leaf teas – How much of the cannabinoids remain?
Herbal teas of fiber-type hemp varieties (Cannabis sativa L.) rich in cannabidiolic acid (CBDA) and cannabidiol (CBD) and poor in Δ9-tetrahydrocannabinol acid (THCA) and Δ9-tetrahydrocannabinol (THC) are very popular today. The conditions for preparing herbal infusions are not well standardized and analysis of the lipophilic cannabinoids in infusions is difficult. Therefore, we analyzed the hemp leaf residues after tea preparation by using a response surface modelling approach to estimate the effects of variations in temperature, water volume and extraction time on the residual content of five cannabinoids (CBDA, CBD, THCA, THC, cannabinol (CBN)) in the hemp leaves after extraction.