Optimization of cyclodextrin-assisted green extraction of cannabidiol from industrial hemp leaves: Release behavior, permeability, bioactivity, and stability

Abstract

Cannabidiol (CBD) is an important natural compound of hemp. Cyclodextrin-assisted extraction of CBD from hemp leaves was optimized by single-factor experiments and response surface methodology. The highest extraction yield of CBD was 1.075 ± 0.012 mg/g and the recovery yield was 87.19 % using dimethyl-β-cyclodextrin (DM-βCD), which showed that the extract had a higher proportion of CBD. The optimal conditions were as follows: extraction temperature was 40 ℃, liquid-to-solid ratio was 25.17 mL/g, extraction time was 74.4 min, mass ratio of DM-βCD to hemp leaves was 1.17, and ethanol concentration was 60 %. Different characterizations demonstrated that complexation of DM-βCD promoted CBD extraction and increased the proportion of CBD in the extract. The cumulative release rate of CBD (67.98%) from the extract by DM-βCD-assisted extraction (DAHE) was much higher than that (2.62%) without DM-βCD-assisted extraction (HE). The permeability, bioactivity, and stability of DAHE were also better than that of HE. The better results of DAHE could be due to the inclusion by DM-βCD and the higher proportion of CBD. In conclusion, DM-βCD-assisted extraction was an appropriate method for CBD extraction and the obtained extract with higher CBD proportion and better bioactivity and stability could be applied in many fields.