Microwave-assisted extraction of phytochemicals from Cannabis sativa L. inflorescences with 2-methyloxolane

Abstract

2-methyltetrahydrofuran, also known as 2-methyloxolane (2-MeOx), was investigated for the extraction of phytochemicals from Cannabis sativa L. inflorescences. Dynamic maceration with 2-MeOx yielded comparable CBD (75.45 mg CBD/g DM) to ethanol (77.71 mg) and hexane (75.09 mg). The use of water-saturated 2-MeOx (4.5% water) increased the CBD recovery to 81.30 mg/g DM and the polyphenols content. 2-MeOx was also a good solvent for the recovery of hemp terpenes (87906−120485 mg/kg extract). Microwave-assisted extraction improved the CBD yield and shortened the time (by 3–30 times). Optimised microwave conditions resulted in higher CBD yields (84.18−86.76 mg CBD/g DM) compared to conventional extraction. Microwave-assisted decarboxylation-extraction with 2-MeOx was less effective than ethanol for CBDA decarboxylation (about 3–10 times lower). Finally, a single-mode microwave reactor for flow extraction was tested, achieving 75.48 mg CBD/g DM with 2-MeOx (3.65% water) at 60 °C in 10 min. Further optimisation is required for continuous microwave extraction with 2-MeOx.