Microwave-assisted extraction of cannabinoids and antioxidants from Cannabis sativa aerial parts and process modeling

Abstract

BACKGROUND: Cannabis (Cannabis sativa L.) is one of the most controversial plants. So far, its multiple application in industry for the production of fabrics, paper and construction materials is known. Today, there is increasing interest in its application for medical purposes, as opposed to its opiate activity. In addition to well-known cannabinoids, the presence of polyphenolic compounds and their antioxidant and reductive abilities are of great importance. Therefore the extraction of both constituents, polyphenolics and cannabinoids (Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD)), of industrial hemp was carried out using microwave-assisted extraction (MAE). RESULTS: The effects of different extraction parameters, namely ethanol concentration (30, 50 and 70% v/v), extraction time (10, 20 and 30 min) and solid/liquid ratio (5, 10 and 15 g mL−1), on extraction yield, total phenol content, total flavonoid content, antioxidant activity, reductive capacity, CBD content and THC content were investigated using response surface methodology. For the experimental design, a Box–Behnken design was chosen. In the obtained extracts, the following ranges of targeted compounds were detected: total phenols from 0.8499 to 2.7060 mg gallic acid equivalent mL−1, total flavonoids from 0.4707 to 1.4246 mg catechin equivalent mL−1, THC from 0.0339 to 0.0637 mg mL−1 and CBD from 0.2243 to 1.8415 mg mL−1. Antioxidant activity ranged from 0.0009 to 0.2079 mL mL−1, while reductive capacity ranged from 0.0021 to 0.0066 mL mL−1. CONCLUSION: MAE proved to be a simple, efficient, fast and low environmental impact method for obtaining polyphenols and cannabinoids from C. sativa L. Cannabis herb, which presents a by-product of fiber and cannabis product, showed to be a promising source of bioactive compounds. © 2019 Society of Chemical Industry.