Extraction optimisation of bioactive compounds from Hemp upper part material (Cannabis sativa L.)

Abstract

Cannabis (Cannabis sativa L.) has been a well-known plant since early times, rich in active compounds such as phenols, flavonoids and cannabinoids. The concentration of these active compounds various widely depending on extraction method, plant material, and solvents used. This study aims to optimise the extraction of bioactive compounds from the top 30 cm section of Cannabis sativa L, grown at the Agricultural Experimental Station in Swojec, Poland (coordinates 51°07'05.4"N 17°08'37.9"E). One gram of dry plant material was extracedusing three types of solvents (ethanol, methanol and propanol), three solvent volumes (5, 10 and 15 ml) and three shaking times (20, 40 and 60 min) according to a central composite design using response surface methodology. Extractants were analysed for yield, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, total phenolic content and ferric reducing antioxidant power (FRAP). Process optimisation and interaction effects were analysed using Statistica software 14.1.0.4 (p<0.05). The type of solvent and its volume significantly affected the extraction yield and bioactivity of the compounds. The maximum extraction yield (4.17±0.95%) and DPPH activity (23.48±1.60 Trolox Eq mg/g dry plant) were obtained with 15 ml of propanol and 60 min of shaking. Meanwhile, the highest FRAP (161.10±11.40 Trolox Eq mg/g dry plant) and total phenolic content (1128 Galic acid Eq µg/g plant) were achieved with 15 ml methanol and 60 min shaking. The optimisation results also showed that 15 ml of ethanol with 20 min, 15 ml methanol with 58.38 min and 15 ml of propanol with 60 min are the optimal conditions for each solvent respectively. The study highlights the importance of selecting appropriate extraction methods to fully exploit Cannabis sativa as a source of functional food ingredients.