In this study, water and various concentrations of ethanol in water (30%, 50%, 70%, and 90%) were used as a solvent in the extraction of two different samples of hemp (Cannabis sativa L.). The extraction yield, total phenols content, total flavonoids content, antioxidant activity, and reductive capacity were determined in the obtained extracts. The extraction yield was from 8.16 to 19.56%, the content of total phenols was in the range from 5.85 to 17.05 mg GAE/g dw, and content of total flavonoids was in the range from 5.85 to 9.25 mg CE/g dw. Antioxidant activity was tested by DPPH assay and EC 50 values were from 0.1331 to 0.7563 mg/mL, while EC 50 values obtained by reducing power test ranged from 0.4450 to 1.1980 mg/mL. Ethanol/water mixture (50%) was determined to be the best solvent for the extraction of phenolic compounds from both hemp samples. Total phenols content in 50% ethanolic extracts were 17.05 mg/g dw and 9.25 mg/g dw for young and mature hemp, respectively.

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 ( 9 -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. RESULTS AND DISCUSSION Model fittingAccording to the literature, C. sativa has been mostly extracted by conventional extraction methods by application of different J Chem Technol Biotechnol 2020; 95: 831-839

Currently, there are increased interests in growing grain and fiber hemp (Cannabis sativa L.) as well as in large-scale hemp products. Cannabis has been grown/utilized for thousands of years as a fiber, grain, and drug/medicinal plant. However, the strict control of cannabis cultivation to combat illegal use, the spread of new yarns and oilseeds, and the advent of cheap synthetic fibers caused a decreased/eliminated hemp production. Hemp has been banned in most of the world for more than seven decades; it missed out on the Green Revolution and the adoption of new technologies and varieties, creating a knowledge gap. After the 2014 and 2018 Farm Bill in the USA, hemp became legal and the land grand universities launched research programs. The ability to utilize the entire plant for multiple purposes creates opportunity for the market to value hemp products. Hemp production technology varies depending on the type of hemp cultivated (grain, fiber, or cannabinoids), soil characteristics, and environmental factors. Hemp has the potential to be a very sustainable and ecologically benign crop. Hemp roots have a significant potential for absorbing and storing heavy metals such as lead, nickel, cadmium, and other harmful substances. In addition, hemp has been proven to be an excellent carbon trap and biofuel crop. Hemp has the ability to successfully suppress weeds, and it is generally regarded a pesticide-free crop. The purpose of this paper is to examine historic and recent industrial hemp (grain and fiber) literature, with a focus on hemp agronomy and utilization.

Hemp (Cannabis sativa L.) was one of the earliest domesticated plant species. Biological classification (taxonomy or systematization) manifests evolutional relationships between taxons according to trait similarities. When it comes to taxonomy, hemp is one of the most controversial plant species due to significant effects of environmental conditions on hemp phenology and expression of quantitative traits as well as different levels of gender expression observed in hemp plants. Controversial taxonomy of hemp has gone through several phases throughout history. The attitude on the number of species within the genus Cannabis and the criteria used in taxonomic units division were under dispute. Initially focused on morphological characteristics and geographical origin, the approach was greatly amended by the development of molecular and biochemical techniques. The main cause of taxonomic uncertainties is the inbreeding ability of all wild Cannabis populations, resulting in continual variability of quantitative traits. The aim of the paper is to review the history of Cannabis classification including different approaches to this scientific issue.

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