Cannabidiol extraction from industrial hemp

This article details the findings where cannabidiol was extracted out of industrial hemp. The full study is available online. For more information on Memmert Universal Oven U, check out the flyer and product page. Detailed information can be found via inquiry in our contact form or email a Memmert expert.

Universal oven U is capable of precision extraction in the overall cannabis extraction and processing system. Further, decarboxylation in oven is another aspect of its application.

This is an image of commercial hemp extract.

Hemp extract for commercial use.

What is Cannabidiol (CBD)?

CBD is known as the main cannabinoid components derived from hemp, also known as Cannabis sativa L. CBD possesses no psychotropic effects as opposed to Δ9 -tetrahydrocannabinol (THC).

Benefits of CBD

Why not? The reason is that cannabidiol does not activate the CB1 and CB2 cannabinoid receptors of the brain. CBD is known for several properties and effects:

Hemp, CBD and THC

CBD can be found in hemp across its many species and varieties available. THC content is low in industrial hemp compared to CBD. These two are run by separate genes. It is believed that CBD content can be influenced by selecting chemocultivar type (type I low CBD content, type II and III high CBD content).

A rich source of CBD would be fiber hemp (C. sativa). This hemp is primarily used for fiber production and consists of 95% proportion of total cannabinoids in it. However, sometimes these serve other uses. When hemp has low THC, high CBD/phenolic compounds, the applications change from fiber, seed, energy to medicinal use.

Methods for CBD determination in hemp are gas and liquid chromatography. This study looks into CBD and CBGA content determination.

The aim of this study was to determine the CBD, cannabidiolic (CBDA), and canabigerolic acids (CBGA), content in parts of industrial hemp that are possible waste material in the production of hemp fiber, and could be used for CBD extraction.

Materials and methods

Field experiment

Hemp (Cannabis sativa L.) are chosen: 'Finola' (dioecious)and 'Bialobrzeskie' (monoecious). These are grown in plots and pass the 0.2% THC limit set by the EU. The researchers shared the meteorological data of the growing phase.

A table detailing time period across months with temperature and precipitation during a cannabis experiment with hemp.

Meteorological data during the growing period in 2012 and 2014. Courtesy of Journal of Central European Agriculture.

Half of one plot area, 6 m², is aimed at full-flowering stage of the hemp while the other half is sampled at ripening stage. Samples are divided into leaves, roots, stems, and inflorescences/seeds. Dry content of the biomass is determined by way of oven drying at 135 °C for 2 hours.

Learn more about heating and drying ovens here. There is a selection of vacuum oven, universal oven, cleanroom drying oven, paraffin oven and more.

Sample preparation for HPLC analysis

Samples are taken from 30 plants per plot for the purposes of HPLC analysis. Read about what is HPLC analysis here.

The plants are taken randomly during flowering stage. Heights of entire plants are measure and samples are divided into inflorescences, stems, leaves and roots. The researchers cut individual parts of the plants into 1 cm lengths, mixed it and the representative sample, weighing in at 150g, was frozen and lyophilised (-50 °C).

Seeds are sampled at full maturity stage. Seed materials are frozen and lyophilised (-50 °C), and dried matter is stored in a freezer at -18 °C. Later, lyophilised material is grounded and a portion of it is extracted with 3 ml of ethylacetate by using a water bath for 30 minutes at 40 °C.

For information on laboratory water baths, their uses, benefits, features and more, read here.

Post-centrifugation (using 1800g for a 10-minute period), sediment goes through suspension twice, supernatants are pooled, ethylacetate evaporation occurs, and residue is dissolved in methanol.

Decarboxylation using Memmert universal oven U

At this point, the researchers move forward to the next stage. Here, heating of the hemp extracts mentioned earlier require specialized laboratory equipment known for precision, control, and reliability.

During decarboxylation, the hemp extracts are place into a universal oven, UF260, which is a drying oven, set to decarboxylation oven temperature of 50 °C for 180 min, and then later set to 145 °C for 15 min.

Some highlights of the device are:

Temperature range up to +300 °C
9 model sizes (32 to 1060 litres volume)
2 model variants: SingleDISPLAY and TwinDISPLAY
Natural convection or forced air circulation N/F

This is a Universal Oven from Memmert that can be used for various applications including those with cannabis.

Universal oven UF260plus from Memmert is ideal for the cannabis extraction system.

This is an infographic explaining the advantages of using a Memmert Universal oven for the cannabis extraction

Advantages of the Memmert universal oven.

HPLC analysis

After using the universal oven extraction equipment, HPLC analysis follows next for the study. Here, CBD, cannabidiolic acid (CBDA), and cannabigerolic acid (CBGA) values are determined by their retention times. CBD, CBGA, and CBDA content was derived from the calibration curve at 220 nm. Furthermore, the researchers recorded that the limit of detection (LOD) was 0.013 μg/ml and limit of quantification (LOQ) was 0.044 μg/ml. Afterwards, LC-MS analysis was carried out.

Results

This table shows us different samples of hemp and their canabidiol levels.

The mean canabidiol level in C. sativa in mg/kg DM (mean ± standard deviation) in 2012. Courtesy of Journal of Central European Agriculture.

This is an image of a table that visualizes production of dry matter and potential CBD production of hemp.

Production of dry matter and potential CBD production of two varieties of hemp (mean ± standard deviation). Courtesy of Journal of Central European Agriculture.

This is a graph showing CBD content in a plant.

Interannual differences in the CBD level in different hemp parts of Bialobrzeskie variety (mean ± standard deviation). Different small letters (a - b) represent statistically significant differences (P <0.05) between the years in the plant part. Courtesy of Journal of Central European Agriculture.

This table shows the mean value of CBDA.

The mean CBDA level in C. sativa in mg/kg DM (mean ± standard deviation) in 2012. Courtesy of Journal of Central European Agriculture.

The mean CBGA level in C. sativa in mg/kg DM (mean ± standard deviation) in 2012. Courtesy of Journal of Central European Agriculture.

This table shows us the change of the CBD, CBDA, and CBGA content after heating of extracts from hemp materials.

The change of the CBD, CBDA, and CBGA content after heating of extracts from hemp materials in 2012 (in % of the initial content). Courtesy of Journal of Central European Agriculture.

Seed and hull production and potential CBD production in seeds is shown in this table about hemp.

Seed and hull production and potential CBD production in seeds of two hemp varieties (mean ± standard deviation) in 2012. Courtesy of Journal of Central European Agriculture.

Conclusion

The researchers arrived at the following findings: in the case of CBD extraction, raw materials used in fiber production can be used. Industrial hemp when harvested at its flowering stage offers CBD extraction possibilities. Significant raise in CBD content is possible when extracts are heated in decarboxylation ovens, as shown here with the Memmert universal oven, from hemp sources.

For more information on Memmert offerings, in the cannabis process with its marijuana extraction equipment, reach out to the experts and sign up to the newsletter for the latest information.