1. Extraction of pant compounds to isolate beneficial components has been occurring for hundreds of years. Reportedly, Cannabis we first extracted in 1840. Phenols and flavonoids are the most desirable compounds present in the plant.
2. Cannabinoids are a less common form of phenolic compound. In Cannabis, these compounds are most highly concentrated in the female flowers.
3. Other works have shown that the primary cannabinoids present in the flowers have demonstrated medicinal potential.
4. Although, may collection methods exist, capturing the Cannabinoids is, quote - made complicated due to their sensitivity to various process parameters such as temperature as well as the coextraction of other undesirable components - unquote.
5. Typical methods of extraction require significant amounts of time, materials, and equipment; recently, quote - a number of non conventional techniques have been ... focused on which include extractions assisted by ultrasound, microwave, enzymes, pulsed electric field, supercritical fluid extraction and pressurized liquid extraction - unquote.
6. Ultrasonication has been successfully applied to the extraction of bioactive compounds. It uses high frequency sound waves to induce cavitation in the target solution. This cavitation unleashes a highly targeted energy at a cellular level allowing the solvent to more easily dissolve the compounds of interest.
7. This study seeks to investigate the viability of using ultrasonication to speed the extraction of Cannabinoids from the flowers of Cannabis sativa L., specifically a Hemp strain containing less than 1.0 percent THC.
8. The samples to be tested were collected from the, quote - top portion including the flowers, leaves, and seed husks - unquote, harvested the prior summer, dried and stored in a dark location.
9. Methanol was the solvent of choice for this study and a Tesla 150 WS probe sonicator was used at a frequency of 20kHz with a max power of 150 watts.
10. Test extractions were performed on 2.5 gram samples dissolved in differing methanol-water solutions. They were subjected to ultrasonication at powers of 90, 120, and 150 watts, over differing time allotments.
11. Spectrophotometry and mass spectrometry were used to quantify the amount of Cannabinoids present in the samples.
12. A control extraction was also performed by soaking a sample in 50 percent methanol for half an hour.
13. Experiments indicated that increasing either the extraction time or the solvent concentration each had a positive effect on extract yield.
14. Increasing the power of the ultrasonication did not have a positive effect on total phenolic content (TPC), and over longer periods of time may have degraded some Cannibinoids thus reducing overall TPC.
15. The total flavinoid content of the extract was not maximized under quite the same conditions as the overall TPC maximization. The maximum flavinoid content was observed at, quote - 10 min, 120 W power, and 50 percent methanol - unquote. Increased solvent concentration had a negative impact on flavinoid concentration, where as ultrasonication power had no apparent effect.
16. Overall extraction yield was improved by increased ultrasonication power, increased time, and decreased solvent concentration.
17. In comparison to the control extraction, the ultrasonicated trials were at least twice as effective in all measured areas. The TPC, TF, and total yield produced in the ultrasonication trials were each double that of the control extraction.
18. The author concludes that ultrasonication - assisted solvent extraction is a viable means of improving extraction efficiency which may allow for a reduction in solvent and process time resources.
Source: Agarwal C, Máthé K, Hofmann T, Csóka L. Ultrasound-Assisted Extraction of Cannabinoids from Cannabis Sativa L. Optimized by Response Surface Methodology. Journal of Food Science. 2018;83(3):700-710. doi:10.1111/1750-3841.14075.
Review by: SP