Alcohol extraction is far superior to any other method of extraction as it extracts the most amount of chemicals compared to any other solvent. Since alcohol is both non-polar and polar, it can dissolve a much wider range of molecules that includes almost all of the plants medicinal oils, polysaccharides, carboxylic acids and other beneficial chemicals. In other words, alcohol dissolves both water and oil soluble chemicals found in the plant where-as carbon dioxide extraction (a.k.a CO2 extraction) can only dissolve the oil soluble chemicals. In terms of keeping the plant whole and together while maintaining the original chemical ratios contained in the plant, alcohol is the only solvent for the job.
Using the method of carbon dioxide extraction (CO2 extraction) results in a very limited extraction of the plant because the extracts of carbon dioxide are non-polar; carbon dioxide extracts are not water-soluble, only oil-soluble. This plays a vital role in bio-availability. Since our bodies are 70% water, oils must be digested by different acids and enzymes to become active. During this digestion process, the active ingredients of the oils are degraded.
In conclusion, Alcohol extracts are far superior to any other method of extraction. It extracts the most amount of chemicals compared to any other solvent making them more bio-available therefore having a greater effect in the body.