In this edition of "Comparatively Speaking," Tony O'Lenick explores the differences between extraction via water-, oil-, fluoro- and silicone-soluble solvents. This column follows previous others defining extraction and different processes for using it.
Extraction is a process that makes use of partition coefficient to remove desirable fractions from a biological matrix. The specific materials extracted are determined by the solubility of those ingredients in the different menstrua (solvents). As an example, one patent application1 describes the extraction from broccoli sprouts of four different active fractions via four different silicone polymer menstrua, as indicated by four Fourier transform infrared (FTIR) spectra. Spectral subtraction of the menstrua allows for the identification of groups present in the extracted materials. Menstrua based on the partition coefficient technology of the described invention thus allow for the rapid screening and effective extraction of this class of materials from broccoli sprouts as well as other cruciferous materials.
Dried and crushed plant material was placed in a filter bag having a pore size of 100 microns. The amount of plant material was 5% by weight, and the silicone-based menstruum comprised 95% of the weight. The menstruum was added to a recirculaton vessel, heated to between 60°C and 90°C, and recirculated through the filter bag for a period of 12 hr. Of the total amount of plant material subjected to extraction, 12.1% of the material went into the various solvents, leaving 87.9% of the plant material behind as insoluble solvent.
Oil-soluble Silicone Extract
The silicone menstruum having alkyl-soluble groups, i.e., alkyl silicone or cetyl dimethicone, extracted 3% of the actives. Based on FTIR, the spectral subtractions were ester, unsaturation, some amine groups and some ketones. The extract changed in color from water-white to pale yellow. The skin feel of the product was quite cosmetically elegant, providing a smooth feel with outstanding glide and spread. The extract of this example could be used as-is; i.e., in the menstruum without further modification, as well as in a topical emulsion systems by methods known to those skilled in the art.
The dimethicone silicone fluid (50 Pa•s) menstruum extracted 0.9% of the plant material. The functional groups present on the FTIR after spectral subtraction were primarily alcohol and ketones. The extract had no color change. The skin feel was cosmetically appealing, providing a dry, powdery feel with outstanding spread. This extract could be used as-is or put into topical emulsion systems. Also, unlike the starting material, the fraction had a distinct UV spectra.
Water-soluble Silicone Extract
The menstruum dimethicone copolyol, i.e. PEG-8 dimethicone, rich in water-soluble groups, was the most effective of the four examples in extracting material; 7% by weight was extracted. The functional groups present on the FTIR after spectral subtraction were alcohols, some esters, a large amount of unsaturation, and some ketones. The extract changed in color from water-white to an intense yellow. The skin feel of the product was cosmetically appealing, providing a smooth feel with outstanding glide and spread. The extract could be used as-is or incorporated into water. The extract has a noticeable sulfur smell, which may be an indication of sulforaphane being present.
Fluoro-soluble Silicone Extract
The fluoro silicone perfluorononyl dimethicone menstruum, rich in fluoro-soluble groups, extracted 1.2% of the plant material. The functional groups present on the FTIR after spectral subtraction were ester and unsaturation. The extract changed in color from a water white to a pale yellow. The skin feel of the product was quite cosmetically appealing, providing a smooth feel with outstanding spread and water-proofing properties.
While solvent-based extraction have some limitations, including their selectivity to extract only active materials that are soluble in the chosen solvent, menstrua based on the partition coefficient technology described allow for the rapid screening and effective extraction of various classes of materials from the same source.
1. US Pat application 20110201836