Absolutes of tonka bean, yellow sweet clover, hay and sweet vernal grass (vanilla grass) were analysed. Absolute is a mixture of volatile compounds, obtained by extraction with organic solvents. After reviewing the scientific literature the research was focused on the content of coumarin, since all the above mentioned absolutes contain this compound. Coumarin is used in perfumes, cosmetic, tobacco and food. In Germany, the use of coumarin was forbidden in a certain period due to the assumption that it is carcinogenic. Nowadays maximum quantities of coumarin for a specific application are prescribed. Coumarins are common in botanical families Fabaceae, Asteraceae, Apiaceae and Rutaceae. They can be free or bound in glycosides (monosaccharide is generally glucose). Simple coumarins are antiedemic, venotonic, anti-inflammatory, antispasmodic, sedative and some of them also immunostimulatory. Derivatives of simple coumarines are furanocoumarins and pyranocoumarins. Former are particularly used in the treatment of vitiligo and psoriasis.
Selected absolutes were analysed by gas chromatography coupled with mass spectrometry. Most of the compounds were identified and quantified employing reference compounds. Ethyl melilotate was not available on the market and was therefore synthesised. The composition of absolutes was found to vary considerably between batches, which is the consequence of variability of natural material. The absolute of tonka beans contained the largest proportion of volatile compounds (45.99% and 73.85%) and at the same time the smallest number of compounds identified and quantified. Absolutes of yellow sweet clover contained 36.87% and 55.74% and of sweet vernal grass 53.12% of volatile compounds, respectively. In the absolute of hay the largest number of volatile compounds was identified, but their shares were the lowest (11.53% and 13.52%). Identified volatile compounds were classified as aldehydes, alcohols, esters, ethers, phenols, ketones, acids, lactones, terpenes and terpenoids. Tonka bean and yellow sweet clover absolutes contained the highest concentrations of coumarin 37.35%, 58.75% and 16.63, 11.02%, respectively, followed by the absolutes of hay (0.1775% and 0.06651%) and of sweet vernal grass (0.3015%).
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