Contact allergy to oak moss: search for sensitizing molecules using combined bioassay-guided chemical fractionation, GC-MS, and structure-activity relationship analysis

Abstract

In addition to pure synthetic fragrance materials several natural extracts are still in use in the perfume industry. Among them oak moss absolute, prepared from the lichen Evernia prunastri (L.) Arch., is considered a major contact sensitizer and is therefore included in the fragrance mix used for diagnosing perfume allergy. The process of preparing oak moss absolute has changed during recent years and, even though several potential sensitizers have been identified from former benzene extracts, its present constituents and their allergenic status are not clear. In the study reported here, we applied a method developed for the identification of contact allergens present in natural complex mixtures to oak moss absolute. The method is based on the combination of bioassay-guided chemical fractionation, gas chromatography-mass spectrometry analysis and structure-activity relationship studies. Our first results showed that atranol and chloroatranol, formed by transesterification and decarboxylation of the lichen depsides, atranorin and chloroatranorin, during the preparation of oak moss absolute, are strong elicitants in most patients sensitized to oak moss. Methyl-beta-orcinol carboxylate, a depside degradation product and the most important monoaryl derivative of oak moss from an olfactory standpoint, was also found to elicit a reaction in most patients.

The Antibacterial Activity of Compounds Isolated from Oakmoss against <i>Legionella pneumophila</i> and Other <i>Legionella</i> spp.

“…extracts have been identified previously, including atranol (compound 3), chloroatranol (compound 19), atraric acid (compound 7), everninate (compound 11), haematommate (compound 13), orsellinates (compounds 4, 6, 8) and lecanorin (compound 5). [1][2][3][4] The antimicrobial activity of these compounds against various fungi and Gram-positive and Gram-negative bacteria has also been demonstrated in previous reports. 13,14) However, an examination of the antibacterial activity of these oakmoss components against L. pneumophila and Legionella spp.…”

A liquid chromatography‐mass spectrometric method for the determination of oak moss allergens atranol and chloroatranol in perfumes

“…Atranol and chloroatranol of >99% purity were synthesized according to classical organic methods [9]. Acetone (glass distilled grade) was from Rathburn (Walkeburn, UK) and acetonitrile (HPLC grade) was from Merck (Darmstadt, Germany).…”

“…Atranol and chloroatranol (Figure 1), formed by transesterification and decarboxylation of lichen depsides atranorin and chloroatranorin during the preparation of oak moss absolute, were found to be the strongest elicitants in most patients sensitized to oak moss [9]. The concentration of atranol and chloroatranol in the oak moss sample used for the study was estimated to be 2.1% and 0.9% respectively [9].…”

“…The compounds formed by transesterification of atranorin and chloroatranorin during the oak moss absolute preparation, such as ethyl chlorohematommate (Figure 1), have also been shown to be allergenic [8]. We have recently reinvestigated the sensitizing molecules in oak moss absolute using combined bioassay-guided chemical fractionation, gas chromatography (GC)-mass spectrometry (MS) and structureactivity relationships analysis [9]. Atranol and chloroatranol (Figure 1), formed by transesterification and decarboxylation of lichen depsides atranorin and chloroatranorin during the preparation of oak moss absolute, were found to be the strongest elicitants in most patients sensitized to oak moss [9].…”

“…We have recently reinvestigated the sensitizing molecules in oak moss absolute using combined bioassay-guided chemical fractionation, gas chromatography (GC)-mass spectrometry (MS) and structureactivity relationships analysis [9]. Atranol and chloroatranol (Figure 1), formed by transesterification and decarboxylation of lichen depsides atranorin and chloroatranorin during the preparation of oak moss absolute, were found to be the strongest elicitants in most patients sensitized to oak moss [9]. The concentration of atranol and chloroatranol in the oak moss sample used for the study was estimated to be 2.1% and 0.9% respectively [9].…”