Patch testing with serial dilutions and thin-layer chromatograms of oak moss absolutes containing high and low levels of atranol and chloroatranol

Results of patch testing with five fragrance materials hitherto not tested: A dose-finding study in the clinical population

BACKGROUND

Quantitative risk assessment (QRA) for skin sensitization is used to derive safe use levels of sensitising fragrance ingredients in products. Post-marketing surveillance of the prevalence of contact allergy to these ingredients provides relevant data to help evaluate the performance of these measures.

OBJECTIVES

To determine a suitable patch test concentration for five fragrance materials that had hitherto not been tested on a regular basis. These concentrations are then to be used in a surveillance study with patch testing consecutive patients over an extended monitoring period.

MATERIALS AND METHODS

Furaneol, CAS.3658-77-3; trans-2-hexenal, CAS.6728-26-3; 4,8-dimethyl-4,9-decadienal, CAS.71077-31-1; longifolene, CAS.475-20-7; benzaldehyde, CAS.10052-7, were patch tested with other fragrance allergens in four clinics. Patch testing was conducted in three rounds, starting with the lowest concentrations of the five ingredients. The doses were increased in the subsequent rounds if no late-appearing positive reactions and virtually no irritant reactions were reported.

RESULTS

Overall, 373 patients were tested. No positive allergic reaction was reported to the five ingredients. Patch test results of other fragrance allergens are reported.

CONCLUSIONS

The highest test concentrations are each considered safe for patch testing consecutive patients. Further surveillance based on these preparations will evaluate the hypothesis that QRA-driven consumer product levels of these fragrances can prevent sensitization.

Simultaneous patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes ‐ an update from southern Sweden

Background

Regularly updating the prevalence of fragrance contact allergy (CA) is important. Patch testing with fragrance markers in the baseline series and the ingredients of fragrance mixes (FMs) is still debated.

Objectives

To update the prevalence and clinical characteristics of patients with fragrance CA. To establish the results of patch testing with individual allergens of FMs.

Methods

A retrospective analysis of 3539 patients with dermatitis who were patch tested with the baseline series and FMs ingredients during 2016 to 2020 was performed.

Results

The prevalence of fragrance CA was 13%. About 10% of these patients with fragrance CA would be missed if the individual ingredients were not tested. Unlike hydroxyisohexyl 3‐cyclohexene carboxaldehyde, there was no decreasing trend of CA to Evernia prunastri (oakmoss) extract after the EU regulation came into force. Patients with CA from only one ingredient of the mixes or having a weak positive reaction to the ingredients were significantly missed when tested with only the fragrance markers in the baseline series.

Conclusions

Patch testing with individual fragrance allergens is crucial for experts to expand knowledge in the fragrance CA field. The concentrations of the allergens in FMs may need to be adjusted to detect patients with fragrance CA, since some were significantly overlooked.

Antimicrobial and antioxidant activity of Evernia prunastri extracts and their isolates

Lichens are symbiotic organisms formed by a fungus and one or more photosynthetic partners which are usually alga or cyanobacterium. Their diverse and scarcely studied metabolites facilitate adaptability to extreme living conditions. We investigated Evernia prunastri (L.) Ach., a widely distributed lichen, for its antimicrobial and antioxidant potential. E. prunastri was sequentially extracted by hexane (Hex), dichloromethane (DCM) and acetonitrile (ACN) that were screened for their antioxidant and antimicrobial (against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans) activities. The Hex extract possessed the highest antioxidant capacity (87 mg ascorbic acid/g extract) corresponding to the highest content of phenols (73 mg gallic acid/g extract). The DCM and Hex extracts were both active against S. aureus (MICs of 4 and 21 µg/ml, respectively) but were less active against Gram-negative bacteria and yeast. The ACN extract exhibited activity on both S. aureus (MIC 14 µg/ml) and C. albicans (MIC 38 µg/ml) and was therefore further fractionated by silica gel column chromatography. The active compound of the most potent fraction was subsequently characterized by 1H and 13C-NMR spectroscopy and identified as evernic acid. Structural similarity analyses were performed between compounds from E. prunastri and known antibiotics from different classes. The structural similarity was not present. Antioxidant and antimicrobial activities of E. prunastri extracts originate from multiple chemical compounds; besides usnic acid, most notably evernic acid and derivatives thereof. Evernic acid and its derivatives represent possible candidates for a new class of antibiotics.

Laboratory Techniques for Identifying Causes of Allergic Dermatitis

This article reviews the laboratory's role in identifying causes of chemical-induced allergic dermatitis. Several topics will be discussed. Allergen hazard identification refers to testing of chemicals for their sensitization potential. Animal-based, in silico, in chemico, and in vitro tests have been developed to identify the skin sensitization hazard of potential chemical allergens, but only a few of these are accepted by regulatory agencies. Laboratory investigations have also evaluated the stability of several commercially available allergic contact dermatitis patch tests. Such studies are considered product testing and are usually conducted in analytical chemistry laboratories.

Are atranols the only skin sensitizers in oakmoss? A systematic investigation using non-animal methods

Oakmoss and treemoss absolutes are the major natural extracts of concern as potential sources of skin sensitizers in cosmetics and personal care products (PCP). Two single constituents, atranol and chloroatranol, have been identified as primary culprits in both lichens, and industrial self-regulation has been proposed to limit their contents to less than 100 ppm. Nonetheless, evidence points to the presence of additional candidate skin sensitizers in these multicomponent extracts. These observations, along with a lack of data from non-animal alternative methods and the chemical variability of commercial absolutes, prompted further investigation of oakmoss absolute along with altranol-like compounds in these extracts. The major chemical constituents of a commercial sample were identified by two independent analytical techniques, GC-MS and HPLC-DAD-MS. The crude oakmoss extract and pure compounds were assayed with two in chemico methods (HTS-DCYA and DPRA) to gauge their chemical reactivity. Activation of inflammatory responses in vitro was also investigated by KeratinoSens™ and human cell line activation tests (h-CLAT). Based on weight of evidence, orcinol, ethyl orsellinate, and usnic acid were classified as candidate sensitizers, along with both atranols and oakmoss extract.