Fuente: PubMed "propolis" Dermatitis. 2026 Aug 14:17103568261476312. doi: 10.1177/17103568261476312. Online ahead of print.ABSTRACTBACKGROUND: Propolis, Myroxylon pereirae resin (balsam of Peru), and colophonium are complex botanical materials that frequently co-react when patch tested. Detailed knowledge of their compositions may help explain the co-reactivity pattern and identify the haptens responsible for positive patch tests.OBJECTIVE: To study the compositions of propolis, M. pereirae resin, and colophonium used for patch testing and assess whether they contain identical ingredients.METHODS: The ingredients of 3 samples of propolis, 2 of M. pereirae resin and 2 of colophonium used for preparing patch test preparations by Chemotechnique and SmartPractice (brand Allergeaze) were analyzed using gas chromatography-mass spectrometry.RESULTS: Major ingredients in Brazilian propolis were non-volatile fatty materials; in Chinese propolis tectochrysin, pinostrobin, pinocembrin, and p-vinylguaiacol; in M. pereirae resin benzyl benzoate, benzyl cinnamate and nerolidol; in colophonium Chemotechnique isoabienol, β-caryophyllene, sandaracopimarinal, sandaracopimarinol and longifolene; in colophonium Allergeaze lupeol acetate, longifolene, sandaracopimarinol, abietinal and isoabienol. Only 11 chemicals were present in 2 materials, none in all 3.CONCLUSIONS: Very few identical chemicals were found in propolis, M. pereirae resin, and colophonium. The results do not support the notion that the frequently observed co-reactivity to these complex natural materials can be explained by identical chemicals detected in this study.PMID:42596784 | DOI:10.1177/17103568261476312