Qualitative and quantitative analysis of cresols found in maskwio’mi (birch bark extract)

Abstract

Maskwio’mi (Mi’kmaw language for “oil made from birch bark”) is a traditional topical skin medicine of the Mi’kmaq people of Atlantic Canada and is produced in a torrefaction process by heating birch bark (Betula papyrifera, paper birch) inside a metal container in a fire. The resulting viscous, oily mixture is traditionally mixed with goose fat or bear grease to create a topical salve that is subsequently applied to affected skin areas. When birch bark is exposed to high temperatures, pyrolytic chemical processes produce a complex mixture of pharmacologically active compounds, including potentially harmful side products such as ortho-, meta-, and para-cresol. This study discusses the qualitative and quantitative GC-MS analysis of cresols found in maskwio’mi and the challenges of the complex organic matrix. Using caffeine as an internal standard, ortho-, meta-, and para-cresol in birch bark extract were determined to be in the approximate order of 50–1500 ppm range with 3.24 ± 0.09 × 102 ng mg−1 (324 ppm), 8.7 ± 1.0 × 102 ng mg−1 (87 ppm), and 12.4 ± 1.6 × 102 ng mg−1 (1240 ppm), respectively, and thus suitable by Health Canada and FDA cosmetics regulation standards when the extract is co-formulated in creams to concentrations of 0.1–5 wt.% for topical use.