Chromatography-mass spectrometry-based identification of triterpenes and phenolic compounds in Maskwio’mi (Betula papyrifera Marshall bark extract)

Abstract

Maskwiomi is a traditional topical treatment used by the Mikmaq people to treat a variety of skin conditions, including eczema and psoriasis. It is typically obtained through the pyrolysis of Betula papyrifera Marshall (paper birch) bark via a can-over-can method. To replicate those conditions under controlled settings, a pyrolysis reactor system developed by Dr. Bierenstiel was used to recreate the production of maskwio`mi in the laboratory. The resulting bio-oil, also referred to as an extract, is formed of a complex mixture, containing hundreds of organic compounds, which makes it challenging to characterize. Chromatography coupled with mass spectrometry is the common technique used for bio- oil composition analysis. This approach has been applied to Betula species analysis, which led to the identification and subsequent isolation of bioactive compounds, including triterpenoids and phenolic compounds. Although some of these compounds can have therapeutic effects, certain phenolic compounds, such as cresols, are recognized as environmental pollutants due to their toxicity and potentially harmful effect on humans and animals, which necessitates their accurate identification and quantification in bio-oil samples. This thesis presents the identification and quantification of phenolic compounds and lupane-type triterpenes. First, the concentrations of ortho-, meta-, and para-cresol were found to be from 324 to 1,240 mg/L using a full-scan GC-MS method. Selected reaction monitoring (SRM) was employed to quantify nine compounds, which ranged from 192 to 5,909 mg/L. Furthermore, betulin and betulinic acid were quantified at concentrations of 2,411 ± 45 ppm and 199 ± 8 ppm using a UHPLC-MS method.