Determining the authenticity of methyl salicylate in Gaultheria procumbens L. and Betula lenta L. essential oils using isotope ratio mass spectrometry

Abstract

The essential oils of wintergreen and birch are composed primarily of methyl salicylate. Because this compound can easily be synthesized, wintergreen and birch oils are frequently adulterated. By using Gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry (GC-C/P-IRMS) in conjunction with TC/EA-IRMS, GC-FID, GC-MS, and 14 C radiocarbon dating, criteria will be established that can be used to distinguish authentic and natural wintergreen and birch essential oils from adulterated ones or from synthetic methyl salicylate. Commercially purchased samples were compared to both synthetic 'oil of wintergreen' (methyl salicylate) and to natural birch and wintergreen essential oils obtained from trusted sources or from the steam distillation of fresh plant material. δ 2 H VSMOW , δ 13 C VPDB , and δ 18 O VSMOW IRMS results provide a clear distinction between authentic and adulterated essential oil samples.

Impact of heat stress on foliar biogenic volatile organic compound emission and gene expression in tomato (Solanum lycopersicum) seedlings

“…Emissions of MeSA and TMTT were observed in the sampled tomato plants. Both compounds have been associated with plant physiological stress (Rose et al, 1996;Kant et al, 2004), although some plants, for example, wintergreen (Gaultheria procumbens L.) and sweet birch (Betula lenta L.) are known to store MeSA in their essential oils (Murphy et al, 2021). Sixteen out of the 18 sampled tomato plants (i.e., all except for Summer Set 1 and Black Cherry 1) were emitting detectable amounts of MeSA at ambient temperatures (25 C/30 C) prior to the heat treatment (Figures 4 and 5), while all but one of the plants were emitting some amount of TMTT (Figure 1).…”

Authentication of Fennel, Star Anise, and Anise Essential Oils by Gas Chromatography (GC/MS) and Stable Isotope Ratio (GC/IRMS) Analyses

“…Given the variability of essential oil profiles and the prohibitive costs of natural products, essential oils containing ( E )-anethol are often adulterated with lower-priced natural or synthetically produced alternatives [ 3 , 24 , 25 , 26 ]. To ensure the authentication of natural compounds, gas chromatography/mass spectrometry (GC/MS) and gas chromatography/isotope ratio mass spectrometry (GC/IRMS), among other analytical techniques, have been reported as powerful analytical tools [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. These same researchers have reported that identification of specific marker compounds by GC/MS and stable isotope analysis of prominent compounds assists in detecting adulteration with synthetic compounds and/or distinguishing natural compounds based on the origin of plant species, chemotype, and provenance.…”

“…Stable isotope ratios, δ 2 H and δ13 C, for (E)-anethol prominent commercially available samples (n = 30): anise(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), star anise(27)(28)(29)(30)(31)(32)(33)(34), and fennel (40-50). Samples were analyzed in triplicate to ensure repeatability (δ 2 H values are reported with a standard deviation ≤ 2.0‰ and δ13 C values are reported with a standard deviation ≤ 0.2‰).…”

Botanical Ingredient Forensics: Detection of Attempts to Deceive Commonly Used Analytical Methods for Authenticating Herbal Dietary and Food Ingredients and Supplements

“…Cinnamon bark oil is commonly substituted with the less costly cinnamon leaf oil . Wintergreen and birch oils are known to be adulterated with synthetic methyl salicylate. − This type of adulteration is most commonly detected using a number of stable isotope ratio (e.g., 2 H/ 1 H, 13 C/ 12 C, or 18 O/ 16 O) measurements …”