RESUMO
The aromatic compound (E)-anethol is widely used in the flavor, fragrance, and medicinal industries. This compound is commonly produced through steam distillation of fennel, star anise, and anise seed. Given the cost of production, these natural and authentic essential oils are commonly adulterated with lower-cost natural materials or synthetic alternatives. The current study investigates essential oil profiles (gas chromatography/mass spectrometry) and stable isotope ratios (gas chromatography/isotope ratio mass spectrometry) of the abundant compound (E)-anethol in both authentic reference standards (n = 15) and commercially available samples (n = 30). This multifaceted analytical approach establishes techniques for ensuring the authenticity of essential oil sources of (E)-anethol and was then used to evaluate the current essential oil market sources of (E)-anethol. These findings report that adulteration of (E)-anethol-containing natural products takes various forms, and a multifaceted analytical approach is recommended for authentication. Of the commercial samples analyzed for this report, 27% were adulterated.
RESUMO
Osmorhiza occidentalis Torr. is an essential-oil-bearing plant in the Apiaceae family. Volatile oil was produced through steam distillation (n = 3) of the above ground plant parts and was analyzed by gas chromatography (GC/FID, GC/MS), and gas chromatography/isotope ratio mass spectrometry (GC/IRMS) to establish the essential oil composition and stable isotope profile. The resulting essential oils were found to be comprised of 33 volatile compounds. Prominent volatile compounds include methyl chavicol (avg. 61.6%), (Z)-ß-ocimene (avg. 14.7%), sabinene (avg. 10.5%), and γ-terpinene (avg. 2.8%). Stable isotope values were determined for prominent volatile compounds, including methyl chavicol, (Z)-ß-ocimene, sabinene, and γ-terpinene. Values for δ2H range from -393.479 (avg. sabinene) to -171.516 (avg. methyl chavicol). Those for δ13C range from -35.957 (avg. methyl chavicol) to -30.820 (avg. (Z)-ß-ocimene). The essential oil yield was 0.12% (w/w). The current study establishes for the first time, to the best knowledge of the authors, the essential oil yield, essential oil composition, and stable isotope profile of prominent volatile compounds extracted from the above-ground portions of O. occidentalis. These results provide insight into the volatile chemical composition produced by the plant and provide fundamental data for substantiation of ethnobotanical applications.
RESUMO
Ocimum campechianum Mill. (Peruvian basil) is an essential oil-bearing plant of the Lamiaceae family. Volatile oil produced through steam distillation of Peruvian basil was examined to establish the aromatic and stable isotope profiles of samples (n = 9) from three different cultivated plots in Peru. The resulting essential oils were analyzed by GC/FID, GC/MS, and GC/IRMS. In accordance with findings from other researchers, multiple chemotypes, defined by the most abundant aromatic compounds, exist within these populations. Overall, 55% of samples are the eugenol chemotype (values ranging 15.4-30.2%), 33% are the methyl eugenol chemotype (values ranging 68.1-68.7%), and a single sample is a mixture of both chemotypes, containing high levels of both eugenol (38.1%) and methyl eugenol (8.6%). Stable isotope ratios, δ2H and δ13C, performed on prominent compounds provide supporting data for distinguishing chemotypes. Complete aromatic profiles, stable isotope ratios, and essential oil yield are established for each sample. This study confirms the existence of multiple chemotypes and, for the first time, to the author's best knowledge, establishes stable isotope ratios for O. campechianum essential oil, which proves a useful tool in further investigating plant metabolism and determining essential oil authenticity.