Terpenoids from Essential Oils

Abstract

Essential oils contain terpenoids and phenylpropanoids as major constituents. Terpene‐bearing aromatic plants play an important role in food, flavor, and fragrance. Essential oils rarely reach the consumers in their natural composition. They are adjusted to meet either the desired quality or specification of a legal regulatory body such as BIS and ISO. The adulterants can be inexpensive synthetic or essential oils of another origin, which ultimately leads to a variable product with less demand. In this article, chiral differentiation using enantioselective gas chromatographic technique is described for high‐value chiral terpenes identified in essential oils. The technique is based on the separation of enantiomers in different cyclodextrin‐coated fused silica capillary columns. The chiral distribution of citronellol enantiomers in Rosa damascena and Cympbopogon winterianus showed the presence of opposite images in each oil. R. damascena contained (−)‐citronellol, whereas (+)‐citronellol was recorded in citronella oil. (+)‐Linalool was a unique feature of Lippia alba . On the contrary, Ocimum basilicum possessed pure (−)‐linalool. Camphor was separated in Ocimum spp. and Cinnamomum camphora with exclusive presence of (+)‐enantiomer. Limonene, menthone, menthol, and menthyl acetate were identified as pure (−)‐enantiomers, whereas isomenthone, neomenthol, pulegone, and piperitone as pure (+)‐enantiomers in Indian menthol mint and peppermint oils, respectively. The usefulness of unique chiral signatures in setting up regulatory guidelines for the most traded essential oils is also discussed.

Chitosan-Based Nanoencapsulated Essential Oils: Potential Leads against Breast Cancer Cells in Preclinical Studies

“…Examples of common sesquiterpenes and sesquiterpenoids are α-humulene, β-caryophyllene, patchoulol, and farnesol. Meanwhile, diterpenes, sesterterpenes, triterpenes, sesquarterpenes, and tetraterpenes are rarely detected in EOs due to their low volatility [ 39 , 40 ]. Figure 1 shows the chemical structures of common EO constituents.…”