GC and Spectroscopy Used to Characterize Essential Oil

In a recent study led by scientists from the University of Messina in Messina, Italy, scientists used gas chromatography (GC)-based techniques alongside spectroscopy techniques to help characterize essential oil from Piper gaudichaudianum Kunth, a plant native to Brazil. Their findings were published in the Journal of Chromatography A (1).

Bottles with rosemary essential oil on light background, top view | Image Credit: © New Africa - stock.adobe.com

Various studies have been conducted to unveil the chemical composition of Piper gaudichaudianum, focusing on its diverse biological activities, from antimicrobial to antileishmanial and antitubercular. Species of the genus Piper have antimicrobial potential against different species of bacteria and fungi (2). Piper gaudichaudianum Kunth specifically is used in popular medicine as anti-inflamatory and against liver disorders (3) The essential oil (EO) derived from Piper gaudichaudianum is of specific note, since it has larvicidal, antifungal, anti-inflammatory, anti-edematogenic, and antinociceptive properties (1).

Essential oils are valuable metabolites extracted from parts of plants including leaves, seeds, bark, and roots. Different methods, such as steam distillation and solvent extraction, can be used to extract substances into oils. Essential oils can provide potential health benefits, with some scientists believing they can send chemical messages to parts of the brain that affect mood and emotion (4).

Read More: https://www.chromatographyonline.com/view/using-lc-ms-to-detect-phototoxins-in-essential-oils

In this study, an unknown molecule, which made up to 27% of the entire EO, was detected through gas chromatography–mass spectrometry (GC–MS) analysis necessitating a proper isolation step for further structural elucidation studies. Following the principles of green chemistry, the isolation and collection of target compounds from natural matrices, rather than synthesis, represent a more sustainable approach. The compound of in preparative GC (prep-GC), which minimizes the consumption of solvents and reagents, was used, offering a more environmentally friendly solution. The compound of interest was collected using prep-GC and subsequently structurally elucidated using a multi-technique approach that involved GC–MS, Fourier-transform infrared spectroscopy (FT–IR), and nuclear magnetic resonance (NMR) spectroscopy. FT–IR is a type of infrared (IR) spectroscopy, where all light frequencies are measured simultaneously; this differs from standard IR spectroscopy, where light is divided into its spectral components, and each is measured individually (5). NMR spectroscopy, on the other hand, is a non-destructive and non-invasive that uses the magnetic properties of the nucleus to sense the chemical environment of a nucleus in a molecular structure (6). These were all used to characterize the essential oil of Piper gaudichaudianum Kunth. 76 components were identified using GC–MS analysis, while enantio‑selective multidimensional gas chromatography elucidated the enantiomeric distribution of eight chiral components.

Using NMR spectroscopy, MS, and GC-FT–IR, the unknown molecule was identified as 4-[(3E)‑dec-3-en-1-yl]phenol. This substance, which was already known as gibbilimbol B, previously had no available literature documentation regarding its presence in the essential oil of P. gaudichaudinaum Kunth. Further, its mass spectrum has been unavailable in widely used mass spectrometry databases. With this study, future endeavors will be able to compare activity between P. gaudichaudianum Kunth EO and gibbilimbol B, with the aim of evaluating possible synergic effects on various biological targets.

References

(1) Cucinotta, L.; Rotondo, A.; Coppolino, C.; Irrera, E.; et al. Gas chromatographic techniques and spectroscopic approaches for a deep characterization of Piper gaudichaudianum Kunth essential oil from Brazil. J. Chromatogr. A 2024, 1732, 465208. DOI: 10.1016/j.chroma.2024.465208

(2) Leal, A. L. A. B.; da Silva, M. C.; Silva, A. K. F. E.; et al. Chemical Composition of Piper gaudichaudianum Kunth Essential Oil and Evaluation of its Antimicrobial and Modulatory Effects on Antibiotic Resistance, Antibiofilm, and Cell Dimorphism Inhibitory Activities. 3 Biotech. 2023, 13 (7), 255. DOI: 10.1007/s13205-023-03681-1

(3) Sperotto, A. R. M.; Moura, D. J.; Péres, V. F.; et al. Cytotoxic Mechanism of Piper gaudichaudianum Kunth Essential Oil and its Major Compound Nerolidol. Food Chem. Toxicol. 2013, 57, 57–68. DOI: 10.1016/j.fct.2013.03.013

(4) Acevedo, A. Extraction of Terpenoids from Essential Oils. MJH Life Sciences 2024. https://www.chromatographyonline.com/view/extraction-of-terpenoids-from-essential-oils (accessed 2024-8-12)

(5) What is FTIR Spectroscopy? Agilent Technologies 2024. https://www.agilent.com/en/support/molecular-spectroscopy/ftir-spectroscopy/ftir-spectroscopy-basics-faqs (accessed 2024-8-12)

(6) Nuclear Magnetic Resonance Spectroscopy. Elsevier B.V. 2024. https://www.sciencedirect.com/topics/materials-science/nuclear-magnetic-resonance-spectroscopy (accessed 2024-8-12)