Alessandro Salvatia, Daniele Naviglioa, Armando Zarrellia, Marco Guidab, Federica Carraturob, Monica Galloc

aDipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, 80126 Napoli, Italy,
bDipartimento di Biologia, Università degli Studi di Napoli Federico II, 80126 Napoli, Italy,
cDipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, 80131 Napoli, Italy.

Essential oils, also called “essences”, are natural compounds of plant origin. They are characterized by the presence of volatile substances at room temperature which give the product different odors and fragrances [1]. Characteristics and properties of each essential oil may vary based on the type of mixture that constitutes it, although it is possible to identify some characteristics common to all essential oils. From a chemical point of view, these substances are characterized by a marked volatility (presence of low-boiling compounds) and a very complex composition based mostly on low molecular weight compounds [2,3], among which the most studied and important are terpenes, such as limonene, present in fruits of the citrus family. The uses of essential oils are multiple, ranging from cosmetic use to food formulations, but also for therapeutic purposes, as they possess, albeit to a variable extent, a certain antimicrobial activity [4]. Clearly, in order to preserve their characteristics and properties, it is very important that essential oils are stored correctly. 

Therefore, in this work the shelf life of some samples of essential oils extracted from lemons from Southern Italy was evaluated. For this purpose, commercial samples of essential oils adequately preserved for 25 years were examined, a period which greatly exceeds the shelf life normally suggested to keep the main properties of the oils themselves unchanged. Accordingly, the samples were subjected to a series of determinations, such as GC-FID, NMR and microbiological analyses, and compared with freshly produced oils.

Keywords:  Essential oils, GC, NMR, antimicrobial activity.

References

1. Dhifi W., Bellili S., et al., Medicines (Basel), 3 (2016). DOI: 10.3390/medicines3040025 

2. Naviglio D., Le Grottaglie L., et al., Natural Product Communications, 10 (2015), 1293-1296. DOI: 10.1177/1934578X1501000739 

3. Catauro M., Naviglio D., et al., Journal of Essential Oil Research, 31 (2019), 138-144. DOI: 10.1080/10412905.2018.1540364 

4. Mutlu-Ingok A., Devecioglu D., et al., Molecules 25(20):4711 (2020). DOI: 10.3390/molecules25204711