The properties of Oregano essential oil
by the Doctor Matteo Politi
Origanum vulgare THE.
- Angiosperms
- Lamiaceae
- Origanum
(botanical nomenclature source)
Phytochemical profile
Oregano is an herb of the family Lamiaceae cultivated since ancient times in the Mediterranean area.
More than 20 species are included in the genus Origanum, being O. vulgare L. and O. majorana L. best known for their medicinal and antioxidant activities.
Thymol and carvacrol, which are present in high quantities in the essential oil (78-82%)1, are mainly responsible for its antioxidant properties, while other components implicated in its activity are ρ-cymene and γ-terpinene.2
However, four main groups can be distinguished, commonly called oregano and used as aromatic herbs, namely Greek oregano (Origanum vulgare L. ssp. Hirtum), Spanish Oregano (Coridothymus capitatus), Turkish Oregano (O. onites L.) and Mexican oregano (Lippia graveolens). Greek oregano is typical of the eastern Mediterranean, reported only for some areas of southern Italy.3
Pharmacological activity
The dried leaves of oregano and the inflorescences are used as a human and animal food extremely rich in antioxidant properties.
Furthermore, its essential oil is used for a number of medicinal purposes, such as inhibiting the production of microbial and fungal toxins as well as for anti-inflammatory, analgesic, anti-arthritic, anti-allergic, anticancer, antioxidant, anti-diabetic, cardioprotective, gastroprotective, hepatoprotective and neuroprotective properties.4,5
Antimicrobial activity
Currently, the increasing resistance of microorganisms to synthetic antimicrobials in combination with the emergence of emerging diseases requires the urgent development of new, more effective products. Oregano is one of the richest plant resources in natural antimicrobials.6
The main compounds of oregano essential oil, carvacrol and thymol, are responsible for the characteristic odor, antimicrobial and antioxidant activity; their content may vary depending on the species, harvest season and geographical sources.
These substances as antibacterial agents make the cell membrane permeable due to its impregnation in the hydrophobic domains, with greater effect against gram-positive bacteria.7 Carvacrol is a phenolic monoterpenoid present in large quantities in essential oils, especially of oregano (Common oregano) and thyme (Thymus vulgaris) but in smaller quantities it is present in many other plants.
Carvacrol possesses a broad range of bioactivities useful for clinical applications such as antimicrobial, antioxidant and antitumor activities.
The antimicrobial activity of carvacrol is superior to that of other volatile compounds due to the presence of the free hydroxyl group, hydrophobicity and phenolic moiety.8
Use in animal husbandry
Oregano essential oil has been shown to be a good supplement in animal feed helping to improve the quality of products derived from such types of farming.9–14
Bibliography
1. Alirezalu K, Pateiro M, Yaghoubi M, Alirezalu A, Peighambardoust SH, Lorenzo JM. Phytochemical constituents, advanced extraction technologies and techno-functional properties of selected Mediterranean plants for use in meat products. A comprehensive review. Trends Food Sci Technol. 2020;100:292–306. doi:10.1016/j.tifs.2020.04.010
2. Fasseas MK, Mountzouris KC, Tarantilis PA, Polissiou M, Zervas G. Antioxidant activity in meat treated with oregano and sage essential oils. Food Chem. 2007;106:1188–1194. doi:10.1016/j.foodchem.2007.07.060
3. Elshafie HS, Camele I. An overview of the biological effects of some Mediterranean essential oils on human health. Biomed Res Int. 2017:9268468. doi:10.1155/2017/9268468
4. Pezzani R, Vitalini S, Iriti M. Bioactivities of Origanum vulgare L.: an update. Phytochem Rev. 2017;16:1253–1268. doi:10.1007/s11101-017-9535-z
5. SKOUFOGIANNI E, SOLOMOU AD, DANALATOS NG. Ecology, Cultivation and Utilization of the Aromatic Greek Oregano (Origanum vulgare L.): A Review. Not Bot Horti Agrobot Cluj-Napoca. 2019;47(3):545-552. doi:10.15835/nbha47311296
6. Sakkas H, Papadopoulou C. Antimicrobial activity of basil, oregano, and thyme essential oils. J Microbiol Biotechnol. 2017;27(3):429–438. doi:10.4014/jmb.1608.08024
7. Rodriguez-Garcia I, Silva-Espinoza BA, Ortega-Ramirez LA, et al. Oregano Essential Oil as an Antimicrobial and Antioxidant Additive in Food Products. Crit Rev Food Sci Nutr. 2016;56(10):1717-1727. doi:10.1080/10408398.2013.800832
8. Sharifi-Rad M, Varoni EM, Iriti M, et al. Carvacrol and human health: A comprehensive review. Phyther Res. 2018;32:1675–1687. doi:10.1002/ptr.6103
9. Avila-Ramos F, Pro-Martínez A, Sosa-Montes E, et al. Effects of dietary oregano essential oil and vitamin E on the lipid oxidation stability of cooked chicken breast meat. Poult Ski. 2012;2(1):505-511. doi:10.3382/ps.2011-01731
10. Çabuk M, Eratak S, Alçicek A, Bozkurt M. Effects of herbal essential oil mixture as a dietary supplement on egg production in quail. Sci World J. 2014:573470. doi:10.1155/2014/573470
11. Forte C, Ranucci D, Beghelli D, et al. Dietary integration with oregano (Origanum vulgare L.) essential oil improves growth rate and oxidative status in outdoor-reared, but not indoor-reared, pigs. J Anim Physiol Anim Nutr (Berl). 2017;101:e352–e361. doi:10.1111/jpn.12612
12. Rivaroli DC, Guerrero A, Velandia Valero M, et al. Effect of essential oils on meat and fat qualities of crossbred young bulls finished in feedlots. Meat Ski. 2016;121:278-284. doi:10.1016/j.meatsci.2016.06.017
13. Paraskevakis N. Effects of dietary Greek oregano (Origanum vulgare ssp. hirtum) supplementation on rumen fermentation, enzyme profile and microbial communities in goats. J Anim Physiol Anim Nutr (Berl). 2018;102:701–705. doi:10.1111/jpn.12812
14. Simitzis PE, Symeon GK, Charismiadou MA, Bizelis JA, Deligeorgis SG. The effects of dietary oregano oil supplementation on pig meat characteristics. Meat Ski. 2010;84(4):670-676. doi:10.1016/j.meatsci.2009.11.001