Carvacrol

Natural occurrence

Carvacrol is present in the essential oil of Origanum vulgare (oregano), oil of thyme, oil obtained from pepperwort, and wild bergamot. The essential oil of thyme subspecies contains between 5% and 75% of carvacrol, while Satureja (savory) subspecies have a content between 1% and 45%. Origanum majorana (marjoram) and Dittany of Crete are rich in carvacrol, 50% and 60–80% respectively.

It is also found in tequila and Lippia graveolens (Mexican oregano) in the verbena family.

Sources

• Coleus amboinicus
• Lavandula multifida
• Lepidium
• Lippia graveolens
• Monarda didyma
• Monarda fistulosa
• Nigella sativa
• Origanum compactum
• Origanum dictamnus
• Origanum majorana
• Origanum microphyllum
• Origanum minutiflorum
• Origanum onites
• Origanum scabrum
• Origanum syriacum
• Origanum vulgare
• Plectranthus amboinicus
• Satureja
• Satureja thymbra
• tequila
• Thymbra spicata
• oil of thyme
• Thymus glandulosus

Synthesis and derivatives

Carvacrol may be synthetically prepared by a number of routes. The fusion of cymol sulfonic acid with caustic potash results in desulfonation. By the action of nitrous acid on 1-methyl-2-amino-4-propyl benzene, one effects diazotization. Prolonged heating of camphor and iodine or carvone with glacial phosphoric acid have also been demonstrated. The dehydrogenation of carvone with a palladium-carbon catalyst has been established.

It has also been prepared by transalkylation of isopropylated cresols.

It is extracted from Origanum oil by means of a 50% potash solution. It is a thick oil that sets at -20 °C to a mass of crystals of melting point 0 °C, and boiling point 236–237 °C. Oxidation with ferric chloride converts it into dicarvacrol, whilst phosphorus pentachloride transforms it into chlorcymol.

Antimicrobial effects

In vitro, carvacrol has antimicrobial activity against 25 different phytopathogenic bacteria and strains including: Cladosporium herbarum, and fungi such as Fusarium verticillioides/F. moniliforme, Rhizoctonia solani/R. solani, Sclerotinia sclerotiorum, and Phytophthora capsici.

Compendial status

• British Pharmacopoeia{{cite web |access-date=29 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20090411071437/http://www.pharmacopoeia.co.uk/pdf/2009_index.pdf |archive-date=11 April 2009

References

1. "Carvacrol data sheet from Sigma-Aldrich".
2. (2014). "Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book)". [[Royal Society of Chemistry.
3. (2000). "Antimicrobial activity of carvacrol toward ''Bacillus cereus'' on rice". Journal of Food Protection.
4. {{EB1911
5. (November 2016). "Winter savory: Supercritical carbon dioxide extraction and mathematical modeling of extraction process". The Journal of Supercritical Fluids.
6. (2004). "Constituents of aromatic plants: Carvacrol". Fitoterapia.
7. (2008). "Characterization of volatile compounds from ethnic ''Agave'' alcoholic beverages by gas chromatography-mass spectrometry". Food Technology and Biotechnology.
8. (1993). "New Crops". Wiley.
9. (2010). "Gas chromatography, sensory analysis and electronic nose in the evaluation of black cumin (''Nigella sativa'' L.) aroma quality". Herba Polonica.
10. (2009). "Liposomal incorporation of carvacrol and thymol isolated from the essential oil of ''Origanum dictamnus'' L. and ''in vitro'' antimicrobial activity". Food Chemistry.
11. (2008). "Acaricidal efficacy of ''Origanum onites'' L. essential oil against ''Rhipicephalus turanicus'' (Ixodidae)". Parasitology Research.
12. (1993). "Volatile flavour components of Sicilian ''Origanum onites'' L.". Flavour and Fragrance Journal.
13. (2001). "Composition and antimicrobial activity of the essential oils of two ''Origanum'' species". Journal of Agricultural and Food Chemistry.
14. (2011). "Variation in antibacterial activity, thymol and carvacrol contents of wild populations of ''Thymus daenensis'' subsp. ''daenensis'' Celak". Plant Omics.
15. (1998). "Trace elements and essential oil composition in chemotypes of the aromatic plant ''Origanum vulgare''". Journal of Radioanalytical and Nuclear Chemistry.
16. (2010). "Composition of oregano essential oil (''Origanum vulgare'') as affected by drying method". Journal of Food Engineering.
17. (2003). "Chemical composition and antifungal activity of essential oils of seven Moroccan Labiatae against ''Botrytis cinerea'' Pers: Fr.". Journal of Ethnopharmacology.
18. (2000). "Phenol Derivatives".
19. (2006). "Final report on the safety assessment of sodium ''p''-chloro-''m''-cresol, ''p''-chloro-''m''-cresol, chlorothymol, mixed cresols, ''m''-cresol, ''o''-cresol, ''p''-cresol, isopropyl cresols, thymol, ''o''-cymen-5-ol, and carvacrol". International Journal of Toxicology.
20. (2020-06-02). "Combined Application of Bacteriophages and Carvacrol in the Control of Pseudomonas syringae pv. actinidiae Planktonic and Biofilm Forms". MDPI AG.