Determining thymol and carvacrol by reversed-phase high-performance liquid chromatography

Liquid chromatography–mass spectrometry analysis of carvacrol in chicken tissues

Introduction

Carvacrol is an essential oil derived from oregano that is used as a natural additive to improve the efficiency of livestock nutrition. Residues of natural additives such as carvacrol should be monitored in food of animal origin to ensure consumer safety. The aim of this study was to appraise the quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled with liquid chromatography and mass spectrometry as a means of carvacrol analysis in chicken tissue.

Material and Methods

A 5 ± 0.05 g portion of plasma, lung, muscle and liver was mixed for 15 min with 5 mL of 1-butanol and 20 mL of water, then centrifuged. A 0.5 mL volume from the top layer was transferred, then 60 mg of octadecylsilane sorbent, 30 mg of primary and secondary amine and 200 mg of MgSO₄ were added. The extract was mixed and centrifuged. The top layer was filtered and then transferred to an autosampler vial for analysis by high-performance liquid chromatography–tandem mass spectrometry.

Results

The limit of detection was calculated at 0.06 μg g⁻¹ and the limit of quantification was 0.2 μg g⁻¹, with relative standard deviation repeatability and reproducibility below <20%.

Conclusion

The validation results showed that this method could be a good alternative to determination of carvacrol by gas chromatography and is suitable for carvacrol analysis in different matrices.

Second-order electrochemical data generation to quantify carvacrol in oregano essential oils

A novel analytical method using voltammetric second-order modeling based on multivariate curve resolution-alternating least-square (MCR-ALS) is presented for the first time for the quantitation of carvacrol (CAR) in oregano essential oils (OEO). The second-order cyclic voltammetry data were generated on the basis that CAR shows a diffusional system. Thus, the scan rate (v) was used as a second instrumental mode and cyclic voltammograms at different v were acquired for a single sample, generating the second-order data. CAR determination was performed in presence of thymol, included as a potential interferent. Results demonstrated that MCR-ALS successfully exploited the second-order advantage and the recoveries were not statistically different than 100%. The limits of detection and quantitation were estimated using the MCR-ALS which were 6.27 × 10^-5°mol°L^-1°and 1.90 × 10^-4°mol L^-1, respectively. Finally, the developed methodology was implemented to quantify of CAR in OEO samples.

Ultrasonic-Assisted Thymol and Carvacrol Extraction from Za’atar Leaves Using Cold-Pressed Sesame Oil

Thymol and carvacrol found in Origanum syriacum “Za’atar” plant leaves have triggered interest among researchers for their natural antimicrobial and antifungal properties. However, their applications in modern pharmaceutical and cosmetic industries as natural preservatives remain challenging. In this research, extraction of thymol and carvacrol from Za’atar leaves has been investigated using the ultrasonic-assisted method and the use of sesame oil as the primary extraction solvent compared with other vegetable oils including sunflower and olive oils. In addition, a high-performance liquid chromatography (HPLC) analytical method was developed by using a C8 column and 0.05% trifluoroacetic acid as a buffering agent. The method was validated for specificity, linearity, repeatability, accuracy, and robustness for the analysis of the content of the two terpenes thymol and carvacrol in different Za’atar extracts. Using the validated analytical method, thymol and carvacrol content results revealed the best vegetable oil for extraction. Results showed that sesame oil had the highest content of thymol and carvacrol, followed by sunflower oil, and the least amount obtained by using olive oil. A consistent extraction result opens an opportunity for application in the pharmaceutical and cosmetic industries. For this reason, the essential extraction key parameters that influence the final content of thymol and carvacrol were evaluated. The highest impact originated from the quality and volume of sesame oil. Cold-pressed sesame oil resulted in a 23% higher content of thymol and decreased amount of carvacrol. It was found that wetting the Za’atar leaves powder with sesame oil was enough for extraction; any additional sesame oil volume dilutes the extracted sample. The second impact was the Za’atar cultivation conditions; less than 10% difference of thymol and carvacrol content was observed within Za’atar of Hebron origin. Finally, the origin of sesame seeds used for sesame oil production had the least impact.

Ultrasonic-Assisted Thymol and Carvacrol Extraction from Za’atar Leaves Using Cold-Pressed Sesame Oil

Thymol and carvacrol found in Origanum syriacum “Za’atar” plant leaves have triggered interest among researchers for their natural antimicrobial and antifungal properties. However, their applications in modern pharmaceutical and cosmetic industries as natural preservatives remain challenging. In this research, extraction of thymol and carvacrol from Za’atar leaves has been investigated using the ultrasonic-assisted method and the use of sesame oil as the primary extraction solvent compared with other vegetable oils including sunflower and olive oils. In addition, a high-performance liquid chromatography (HPLC) analytical method was developed by using a C8 column and 0.05% trifluoroacetic acid as a buffering agent. The method was validated for specificity, linearity, repeatability, accuracy, and robustness for the analysis of the content of the two terpenes thymol and carvacrol in different Za’atar extracts. Using the validated analytical method, thymol and carvacrol content results revealed the best vegetable oil for extraction. Results showed that sesame oil had the highest content of thymol and carvacrol, followed by sunflower oil, and the least amount obtained by using olive oil. A consistent extraction result opens an opportunity for application in the pharmaceutical and cosmetic industries. For this reason, the essential extraction key parameters that influence the final content of thymol and carvacrol were evaluated. The highest impact originated from the quality and volume of sesame oil. Cold-pressed sesame oil resulted in a 23% higher content of thymol and decreased amount of carvacrol. It was found that wetting the Za’atar leaves powder with sesame oil was enough for extraction; any additional sesame oil volume dilutes the extracted sample. The second impact was the Za’atar cultivation conditions; less than 10% difference of thymol and carvacrol content was observed within Za’atar of Hebron origin. Finally, the origin of sesame seeds used for sesame oil production had the least impact.

Ultrasound combined with manganese-oxide nanoparticles loaded on activated carbon for extraction and pre-concentration of thymol and carvacrol in methanolic extracts of Thymus daenensis, Salvia officinalis, Stachys pilifera, Satureja khuzistanica, and mentha, and water samples

A dispersive micro solid-phase extraction (DMSPE) technique was developed using manganese-oxide nanoparticles loaded on activated carbon (Mn₃O₄-NPs-AC) as an effective sorbent combined with ultrasound for the extraction and determination of a trace amount of thymol and carvacrol in methanolic extracts of Thymus daenensis, Salvia officinalis, Stachys pilifera, Satureja khuzistanica and mentha, and water samples.

Chemistry and multibeneficial bioactivities of carvacrol (4-isopropyl-2-methylphenol), a component of essential oils produced by aromatic plants and spices

Aromatic plants produce organic compounds that may be involved in the defense of plants against phytopathogenic insects, bacteria, fungi, and viruses. One of these compounds, called carvacrol, which is found in high concentrations in essential oils such as oregano, has been reported to exhibit numerous bioactivities in cells and animals. This integrated overview surveys and interprets our present knowledge of the chemistry and analysis of carvacrol and its beneficial bioactivities. These activities include its antioxidative properties in food (e.g., lard, sunflower oil) and in vivo and the inhibition of foodborne and human antibiotic-susceptible and antibiotic-resistant pathogenic bacteria, viruses, pathogenic fungi and parasites, and insects in vitro and in human foods (e.g., apple juice, eggs, leafy greens, meat and poultry products, milk, oysters) and food animal feeds and wastes. Also covered are inhibitions of microbial and fungal toxin production and the anti-inflammatory, analgesic, antiarthritic, antiallergic, anticarcinogenic, antidiabetic, cardioprotective, gastroprotective, hepatoprotective, and neuroprotective properties of carvacrol as well as metabolic, synergistic, and mechanistic aspects. Areas for future research are also suggested. The collated information and suggested research might contribute to a better understanding of agronomical, biosynthetic, chemical, physiological, and cellular mechanisms of the described health-promoting effects of carvacrol, and facilitate and guide further studies needed to optimize the use of carvacrol as a multifunctional food in pure and encapsulated forms, in edible antimicrobial films, and in combination with plant-derived and medical antibiotics to help prevent or treat animal and human diseases.