GC-MS-based metabolomics for the detection of adulteration in oregano samples

Oregano is one of the most used culinary herb and it is often adulterated with cheaper plants. In this study, GC-MS was used for identification and quantification of metabolites from 104 samples of oregano (Origanum vulgare and O. onites) adulterated with olive (Olea europaea), venetian sumac (Cotinus coggygria) and myrtle (Myrtus communis) leaves, at five different concentration levels. The metabolomics profiles obtained after the two-step derivatization, involving methoxyamination and silanization, were subjected to multivariate data analysis to reveal markers of adulteration and to build the regression models on the basis of the oregano-to-adulterants mixing ratio. Orthogonal partial least squares enabled detection of oregano adulterations with olive, Venetian sumac and myrtle leaves. Sorbitol levels distinguished oregano samples adulterated with olive leaves, while shikimic and quinic acids were recognized as discrimination factor for adulteration of oregano with venetian sumac. Fructose and quinic acid levels correlated with oregano adulteration with myrtle. Orthogonal partial least squares discriminant analysis enabled discrimination of O. vulgare and O. onites samples, where catechollactate was found to be discriminating metabolite

Latex metabolome of Euphorbia species: geographical and inter-species variation and its proposed role in plant defense against herbivores and pathogens

Plant science

NMR-based metabolomics for frauds detection and quality control of oregano samples

In this work 1H NMR metabolomics has been employed for quality control of oregano samples. NMR data and morphological analysis (MA) were combined by PCA, obtaining a model able to individuate non-marketable samples, and to distinguish between the two marketable oregano species (Origanum vulgare and O. onites) on the basis of their metabolomic profile. Through this approach distinctive biomarkers of the two species were found, namely apigenin and p-cymene for O. onites, and salvianolic acid B for O. vulgare. Furthermore, the percentage of the samples’ impurity (evaluated by MA) and the metabolomic profiles were correlated by OPLS models, which showed that, in addition to the species-specific biomarkers, thymol and rosmarinic acid (common to both marketable species) strongly correlate to oregano degree of purity. Cistus was one of the most frequent contaminants, thus, a further OPLS model, able to detect the degree of cistus contamination in oregano samples, was also built

Evaluation of nutritional composition and antioxidant activity of Borage (Echium amoenum) and Valerian (Valerian officinalis)

The nutritional composition and antioxidant activity (in aqueose and solvent extracts) of two medicinal plants of Iranian origin Borage (Echium amoenum) and Valerian (Valerian officinalis) used as tea were determined. Samples were analyzed for antioxidant components viz. polyphenols, vitamin C, β carotene, flavonoids, anthocyanins and tannins. Antioxidant assays such as free radical scavenging activity, reducing power and total antioxidant activity were carried out for ethanol, methanol, acetone, 80% methanol and 80% ethanolic extracts. In borage highest and least activity was observed in water and acetone extract respectively in all assays. In Valerian, 80% methanolic extract showed highest activity in reducing power and free radical scavenging activity assay. Total polyphenols in borage and valerian were 1,220 and 500 mg in ethanolic extracts and 25 and 130 mg in acetonic extracts respectively. Total carotenoids and vitamin C contents were 31.6 and 133.69 mg and 51.2 and 44.87 mg for borage and valerian respectively. Highest amount of tannins were extracted in 80% methanolic extract. It can be concluded that borage and valerian exhibited antioxidant activity in all extracts. The antioxidant activity could be attributed to their polyphenol and tannin and flavonoids contents. In all assays borage showed higher activity than valerian