Mint-Scented Species in Lamiaceae: An Abundant and Varied Reservoir of Phenolic and Volatile Compounds.

This investigation aimed to identify the most favorable cultivar based on plant metabolites for potential targeted cultivation in the pharmaceutical industry. The analysis revealed the presence of 19 individual phenolics and 80 individual volatiles across the cultivars, a breadth of data not previously explored to such an extent. Flavones emerged as the predominant phenolic group in all mint-scented cultivars, except for peppermint, where hydroxycinnamic acids dominated. Peppermint exhibited high concentrations of phenolic acids, particularly caffeic acid derivatives and rosmarinic acid, which are known for their anti-inflammatory and antioxidant properties. Luteolin-rich concentrations were found in several mint varieties, known for their antioxidative, antitumor, and cardio-protective properties. Swiss mint and spearmint stood out with elevated levels of flavanones, particularly eriocitrin, akin to citrus fruits. Monoterpene volatiles, including menthol, camphor, limonene, and carvone, were identified across all cultivars, with Swiss mint and spearmint exhibiting the highest amounts. The study underscores the potential for targeted cultivation to enhance volatile yields and reduce agricultural land use. Notably, chocolate mint demonstrated promise for volatile content, while apple mint excelled in phenolics, suggesting their potential for broader agricultural, pharmaceutical, and food industry production.

Changes in the Aroma Profile and Phenolic Compound Contents of Different Strawberry Cultivars during Ripening.

Secondary metabolites, namely, phenolic and volatile organic compounds, contribute to the nutritional and organoleptic quality of the strawberry fruit. This study focuses on the changes in the content of phenolic compounds and volatile organic compounds during the ripening, from green to overripe fruit, of five strawberry cultivars ('Asia', 'CIVN 766', 'Aprica', 'Clery', and 'Malwina'). Additionally, these changes are compared with the colour of the fruit and peroxidase and polyphenol oxidase activity. Our results show that the accumulation of secondary metabolites (phenolic and volatile organic compounds) significantly changed during the ripening process for all of the studied cultivars. As for phenolic compounds, flavanols and hydroxybenzoic acid derivatives comprised between 87 and 95% of the total phenolic compound content in unripe green fruit. In contrast, anthocyanins and hydroxycinnamic acid derivatives comprised between 64 and 77% of the total phenolic compound content in overripe fruit, except in the fruit of the cultivar 'CIVN766'. When it comes to the aroma profile, the content of aldehydes decreased by 24-49% as the fruit ripened, and the accumulation of esters increased. Our study also shows that the ripening process differs among cultivars, and it is therefore necessary to define ripening indicators separately for each cultivar.

Variability in 'Capri' Everbearing Strawberry Quality during a Harvest Season.

Strawberries are appreciated by consumers for their characteristic taste and health benefits, which enhance their demand throughout the year. Everbearing strawberries can produce fruits for a longer period and could thus meet this demand, but the fruit quality depends on environmental factors and the cultivar. This study focused on the effect of environmental conditions on the physical attributes and the composition of everbearing Capri cultivar fruit harvested from the end of June to the end of October. A positive correlation was observed between temperature and organic acid content (r = 0.87), and a positive correlation was observed between sunshine duration, anthocyanin (r = 0.87) and phenolic compound contents (r = 0.89). Additionally, the composition of sugars was affected by the environmental conditions. While strawberries harvested towards the end of October, when lower temperatures predominated, were larger in size and had a higher sugar/acid ratio, fruit harvested in the middle of August, when there were longer periods of sunshine, had higher anthocyanin and phenolic compound contents. In conclusion, strawberries with higher sugar/acid ratios are obtained when temperatures are lower, while strawberries exposed to longer periods of sunshine are richer in health-promoting compounds.

Effect of Juglone and Other Allelochemicals in Walnut Leaves on Yield, Quality and Metabolites of Snack Cucumber (Cucumis sativus L.).

The consumption of fresh vegetables has been consistently associated with numerous health benefits. However, several factors (such as allelochemicals) influence yield, quality, and metabolites, which inevitably affect the fruit quality and health benefits. The present study was conducted to investigate the yield, quality, metabolic responses, and potential toxicity of Cucumis sativus grown in juglone-containing soils. For the treatments, pure juglone (100 µM, 1 mM) and walnut leaf extracts (100 µM) in soil concentrations found in walnut orchards were used. A total of 36 phenolic compounds were identified and quantified in fruits, leaves, and roots using a mass spectrometer coupled with high-performance liquid chromatography. We concluded that juglone at a concentration of 100 µM or walnut leaf extract at the same juglone concentration does not affect the yield of C. sativus, while juglone at a concentration of 1 mM strongly affects it. In the case of juglone, juglone itself was found only in the roots of C. sativus, but not in the leaves or fruits, so C. sativus fruits are considered safe for cultivation in juglone-containing soils. However, this could prove problematic if the plants grown are tubers or root vegetables. The data suggest that juglone itself inhibits secondary metabolism in the plant, making it more susceptible to stress and pathogen attacks.

Color Variation and Secondary Metabolites' Footprint in a Taxonomic Complex of Phyteuma sp. (Campanulaceae).

In the genus Phyteuma, the taxonomic delimitation of some species is difficult since a high variability of morphological traits, such as flower color, is present, probably due to high levels of hybridization. Historic descriptions and the morphological traits used in the taxonomic keys are sometimes unclear and lead to misinterpretations. Here, a detailed analysis of flower color variability in different populations of sympatric P. spicatum, P. ovatum, and P. persicifolium constitutes a new approach to clarifying the taxonomic statuses. The numeric analysis of color, providing colorimetric variables, together with the detailed description of the metabolic profiles of populations with different flower colors, constitute a unique chemical fingerprint that identifies species and subspecies with clear markers. This study is the most complete metabolic research on genus Phyteuma, since we identified and quantified 44 phenolic compounds using HPLC-MS, comprising 14 phenolic acids, 23 flavonols and flavones, and, for the first time in the genus, 7 anthocyanins involved in flower color variability. This approach contributes to clarifying the differences between species, which is particularly relevant in taxonomic complexes such as the present, where morphology fails to clearly differentiate taxa at specific and intraspecific levels.