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.

Impact of Two Brown Seaweed (Ascophyllum nodosum L.) Biostimulants on the Quantity and Quality of Yield in Cucumber (Cucumis sativus L.).

Algal biostimulants are increasingly integral to vegetable cultivation due to their capacity to boost yield, alleviate abiotic and biotic stress, and enhance overall crop quality. This study evaluated the impact of two commercially available algal-based biostimulants on cucumber (Cucumis sativus L.), examining their effects on yield, number of fruits, dry weight, color, flesh thickness, skin thickness, plastid pigments, and tocopherol content. Both biostimulant treatments resulted in a roughly 13% decrease in yield and fruit number compared to the control treatment. Notably, the biostimulants positively influenced the fruit brightness parameter (L*), leading to darker fruits. Fitostim® algal biostimulant exhibited a positive effect on dry weight during the initial harvest. The predominant pigments were chlorophyll a and chlorophyll b (constituting 80% of all analyzed pigments), and the most abundant tocopherol was α-tocopherol, comprising 80% to 90% of tocopherols. Skin tissues contained significantly higher levels of pigments and tocopherols compared to flesh. Both biostimulants caused a notable decrease in total tocopherol content in the skin at the first harvest, with reductions of 19.91 mg/kg DW for Phylgreen® and 9.43 mg/kg DW for Fitostim® algae. The study underscores the variable efficacy of biostimulants, emphasizing their dependence on the specific biostimulant type and fruit part. The application of biostimulants has the potential to substantially enhance the internal quality of cucumbers, particularly in terms of plastid pigments and tocopherols, offering potential health benefits for consumers.

HPLC-Mass spectrometry analysis of phenolics comparing traditional bilberry and blueberry liqueurs.

The purpose of this study was to investigate the differences between the phenolics compositions of bilberry and blueberry liqueurs, to determine whether these are comparable. Both bilberry and blueberry liqueurs have the same name on the market, however they differ in phenolic composition and content. A total of 43 compounds were identified, 36 in the bilberry liqueur, and 21 in the blueberry liqueur. High performance liquid chromatography coupled with mass spectrometry (HPLC-MS) was used to identify and quantify these compounds, where they were fragmented to the MS4 fragments. Anthocyanins were the major phenolics group detected in the bilberry liqueurs, but only the second most abundant phenolics group in the blueberry liqueurs. The most abundant phenolics group in the blueberry liqueurs was hydroxycinnamic acids. The lowest content of individual phenolic compounds was for blueberry liqueur made from whole fruit. This study will provide valuable data to consumers in their choice of a more expensive bilberry liqueur or a cheaper blueberry liqueur.

Identification and Quantification of the Major Phenolic Constituents in Castanea sativa and Commercial Interspecific Hybrids (C. sativa x C. crenata) Chestnuts Using HPLC-MS/MS.

Due to the lack of studies on chestnut metabolites, this study was conducted to identify and quantify the major phenolic constituents in chestnuts. Data were compared with the three most commonly grown interspecific hybrids of C. sativa and C. crenata ('Bouche de Betizac', 'Marsol', and 'Maraval') and three "native" accessions of C. sativa. High-performance liquid chromatography coupled with mass spectrometry was used to identify and quantify these compounds. Four dicarboxylic acid derivatives, five hydroxybenzoic acids, nine hydroxycinnamic acids, and three flavanols were identified and quantified, most of them for the first time. Hydroxybenzoic acids were the major phenolic compounds in all chestnut cultivars/accessions, followed by flavanols, dicarboxylic acid derivatives, and hydroxycinnamic acids. Of all the compounds studied, the (epi)catechin dimer was the most abundant in chestnut. The assumption that cultivars from commercial hybrids have a better and different metabolic profile than "native" accessions was refuted.

Effect of Different Walnut and Hazelnut Leaf Compost Treatments on Yield and Phenolic Composition of Lactuca sativa L.

The use of compost made from the leaves of Juglans regia has long been controversial because of its inhibitory effect due to the presence of juglone. Therefore, the aim of our study was to replicate the typical habits of farmers and gardeners, where the dried leaves are collected at the end of the season and placed in a composter. Then, the effects of the different treatments on the yield of the plant (lettuce), secondary metabolism, and possible toxicity of the compost of the grown plant were evaluated. The lowest yield of lettuce was obtained in soil with composted walnut and hazelnut leaves, while the highest yield was recorded in in soil with compost control, soil with composted walnut leaves and grass with the addition of composting agent and soil with composted walnut leaves with addition of composting agent. Some allelochemicals were still present in the compost but at such low levels that they did not affect yield. We suggest that dry walnut leaves and cut grass can be used for composting, while dry hazelnut leaves still contain some allelochemicals after two years that significantly inhibit plant growth and thus yield, so we would not recommend their use for composting.

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.

Characterization and Quantification of Capsaicinoids and Phenolic Compounds in Two Types of Chili Olive Oils, Using HPLC/MS.

Chili olive oil is a popular addition to various foods in many countries. In a detailed study, the content of phenols and capsaicinoids in chili olive oil was determined using chili flakes and whole chilies. A total of 99.8% of the phenols in chili olive oil were secoiridoids, with elenolic acid, oleuropein aglycones, and ligostride aglycones being the most abundant. Chili olive oil with chili flakes contained higher levels of capsaicinoids (+21.6%) compared to whole chili olive oil. Capsaicin and dihydrocapsaicin accounted for about 95% of all capsaicinoids in the chili olive oil. The extraction rate of dry "Cayenne" chili was 7.1% in whole chili olive oil and 9% in chili olive oil with flakes, confirming that chili flakes are better extracted in olive oil. With the determination of 29 individual phenols and five individual capsaicinoids, the study provided a detailed insight into the secondary metabolites of chili olive oil and confirmed that it is a health source.

Biostimulatory Effects of Amino Acids on Phenylalanine Ammonia Lyase, Capsaicin Synthase, and Peroxidase Activities in Capsicum baccatum L.

Biostimulants are widely used in agriculture because they can improve fruit quality and quantity. Less is known about how biostimulants act over time in plants, in our case peppers, and how they affect the enzyme activity of important enzymes for capsaicinoid synthesis. The biostimulatory effects of amino acids on the activities of phenylalanine ammonia lyase (PAL), capsaicin synthase (CS), and peroxidase (POX) were investigated in the pericarp and placenta of the chili pepper Capsicum baccatum L. cv. "Bishop Crown" over 72 h of application. The PAL and CS activities significantly increased in the placenta after 1 h of biostimulant application, with significant increases of 130% and 16%, respectively. The POX activity remained unchanged over the full 72 h in the placenta but significantly increased after 48 h in the pericarp (+53%). Total capsaicinoids increased in the first hour of biostimulant application, by 4.30 g/kg FW in the placenta (19%) and by 0.94 g/kg FW in the pericarp (+56%). Biostimulant application also increased total and individual capsaicinoids after 48 h in the chili placenta and pericarp. With improved methods for enzymatic determination, we gained new insights into the responses of chilies to biostimulant amino acids.

Salt Stress Differentially Affects the Primary and Secondary Metabolism of Peppers (Capsicum annuum L.) According to the Genotype, Fruit Part, and Salinity Level.

A total of four Capsicum annuum L. genotypes ('Caro F1', 'Berenyi F1', 'Somborka' and 'Novosadka') were exposed to two intensities of salt stress. We observed a significant decrease in the sugar content in all salt stressed treatments, except for the sucrose content of the pericarp of the 'Caro F1' cultivar. Salt stress had a largely negative effect on the total and individual organic acid content, although the effect differed among cultivars. Using high performance liquid chromatography coupled with a mass spectrometer, most phenolics were identified in the pericarp (18), followed by the placenta (7) and seeds (8). Treatment with 40 mM NaCl caused the highest increase in individual phenols, followed by treatment with 20 mM NaCl. The cultivar 'Berenyi F1' was less affected by salt stress treatment than the other three cultivars in terms of content of individual and total phenols. Salt stress increased the content of capsaicinoids in all the cultivars. The pericarp of the cultivar 'Novosadka' showed 17.5 and 50 times higher total capsaicinoid content than the control in the 20 mM and 40 mM NaCl, respectively. With the results of several metabolite groups, we confirmed that the reaction and metabolic content to salt stress within the genus Capsicum is genotype-, fruit part-, and salinity level-dependent.

Time-Dependent Degradation of Naphthoquinones and Phenolic Compounds in Walnut Husks.

The aim of the present study was to investigate how individual phenolic compounds and phenolic groups in walnut husk gratings (e.g., naphthoquinones, flavanols, flavonols, hydroxycinnamic acids) are oxidized over time, with a particular focus on the juglone synthase pathway. Walnut husk gratings were prepared and left under 'degradation' conditions (exposure to the air, room temperature) at increasing times. Following methanol extraction of these husk gratings, the HPLC profile of methanolic extract of husk gratings exhibited twenty-six compounds over time, then hydrojuglone glucoside, α-hydrojuglone, and juglone were detailed by HPLC-mass spectrometry. Initially (0-20 min), the content of hydrojuglone glucoside in the husk gratings decreased by 40.4%, while the content of α-hydrojuglone increased by 20.0%, and then decreased. After an initial delay (0-20 min), juglone increased by 47.9% from 20 to 40 min, and then decreased. This initially confirmed that hydrojuglone glucoside and α-hydrojuglone could be considered as precursors of juglone. Different phenolic groups showed different degradation processes, although they all reached their highest content after 40 min. This might arise from degradation of the phenols, increased free phenols, or activation of the plant defense mechanism due to damage to the tissue, similar to the effects of stress or a pathogen attack. Although it has been reported that the phenolic compounds decrease when food is processed or damaged, they showed increases, which were not indefinite, but time dependent. As phenolic compounds are considered highly beneficial to human health, increases upon processing indicate the need for further investigations into healthier food preparation processes. This is the first study on the degradation pathways of juglone, using a mass spectrometer, in which we suggest that hydrojuglone glucoside and α-hydrojuglone are indeed the precursors of juglone. However, it is possible that there are other degradation pathways of hydrojuglone glucoside, since less juglone is synthesized than expected.

Influence of intra and inter species variation in chilies (Capsicum spp.) on metabolite composition of three fruit segments.

Twenty-one different cultivars from four different species were examined. The highest dry weight was present in seeds (between 35 and 50%) and the average water content was 60%. Placenta and pericarp contained on average 86% water. Total sugars variation between species was 60%. The most concentrated in the various cultivar pericarps were ascorbic acid ranging from 368.1 to 2105.6 mg/100 g DW and citric acid ranging from 1464.3 to 9479.9 mg/100 g DW. Total phenolic content ranged from 2599.1 mg/100 DW in 'Chilli AS- Rot' to 7766.7 mg/100 g DW in 'Carolina Reaper'. The placenta had 23.5 times higher phenolic content than seeds. C. chinense and C. chinense × C. frutescens had 3.5 to 5 times higher capsaicinoid content compared to C. annuum and C. baccatum, with 'Carolina Reaper' having the highest content at 7334.3 mg/100 g DW and 'Chilli AS- Rot' the lowest (318.7 mg/100 g DW).

Metabolic Variation among Fruits of Different Chili Cultivars (Capsicum spp.) Using HPLC/MS.

Chilies are widely cultivated for their rich metabolic content, especially capsaicinoids. In our study, we determined individual sugars, organic acids, capsaicinoids, and total phenolic content in pericarp, placenta, and seeds of Capsicum annuum L., Capsicum chinense Jacq. and Capsicum baccatum L. by HPLC/MS. Dry weight varied in the cultivar 'Cayenne', with the first fruit having the lowest dry weight, with 4.14 g. The total sugar content and organic acid content did not vary among the fruits of all three cultivars. The cultivar 'Cayenne' showed differences in total phenolic and capsaicinoid content between fruits in the placenta, with the first fruit having the highest content of total phenolics (27.85 g GAE/kg DW) and total capsaicinoids (16.15 g/kg DW). Of the three cultivars studied, the cultivar 'Habanero Orange' showed the least variability among fruits in terms of metabolites. The content of dihydrocapsaicin, nordihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin in the seeds of the second fruit was higher than that of the first fruit of the cultivar 'Bishop Crown'. The results of our study provided significant insight into the metabolomics of individual fruits of the same chili plant. We have thus increased our understanding of how certain metabolites are distributed between fruits at different levels of the same plant and different parts of the fruit. This could be further investigated when chilies are exposed to different environmental stresses.