Chlorogenic acid is one of the most prominent bioactive phenolic acids with great pharmacological, cosmetic and nutritional value. The potential of Berula erecta in tissue culture was investigated for the production of chlorogenic acid and its elicitation combined with light of different wavelengths and low temperature. The content of chlorogenic acid in the samples was determined by HPLC-UV, while the content of total phenolic compounds and the antioxidant activity of their ethanol extracts were evaluated spectrophotometrically. The highest fresh and dry biomasses were obtained in plants grown at 23 °C. This is the first study in which chlorogenic acid has been identified and quantified in Berula erecta. The highest chlorogenic acid content was 4.049 mg/g DW. It was determined in a culture grown for 28 days after the beginning of the experiment at 12 °C and under blue light. The latter also contained the highest content of total phenolic compounds, and its extracts showed the highest antioxidant activity. Berula erecta could, potentially, be suitable for the in vitro production of chlorogenic acid, although many other studies should be conducted before implementation on an industrial scale.

Mulberries are the “essence of the past”, the so-called Proust effect, for the inhabitants of the sericultural regions who enthusiastically remember feeding silkworms with mulberry leaves and picking the different coloured fruits that were their favourite sweets in childhood. To determine the chemistry behind the colour and taste of mulberry soroses, the main metabolites of the local and introduced varieties were studied. The soroses were classified into five different colour types and the size parameters were determined. The main sugars identified were glucose and fructose, while the predominant organic acids were citric and malic acids, which were highest in the darker varieties, and fumaric and tartaric acids, which were highest in the lighter varieties. A total of 42 phenolic compounds were identified. The predominant phenolic acid was chlorogenic acid, followed by other caffeoylquinic acids and coumaroylquinic acids. The predominant anthocyanins were cyanidin-3-glucoside and cyanidin-3-rutinoside. According to PCA analysis, the colour types showed a clear chemotype character. The sweet taste of the yellowish-white soroses was defined by 49% fructose, followed by 45% glucose and 6% organic acids. The sour character of the black genotypes was characterised by a lower sugar and higher (11%) organic acid content. The colour- and species-dependent effect was observed in the proportion of caffeoylquinic acids and quercetin glycosides, which decreased with increasing colour intensity from 60% of the total to 7%, and from 17% to 1%, respectively. An upward trend was observed for flavanols (5% to 29%) and anthocyanins, which accounted for 62% of the total phenolics in black varieties. This article gives an insight into the metabolite composition of mulberry soroses as the sweets of choice between light and sweet and dark and sour.

Phenolic compounds are strong antioxidant and antibacterial agents with great pharmacological, medicinal, nutritional, and industrial value. The potential of Morus nigra in stem node culture was investigated for the production of phenolic compounds and their elicitation with CuSO₄. Individual phenolic compounds in the samples were identified and quantified by using HPLC-PDA and HPLC-MS methods, while the content of total phenolic compounds, the content of total flavonoids, and the antioxidant activity of methanolic extracts were evaluated spectrophotometrically. The highest fresh and dry weights were obtained in plantlets treated with 0.5 mM CuSO₄ for 42 days. The highest total phenolic content, total flavonoid content, and antioxidant activity of the extracts were determined in stem node cultures treated with 3 mM CuSO₄ for 42 days. Under the latter conditions, the predominant representatives of the caffeoylquinic acids, p-coumaric acid derivatives, kaempferol derivatives, and quercetin derivatives also achieved the highest content. The most abundant phenolic compound in all samples was the chlorogenic acid. The nodal culture of M. nigra elicited with CuSO₄ could potentially be used for the industrial production of phenolic compounds, especially caffeoylquinic acids. Moreover, considering the biochemical response to CuSO₄ treatment and the ability to tolerate and accumulate copper, the potential application of M. nigra in phytoremediation is also highlighted.

Mulberry (Morus sp.) trees, traditionally cultivated for their leaves used in sericulture, have recently gained recognition for their adaptability and valuable ecosystem services. The biochemical composition of mulberry leaves varies both qualitatively and quantitatively, depending on genotype, environmental conditions, and cultivation practices. This study aimed to (1) identify differences in old local white (M. alba L.) and black mulberry (M. nigra L.) leaves, (2) perform a chemotype analysis of monitored local varieties, and (3) evaluate the influence of selected bioclimatic factors and pruning practices on the biochemical composition of leaves of white mulberry trees across Slovenian mesoregions. Black mulberry exhibited a higher phenolic content, particularly caffeoylquinic acid derivatives (16.05 mg/g dry weight (DW)), while white mulberry contained more quercetin glycosides (6.04 mg/g DW). Ward’s clustering identified three chemotypes, two of which had elevated protein and hydroxycinnamic acid levels, making them particularly suitable for silkworm feeding. Considering pruning practices of white mulberries, we determined significantly increased protein contents in yearly pruned trees (187.24 mg/g DW). Principal component analysis revealed interactions between bioclimatic, morphological, and biochemical factors, distinctly separating mulberries from the Sub-Mediterranean and Sub-Pannonian macroregions. White mulberries from Sub-Pannonian regions accumulated more caffeoylquinic acids in leaves under lower precipitation and total insolation, while those from Sub-Mediterranean regions exhibited higher kaempferol derivatives due to photo-thermal stress. These findings highlight the influence of climate and pruning on mulberry biochemical diversity and adaptation.

Slug herbivory is an important but poorly explored driver of plant defence and belowground multitrophic interactions. This study examined how aboveground feeding by Arion vulgaris and Deroceras reticulatum affects oxidative status, photosynthetic pigments, and volatile organic compound (VOC) emissions in cabbage (Brassica oleracea L. var. capitata), and whether these changes influence slug-parasitic nematodes. Slug feeding induced strong oxidative stress in leaves and roots, reflected by depletion of total ascorbate and glutathione contents and increased proportions of their oxidized forms, indicating a systemic redox imbalance. Photosynthetic pigments were also markedly affected, characterized by decreased chlorophylls and carotenoids and activation of the xanthophyll cycle towards more zeaxanthin, particularly in plants attacked by D. reticulatum. Headspace SPME–GC–MS analysis revealed tissue-specific, herbivory-induced shifts in VOC profiles. Based on these changes, three VOCs—3-phenylpropionitrile, allyl isothiocyanate, and 2-hexenal—were selected for chemotaxis assays. Behavioural experiments showed that VOC identity and nematode species markedly influenced motility and chemotactic responses. Phasmarhabditis papillosa exhibited the strongest attraction to 3-phenylpropionitrile, whereas allyl isothiocyanate acted as a weak repellent to P. papillosa, Oscheius myriophilus, and Oscheius onirici. In contrast, 2-hexenal elicited no consistent directional response. These results demonstrate that slug herbivory alters cabbage metabolism and volatile signalling, shaping species-specific nematode behaviour and highlighting its potential for sustainable slug management.

Copper (Cu) is an essential plant micronutrient, but in excessive amounts it becomes phytotoxic, making Cu contamination of agricultural soils an important environmental concern. Because Cu tolerance mechanisms are complex and often genotype-specific, there is growing interest in multipurpose crops capable of thriving under metal stress. Mulberry is one of such species, which enables the combination of diverse agricultural uses with notable tolerance to heavy metals. In the present study, the tolerance to Cu-induced stress of five varieties belonging to Morus alba and M. indica was assessed in a pot experiment, in which the trees were watered with a CuSO₄ solution that increased the soil Cu concentration to 150 mg kg⁻¹, while the plants in the control group were watered with the same volume of tap water. In leaves sampled on days 0, 3, 7, and 21 after CuSO₄ treatment, Cu content was analyzed by AAS; ascorbate, dehydroascorbate, thiols, oxidized thiols and xanthophyll pigments were analyzed by HPLC; and total phenolic content and photosynthetic pigment content were determined spectrophotometrically. The effect of CuSO₄ treatment on the maximum quantum yield of photosystem II was analyzed by measuring the chlorophyll fluorescence of leaves on day 21 after CuSO₄ treatment. The results showed a species-specific response to Cu-induced stress. Leaves of M. alba varieties exhibited a more pronounced increase in Cu content, higher antioxidant levels, more efficient redox regulation, a smaller decline in photosynthetic pigment contents and photosynthetic efficiency, resulting in more effective photoprotection through the xanthophyll cycle when compared to M. indica varieties under the conditions of this experiment. In particular, the varieties ‘Florio’ and ‘Giazzola’ exhibited high Cu tolerance and therefore show potential for cultivation in Cu-contaminated soils.