Search Results (74)

Salicylic acid (SA) is involved in plant defense responses to environmental stressors by modulating gene expression and specialized metabolites production, enhancing plant adaptive resilience through systemic signaling pathways. This study investigates the impact of exogenous application of SA on the metabolism of iridoids and phenolic compounds—characteristic specialized metabolites of the Nepeta species, associated with diverse biological activities. Nepetalactone (NL) is a characteristic monoterpene iridoid, while rosmarinic acid (RA) represents the most abundant phenolic compound within the genus. We explored the effects of varying SA concentrations (2 µM, 5 µM, 10 µM, and 20 µM) on iridoid and phenolic metabolism in in vitro-grown Nepeta nuda, following 7 days and 28 days of elicitation. A significant increase in trans,trans-NL content was observed after 7-day exposure to 2 µM SA, while prolonged exposure led to a decrease in its levels, particularly at higher SA concentrations. Gene expression analysis revealed that 7 days of exposure to lower concentrations of SA upregulated genes coding for NAD-dependent nepetalactol-related short-chain dehydrogenase/reductases (NEPSs), key regulatory enzymes catalyzing the final steps of NL biosynthesis. In contrast, prolonged exposure to 20 µM SA downregulated genes coding for geraniol 8-hydroxylase (NnG8H) and 8-hydroxygeraniol oxidoreductase (Nn8HGO), which resulted in reduced iridoid content. Conversely, SA treatment notably increased RA content after prolonged exposure to 20 µM SA, which is a result of the enhanced expression of all analyzed RA biosynthesis-related genes. These findings demonstrate that both concentration and duration of SA treatment are critical determinants of elicitation outcomes in N. nuda. Strategic manipulation of these parameters can redirect metabolic flux toward either iridoid or phenolic compounds production, and enhance biotechnological production of specialized metabolites in N. nuda. Full article

Several species of saprophytic filamentous fungi are able of disrupting the life cycle of certain soil-born parasites that are of veterinary and agronomy importance, offering a promising sustainable control alternative. This study consisted of designing an experimental model, using catnip (Nepeta cataria) trays to simulate a vegetated environment for evaluating the parasiticidal activity of Mucor circinelloides, Trichoderma atrobrunneum, and Duddingtonia flagrans. Fungal spores were added to treated trays before adding feces with protozoan (Eimeria spp.), and gastrointestinal nematodes (roundworms, strongyles), and untreated-control water. No differences in plant growth or vigor, regardless of fungal presence, were observed, confirming the safety of these biological agents for vegetation. In the control trays, the viability of parasites ranged from 50% to 85%. In the treated trays, the viability of Eimeria and roundworms decreased by 40–100%, and the strongyle egg counts were reduced by 74% within 15 days. It is concluded that the vegetated tray model effectively simulates field conditions and provides a reliable platform for evaluating fungal efficacy against the free-living stages of parasites, offering a versatile tool for future research on soil-borne pathogens affecting animals and plants. Full article

The effects of progressive drought stress were examined in four economically important plant species belonging to the Lamiaceae family: catnip (Nepeta cataria L.), lavender (Lavandula angustifolia Mill.), holy basil (Ocimum tenuiflorum L.), and perilla mint (Perilla frutescens (L.) Britton). Plants were grown in a controlled pot experiment under three soil water capacity levels: 70% (control), 50% (moderate stress), and 30% (severe stress), and the drought stress lasted for 30 days. The study evaluated a comprehensive set of leaf micromorphological parameters, including the density and diameter of glandular trichomes, stomatal density and size, and the thickness of the lamina, mesophyll, epidermis, cuticle, and parenchymal layers. In addition, essential oil (EO) content, total flavonoid content (TFC), and elemental composition were analyzed. Drought responses were strongly species-specific. O. tenuiflorum, P. frutescens, and N. cataria showed high sensitivity characterized by reduced biomass and thinning of leaf tissues. These changes were accompanied by typical xeromorphic adaptations, such as increased stomatal and glandular trichome density, and reduced stomatal size. L. angustifolia exhibited pronounced cuticle thickening, suggesting an effective structural mechanism to minimize water loss. Secondary metabolism also responded differently among species. In some cases, drought shifted metabolic allocation toward flavonoid accumulation at the expense of essential oils, whereas in others, moderate stress promoted the co-accumulation of both compounds. These patterns indicate distinct adaptive strategies linking anatomical plasticity with metabolic regulation. Overall, moderate drought supported adaptive responses, while severe water limitation impaired growth and metabolic production. From a practical perspective, maintaining moderate soil water availability appears critical to optimize both plant performance and the accumulation of valuable secondary metabolites in Lamiaceae species. Full article

The reliance on synthetic repellents such as N,N-diethyl-meta-toluamide (DEET) has raised health and environmental concerns, prompting the search for safer, plant-based alternatives. Catnip (Nepeta cataria L.), a rich source of iridoid monoterpenes, particularly nepetalactones, known for strong insect-repellent activity. However, their efficient extraction and molecular mechanisms in insect inhibition remains challenging. This study examined the chemical composition, protein–ligand interactions, and safety profiles of nepetalactones in comparison with DEET, with particular focus on mosquito odorant-binding proteins (OBPs) from Anopheles gambiae (AgamOBP), Culex quinquefasciatus (CquiOBP), and Aedes aegypti (AaegOBP). GC–MS/MS analysis identified nepetalactone isomers as the predominant constituents in catnip extracts obtained via steam distillation and olive oil extraction from dried leaves. Molecular docking results indicated that cis,cis-, cis,trans-, and nepetalactone isomers exhibited higher binding affinities toward the target OBPs than DEET. Furthermore, molecular dynamics simulations confirmed that all nepetalactone–OBP complexes exhibited stable conformations characterized by low average RMSD values and persistent hydrogen bond formation. Notably, cis,trans-NL–AaegOBP, NL–AaegOBP, and cis,cis-NL–AgamOBP complexes displayed lower binding free energies (ΔG_MM-PBSA) compared to DEET. These findings suggest that nepetalactones stabilize OBP–ligand interactions while inducing subtle conformational flexibility, potentially disrupting mosquito odorant recognition in a manner distinct from DEET. ADMET predictions indicated that nepetalactones exhibit favorable absorption, distribution, and safety profiles with reduced predicted toxicity compared to DEET. Collectively, these results establish nepetalactones as promising candidates for the development of effective, safe, and sustainable plant-based repellents. Full article

Dilovasi district of Kocaeli is one of the largest industrial regions, and due to its high production capacity and industrial waste, the soil heavy metal levels in this region are exceptionally high. Consequently, this study focuses on essential elements (B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Zn) and non-essential elements that are considered toxic to humans (Al, Cd, Pb), covering a total of thirteen elements. Accordingly, this study aims to highlight the degree of pollution in a Turkish Organized Industrial Zone located in the Dilovasi district of Kocaeli by quantifying the concentrations of the aforementioned elements in Calamintha nepeta subsp. glandulosa plants and soil samples, and by assessing their potential implications for human health. Significant accumulation of heavy metals in both soils and plant parts suggests that metal contamination, especially that of Fe (up to 1009.2 mg kg⁻¹), is a matter of great concern in the Dilovasi district. The results revealed that the concentrations (mg kg⁻¹) of Cr (23.0 ± 0.1), Fe (1292.5 ± 5.6), Pb (36.9 ± 0.1), Zn (151.2 ± 0.8), and Cd (3.6 ± 0.1) were considerably higher. However, the concentrations of Cu, Mn, and Ni were found to be within the permissible limits in accordance with the American Herbal Products Association and the World Health Organization referenced guideline values. Furthermore, heavy metal concentrations in C. nepeta subsp. glandulosa were generally higher in areas characterized by elevated soil metal levels, indicating a clear correspondence between soil contamination and plant metal content. Based on these findings, C. nepeta subsp. glandulosa, a plant with culinary and medicinal value, can be considered a useful bioindicator for assessing local heavy metal contamination. Full article

Background: Recently various plants have attracted considerable scientific interest as potential therapeutic alternatives to known drugs used in anti-inflammatory therapy. Therefore, we have investigated the possible anti-inflammatory and analgesic effects of aqueous extracts from flowers of the medical plant Nepeta nuda ssp. nuda L. (naked catmint) in a model of acute peripheral inflammation induced by intraplantar injection of λ-carrageenan in the hind paw of Long Evans rats. Methods: Two routes of N. nuda extract application were used: locally by intraplantar injections at dosages of 2.5 mg/kg and 25 mg/kg and systemically by intraperitoneal administration at dosages of 50 mg/kg and 200 mg/kg, respectively. Paw volume was measured prior to the carrageenan application and 1, 2, 3, and 4 h after carrageenan injection. Spontaneous locomotor activity of the rats was assessed 3 h after carrageenan injection, corresponding to the peak of acute paw inflammation. Results: Local application of the higher N. nuda dose led to a marked reduction in inflammatory paw edema at the 4th hour after carrageenan injection, comparable to the effect of the positive control diclofenac sodium. Interestingly, a similar anti-inflammatory effect was observed at the 1st hour when both extract doses were administered intraperitoneally. Only the higher intraplantar dose of N. nuda extract significantly enhanced the vertical activity in comparison to the group treated with carrageenan alone. Conclusions: Our data indicate that the aqueous N. nuda extract possesses potent anti-inflammatory effects following both local and systemic administration in rats. Furthermore, when administered locally the extract exerts significant analgesic activity in inflammatory pain. Full article

The development of plant-based synbiotic beverages is gaining increasing attention as consumers seek sustainable, functional alternatives to dairy products. This preliminary study investigated the fortification of tibicos (water kefir) with lemon catnip (Nepeta cataria var. citriodora) hydrolate, an aromatic distillation byproduct rich in bioactive terpenoids. After 72 h-fermentation of tibicos, physicochemical, microbiological, health-promoting and sensory parameters were evaluated. Both control and fortified beverages exhibited typical fermentation kinetics, including a decrease in pH, reduction of soluble solids, and accumulation of organic acids. Lactic acid bacteria count remained stable, while yeast proliferation was slightly reduced in the hydrolate-fortified sample, consistent with the known yeast-sensitive nature of certain hydrolate-derived terpenoids. Importantly, hydrolate fortification significantly enhanced antioxidant capacity (DPPH: +34%; ABTS: +39%; RP: +38%). Enzyme-inhibitory activities also increased significantly in the hydrolate-fortified samples (α-Amylase and α-Glucosidase inhibition rates increased by 9% and 11%, respectively). ACE inhibition similarly increased from 32% to 44%, indicating an enhanced antihypertensive potential. HMG-CoA reductase inhibition increased from 31% to 42%, showing improved hypolipidemic activity. Sensory evaluation indicated improved sensory acceptability, imparting citrus–floral notes that balanced the acidic profile of tibicos. These findings highlight the potential of valorizing lemon catnip hydrolate as a functional fortifier in non-dairy synbiotic beverages. Full article

Shoot cultures of Nepeta curviflora were used to test the effect of 6-benzylaminopurine (BAP) and riboside 6-benzylaminopurine (r-BAP) on the growth and production of phenolic compounds. The best multiplication was achieved on agar Murashige and Skoog medium (MS) with r-BAP (1.5 mg/L), where 74% of explants produced about eight axillary shoots. The fresh weight (FW) was about 0.6 g/tube (24 g/L) and the dry weight (DW) was about 0.04 g/tube (2 g/L). To scale up the culture, the shoot culture was grown for the first time in a nutrient sprinkle bioreactor. After 4 weeks of culture, the multiplication rate (8.13) was higher than that observed in glass tubes (8.03). The fresh biomass was 113.2 g/bioreactor (75.5 g/L) and the dry mass was 14 g/bioreactor (9.3 g/L). Extracts from obtained plant material were analyzed by the UPLC/DAD/qTOF-MS technique. A total of 32 phenolic compounds were identified and quantified. The total content of compounds ranged from 600 to 1400 mg/100 g of dry weight (DW), depending on the culture conditions. In the profile of shoot cultures, rosmarinic acid was dominant, whereas prolithospermic acid was mostly noted in extract from aerial parts of the plant obtained from the field. Full article

Light quality and duration profoundly influence the growth and productivity of plant species. This study investigated the effects of a blue–red LED light combination, known to induce flowering, on the physiological state and content of biologically active substances in catmint (Nepeta nuda L.) grown under controlled in vitro conditions. White light (W) was used as a control and compared with two blue–red intensities: BR (high-intensity blue–red light) and BRS (low-intensity blue–red light or “BR with shadow”). BR-treated plants showed increased leaf area, mesophyll thickness, biomass and starch content but reduced levels of plastid pigments. BR also modified the oxidative state of plants by inducing lipid peroxidation while simultaneously activating ROS scavenging mechanisms and enhancing phenolic antioxidants. Interestingly, BR decreased the accumulation of the Nepeta sp.-specific iridoid, nepetalactone. These effects appear to be regulated by the phytohormones auxin, abscisic acid and jasmonates. BRS treatment produced effects similar to the W control but led to increased plant height and reduced leaf area and thickness. Both BR and BRS regimes induced the accumulation of proteins and amino acids. We conclude that blue–red light can enhance the survival capacity of micropropagated N. nuda during subsequent soil adaptation, suggesting that similar light pre-treatment could improve plant performance under stress conditions. Full article

Lemon catnip (Nepeta cataria var. citriodora) is an underutilized aromatic and medicinal plant known for its high essential oil yield and distinctive lemon-like scent, and is widely used in the pharmaceutical, cosmetic, food, and biopesticide industries. Unlike typical catnip, it lacks nepetalactones and is rich in terpene alcohols, such as nerol and geraniol, making it a promising substitute for lemon balm. Despite its diverse applications, little attention has been paid to the valorization of byproducts from essential oil distillation, such as hydrolates and their secondary recovery oils. This study aimed to thoroughly analyze the volatile compound profiles of the essential oil from Lemon catnip and the recovery oil derived from its hydrolate over three consecutive growing seasons, with particular emphasis on how temperature and precipitation influence the major volatile constituents. The essential oil was obtained via semi-industrial steam distillation, producing hydrolate as a byproduct, which was then further processed using a Likens–Nickerson apparatus to extract the recovery oil, also known as secondary oil. Both essential and recovery oils were predominantly composed of terpene alcohols, with nerol (47.5–52.3% in essential oils; 43.5–54.3% in recovery oils) and geraniol (25.2–27.9% in essential oils; 29.4–32.6% in recovery oils) as the primary components. While sesquiterpene hydrocarbons were mostly confined to the essential oil, the recovery oil was distinguished by a higher presence of monooxygenated and more hydrophilic terpenes. Over the three-year period, elevated temperatures led to increased levels of geraniol, geranial, neral, and citronellal in both oils, whereas cooler conditions favored the accumulation of nerol and linalool, especially in the recovery oils. Higher precipitation was associated with elevated concentrations of nerol and linalool but decreased levels of geraniol, geranial, and neral, possibly due to dilution or degradation processes. Full article

A plant species in a community often grows with some other plant species. While many studies have assessed interspecific interactions between two target plant species, few have considered the impacts of the other plant species (e.g., the third, fourth, and fifth plant species) on these interactions. To assess the impacts, we grew one seedling of each of the five herbaceous plant species that are common in China (Cynodon dactylon, Plantago asiatica, Taraxacum mongolicum, Nepeta cataria, and Leonurus japonicus) alone (no competition) or with one seedling of one, two, three, or four of the other species. The presence of a neighbor plant generally reduced the growth of the target species, suggesting that the interspecific relationships were mostly competitive. The presence of other neighbor species (the third, fourth, and fifth species) could alter the interspecific interactions between two target species, but such effects varied depending on both the identity of the target species and the identity of the other species. Additionally, the effects of the third species depended little on the presence of the fourth and fifth species. We conclude that interspecific interactions between two plant species are commonly regulated by the presence of other species, facilitating species coexistence. However, our findings do not support the idea that the impacts of the fourth and fifth species on interactions among three plant species are common. This study highlights the complex interactions among multiple plant species within a community and also the importance of including these high-order interactions when modelling community dynamics and species coexistence. Full article

During field surveys carried out in 2021 at two farms in Lombardy (North Italy), leaf samples were collected from 113 plants (both symptomatic and asymptomatic) belonging to 18 medicinal and aromatic species. Amplification and nucleotide sequence analyses of the 16S rRNA gene revealed the presence of ‘Candidatus Phytoplasma solani’ (subgroup 16SrXII-A) in 69 plants (61% infection rate) belonging to 14 of the 18 examined species. Among the 14 infected species, only Nepeta cataria L. exhibited symptoms including leaf and stem reddening. Molecular typing analyses showed that ‘Ca. P. solani’ strains identified in this study constitute a genetically homogeneous population, carrying the stamp gene sequence variant St5 and the new vmp1 gene sequence variant Vm93. Phylogenetic analyses showed that ‘Ca. P. solani’ strain St5/Vm93 belongs to the cluster b-II, associated with the bindweed-related pathosystem. In silico-translated Vmp1 protein sequence alignment suggested that ‘Ca. P. solani’ strain St5/Vm93 could be generated by recombination events between ‘Ca. P. solani’ strains co-infecting the same host. The results suggested future research investigating the diffusion and the ecology of ‘Ca. P. solani’ strain St5/Vm93 in agroecosystems (including other crops), and its effect on the composition of biologically active compounds in aromatic and medicinal plants. Full article

Many specialized metabolites found in plants have significant potential for developing environmentally friendly weed management solutions. This review focuses on the phytotoxic effects of volatile terpenes and phenolic compounds, particularly nepetalactone, an iridoid monoterpenoid from Nepeta species, and phloretin, a dihydrochalcone predominantly found in the genus Malus. We highlight current findings on their herbicidal effects, including morphological, physiological, and biochemical responses in target plants. These results underscore their potential for developing sustainable herbicides that could control weeds with minimal environmental impact. We also discuss their soil persistence and methods to enhance their solubility, chemical stability, and bioavailability. Additionally, the possible effects on non-target organisms, such as pollinators, non-pollinating insects, and soil microbiota, are considered. However, further research and a deeper understanding of their long-term ecological impact, along with a resistance development risk assessment, is essential for the potential development of bioherbicides that could be applied in sustainable weed management practices. Full article

Gastrointestinal nematodes (GINs) inflict significant economic losses on sheep and goat farming globally due to reduced productivity and the development of anthelmintic resistance. Sustainable control strategies are urgently needed including the exploration of medicinal plants as safer alternatives to chemical anthelmintics. This genus of plants is used for anti-inflammatory, antioxidant, and antimicrobial activities. In this study, we aimed to evaluate the anthelmintic activities of Nepeta racemosa Lam. MeOH extract, n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc), n-buthanol (n-BuOH) and aqueous (H₂O) subextracts, and quantify rosmarinic acid in the active extract by the HPLC method, and perform in silico molecular docking studies of rosmarinic acid to examine its binding interactions with tubulin. The anthelmintic activity of the plant extracts on gastrointestinal nematode eggs and larvae (L3) of the sheep was assessed using in vitro test methods such as the egg hatch assay and larval motility assay, conducted over a 24 h period (1, 2, 3, 4, 6, 8, 24). All extracts exhibited 100% effectiveness in the egg hatch inhibition assay, regardless of concentration (50–1.5625 mg/mL). The EtOAc subextract shows the highest effectiveness at 79.66%, followed by the MeOH extract at 74.00%, water at 64.00%, n-hexane at 67.00%, and DCM at 61.00%, and the lowest effectiveness is observed with n-BuOH at 51.66% in the larval motility assay. The major compound of EtOAc extract, the most active extract of N. racemosa, was determined as rosmarinic acid and its amount in the extract was determined as 14.50 mg/100 mg dry extract. The amount of rosmarinic acid in the MeOH extract was found to be 0.21 mg/100 mg dry extract. n-Hexane, DCM, n-BuOH, and H₂O extracts’ rosmarinic acid content was lower than the LOQ value. As tubulin plays an important role in the mechanism of anthelmintics, the major compound of the most active extract (NR-EtOAc) rosmarinic acid was docked onto the colchicine-binding site of the tubulin (5OV7) protein. Rosmarinic acid showed a similar activity spectrum to the anthelmintic drug albendazole. The discovery of low-cost and low-toxicity anthelmintic compounds is very important. Full article

Despite significant efforts, cancer remains the second leading cause of mortality worldwide. The medicinal plant Nepeta nuda L. represents a valuable source of biologically active compounds with pharmacological activities including antioxidant, anti-inflammatory, antimicrobial, and antiviral. This study aimed to assess the antiproliferative potential and mechanisms of action of aqueous extract from the leaves of wild-grown N. nuda. Cancer cell lines, MDA-MB-231, MCF7 (breast), HT29, Colon 26 (colon), and HepG2 (liver cancer), and a non-cancerous skin cell line, BJ, were assessed for antiproliferative activity by MTT assay and observation of cell morphological alterations. The cancer cell line that was most sensitive to the extract was further studied for apoptotic alterations by Annexin V/propidium iodide staining, colony-forming assay, and qRT-PCR analysis. The results revealed that the plant extract inhibited the proliferation of all investigated cancer cell lines with the strongest cytostatic effect on Colon 26 cells with a half maximal inhibitory concentration (IC₅₀) value of 380.2 μg/mL and a selectivity index (SI) of 3.5. The extract significantly inhibited the ability of cells to form colonies, exhibited considerable proapoptotic potential involving the participation of the CASP8 gene, and increased the expression levels of ATG3 and the BECN1 gene, which suggests a role of autophagic cell death in the antitumor action. Full article