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IntroductionThis study presents the essential oils (EOs) derived from Origanum majorana L. (Marjoram), Mentha spicata L. (Spearmint) and Ocimum basilicum L. (Basil), which are explored for their insecticidal potential against Spodoptera littoralis larvae.MethodsEOs were extracted and analyzed using gas chromatography-mass spectrometry (GC-MS), identifying 47, 37 and 27 compounds in O. majorana, M. spicata and O. basilicum , respectively.ResultsMajor constituents include terpinen-4-ol (25.47 %) and sabinene (18.3%) in O. majorana , piperitenone oxide (43.83 %) in M. spicata , and methyl (E)-cinnamate (48.69 %) in O. basilicum . Toxicity assays demonstrated significant larvicidal activity with LC50 values of 1.18 % for O. majorana , 0.43% for M. spicata , and 0.51% for O. basilicum . Furthermore, these EOs notably influenced the expression of defense-related genes in S. littoralis , with treated larvae showing an ~80% increase in PR1 , endoglucanase ( PR2 ) and chitinase gene expression compared to controls. Differential display confirmed the amplification of these regulated genes in treated insects.DiscussionThis research underscores the efficacy of EOs from O. majorana, M. spicata and O. basilicum as natural insecticides, providing valuable insights for sustainable pest management through specific gene markers.

Extraction is the first and most important step in obtaining the effective ingredients of medicinal plants. Mentha longifolia (L.) L. is of considerable economic importance as a natural raw material for the food and pharmaceutical industries. Since the effect of different extraction methods (traditional and modern methods) on the quantity, quality and antimicrobial activity of the essential oil of this plant has not been done simultaneously; the present study was designed for the first time with the aim of identifying the best extraction method in terms of these features. For this purpose, extracting the essential oil of M . longifolia with the methods of hydrodistillation with Clevenger device (HDC), steam distillation with Kaiser device (SDK), simultaneous distillation with a solvent (SDE), hydrodistillation with microwave device (HDM), pretreatment of ultrasonic waves and Clevenger (U+HDC) and supercritical fluid (SF) were performed. Chemical compounds were identified by gas chromatography coupled with mass spectrometer (GC-MS). Antimicrobial activity of essential oils against various clinical microbial strains was evaluated by agar diffusion method and determination of the minimum inhibitory concentration and minimum bactericidal concentration (MIC and MBC). The results showed that the highest and lowest yields of M . longifolia leaf essential oil belonged to HDC (1.6083%) and HDM (0.3416%). The highest number of compounds belonged to SDK essential oil and was equal to 72 compounds (with a relative percentage of 87.13%) and the lowest number of compounds was related to the SF essential oil sample (7 compounds with a relative percentage of 100%). Piperitenone (25.2–41.38%), piperitenone oxide (22.02–0%), pulegone (10.81–0%) and 1,8-cineole (5–35.0%) are the dominant and main components of M . longifolia essential oil were subjected to different extraction methods. Antimicrobial activity results showed that the lowest MIC value belonged to essential oils extracted by HDM, SDK, SDE and U+HDC methods with a value of 1000 μg/mL was observed against Gram-negative bacteria Shigella dysenteriae , which was 5 times weaker than rifampin and 7 times weaker than gentamicin. Therefore, it can be concluded that in terms of efficiency of the HDC method, in terms of the percentage of compounds of the HDM method, and in terms of microbial activity, the SDK, HDM and U+HDC methods performed better.

The present study aimed to explore the phytochemical profile, and evaluate the antioxidant, antimicrobial, and insecticidal properties, of Moroccan Mentha longifolia L. essential oil (ML-EO) using in vitro and in silico assays. Noteworthily, as chromatography (GC-MS/MS) revealed that ML-EO is majorly composed of piperitenone oxide (53.43%), caryophyllene (20.02%), and (−) germacrene D (16.53%). It possesses excellent antioxidant activity with an IC50 of 1.49 ± 0.00 for DPPH and 0.051 ± 0.06 μg/mL for ABTS. Moreover, the RP and TAC activities were 0.80 ± 0.01 μg/mL and 315.532 ± 0.00 mg EAA/g, respectively. ML-EO exhibited a potent antimicrobial effect, specifically against Pseudomonas aeruginosa. It also exhibited strong antifungal ability, especially against Candida albicans. Regarding insecticidal activity, for ML-EO, a dose of 20 µL/mL produced a complete reduction in fecundity, fertility, and emergence of adult C. maculatus with mortality rates reaching 100%. In silico results showed that the antioxidant activity is mostly attributed to α-Cadinol, the antibacterial efficiency is attributed to piperitenone oxide, and antifungal capacity is related to cis-Muurola-4(15),5-diene and piperitenone oxide. Accordingly, ML-EO has high potential to be used as an alternative for preserving food and stored grain and protecting them against microbes and insect pests in the food and pharmaceutical sectors.

A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL−1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy.

The postharvest life of most fruit, vegetables and cereals is limited by fungal proliferation. The chemical composition of Mentha piperita, M. spicata and M. suaveolens essential oils (EO), and the antifungal activity against four pathogenic and post-harvest fungi isolated from food, were herein investigated to evaluate their potential as natural food preservatives. The EO were obtained by hydrodistillation of aerial parts leaves, stems and inflorescences (except for peppermint oil, which was purchased in a specialized store) and submitted to GC-MS and GC-FID analysis. Regarding the EO composition, carvone (41.1%) and limonene (14.1%) were the major compounds in M. spicata, menthol (47.0%) and menthone (23.1%), as well as other menthol derivatives (neomenthol -3.6%- and menthofurane -3.7%-) in M. piperita, and piperitone oxide (40.2%) and piperitenone oxide (31.4%) in M. suaveolens.Botryotinia fuckeliana was the most sensitive fungus. The three studied EO inhibited growth by 92–100%. The highest dose of M. suaveolens EO, 400 µg/mL, produced 100% MGI in all the studied fungi, except Fusarium oxysporum with 94.21%. The M. suaveolens EO can be considered to develop a low-risk enviro-friendly botanical biofungicide.

Essential oils (EOs) derived from medicinal plants are gaining recognition as sustainable alternatives to synthetic fungicides in the management of plant pathogens. This study investigates the chemical composition, chromatographic profile, and antifungal of Mentha rotundifolia essential oil against Fusarium oxysporum f. sp. albedinis (Foa), the pathogen responsible for Bayoud disease in date palm. The oil was extracted through hydrodistillation and characterized using thin-layer chromatography (TLC) and gas chromatography–mass spectrometry (GC-MS), revealing multiple fractions corresponding to terpenoid constituents and 23 chemical constituents, predominantly oxygenated monoterpenes (68.51%), with piperitenone oxide as the major component (62.53%). The antifungal efficacy was evaluated against ten (10) isolates of F.o.a across seven (07) concentrations different concentrations. (0; 0.25; 0.5; 0.75; 1; 1.25; 1.5μL/mL). The results obtained show a progressive decrease in the diameters of the colonies of F.o.a isolates by increasing the doses of EOMR. The percentage of inhibition varies from 7.82 to 83.41%; However, the dose of 1.75μL/mL showed 100% inhibition for all F.o.a isolates tested. These outcomes demonstrate the potential of M. rotundifolia essential oil as a natural, environmentally friendly antifungal agent, supporting its application in sustainable management strategies for Bayoud disease in date palm.

The present study assessed the phytotoxic and cytotoxic potential of the essential oil (EO) extracted from aboveground parts of Mentha longifolia (L.) Huds. Gas chromatography–mass spectrometry revealed 39 compounds constituting 99.67% of the EO. The EO was rich in monoterpenoids (mostly oxygenated monoterpenes), which accounted for 89.28% of the oil. The major components in EO were monoterpene ketones such as piperitone oxide (53.83%) and piperitenone oxide (11.52%), followed by thymol (5.80%), and ( E )-caryophyllene (4.88%). The phytotoxic activities of EO were estimated against Cyperus rotundus , Echinochloa crus-galli , and Oryza sativa (rice) through pre- and post-emergence assays at concentrations ranging from 10 to 250 μg/ml and 0.5–5%, respectively. In pre-emergence assay, the phytotoxic effect of EO was most pronounced on C. rotundus , thereby significantly affecting percent germination, plantlet growth, and chlorophyll content. On the contrary, the impact was comparatively lesser on rice, with ~ 40% germination in response to 250 μg/ml of EO treatment. In the post-emergence assay, the spray treatment of EO caused a loss of chlorophyll and wilting in test plants, and subsequently affected the growth of plants, even leading to death in some cases. The cytotoxic activity of EO (at 2.5–50 μg/ml) was studied in meristem cells in onion ( Allium cepa L.) root tips. EO exposure to the onion roots induced various chromosomal aberrations such as chromosomal bridges, c-mitosis, stickiness, vagrant chromosomes, etc., and negatively affected the mitotic index. At 50 μg/ml, EO treatment triggered the complete death of roots. The study concludes that M. longifolia EO has phytotoxic activities due to the mito-depressive effect, along with other physiological effects on target plants. Therefore, EO of M. longifolia could be developed into a novel bioherbicide for sustainable management of weeds in agricultural systems.

The present study examined the effects of foliar spray of selenium nanoparticles (0, 10 and 20 mg/L) on the yield, phytochemicals and essential oil content and composition of pineapple mint (Mentha suaveolens Ehrh.) under salinity stress (0, 30, 60 and 90 mM NaCl). Obtained results demonstrated that severe salinity stress reduced the fresh weight (FW) and plant height (PH) by 16.40% and 19.10%, respectively compared with normal growth condition. On the other hands, under sever salinity stress relative water content (RWC) and chlorophyll index were reduced by 18.05% and 3.50%, respectively. Interestingly, selenium nanoparticles (Se-NPs; 10 mg/L) application improved the pineapple mint growth. Based on GC-FID and GC-MS analysis, 19 compounds were identified in pineapple mint essential oil. Foliar application of Se-NPs and salinity did not change the essential oil content of pineapple mint, however, the essential oil compounds were significantly affected by salinity and Se-NPs- applications. Foliar application of Se-NPs- had a significant effect on piperitenone oxide, limonene, jasmone, viridiflorol and β-myrsene under different salinity levels. The highest percentage of piperitenone oxide (79.4%) as the major essential oil component was recorded in the no salinity treatment by applying 10 mg/L of nanoparticle. Interestingly, application of 10 mg L−1 Se-NPs- under 60 mM NaCl increased the piperitenone oxide content by 9.1% compared with non-sprayed plants. Finally, the obtained results demonstrated that foliar application of Se-NPs (10 mg L−1) can improve the pineapple mint growth and secondary metabolites profile under saline conditions.

Salinity, a severe worldwide issue, compromises the economic production of medicinal plants including mints and causes drug-yield decline. γ-Aminobutyric acid (GABA) is a tolerance-inducing signaling bio-molecule in various plant physiological processes. Pineapple mint ( Mentha suaveolens Ehrh.) is a valuable medicinal herb with an exhilarating scent of citrus fruit. Piperitenone oxide is the major bioactive constituent of its essential oil, having significant demand by pharmaceutical industries. Nonetheless, modeling and optimizing the effective concentration of GABA remain within twin foci of interest. Therefore, a two factor-five level (NaCl 0-150 mM and GABA 0-2.4 mM) central composite design was conducted to model and optimize drug yield and physiological responses of M . suaveolens . Based on the design of experiments (DoE) approach, different linear, quadratic, cubic, and quartic models were assigned to the response variables. Change trends of shoot and root dry weights followed a simple linear model, whereas sophisticated models (i.e., multiple polynomial regression) were fitted to the other traits. NaCl stress inevitably reduced root and shoot dry weight, piperitenone oxide content, relative water content, pigments content, and maximum quantum yield of PSII. However, content of malondialdehyde (MDA) and total flavonoid, and DPPH radical scavenging activity were increased under salinity. Under severe NaCl stress (150 mM), the essential oil content (0.53%) was increased three times in comparison with control (0.18%). Optimization analysis demonstrated that the highest amount of essential oil (0.6%) and piperitenone oxide (81%) as a drug yield-determining component would be achievable by application of 0.1–0.2 mM GABA under 100 mM NaCl. The highest dry weight of root and shoot was predicted to be achieved at 2.4 mM GABA. Overall, extremely severe NaCl stress (i.e., more than 100 mM) in which a sharp drop in yield components value was observed seemed to be out of M. suaveolens salinity tolerance range. Hence, it is rationale to compensate the decrease of drug yield by foliar application of a dilute GABA solution (i.e., 0.1–0.2 mM) under 100 mM NaCl stress or lower levels.

This work was aimed at correlating the chemotype of three Mentha species cultivated in Romania with an in vivo study of the anti-inflammatory and antinociceptive effects of essential oils. The selected species were Mentha piperita L. var. pallescens (white peppermint), Mentha spicata L. subsp. crispata (spearmint), and Mentha suaveolens Ehrh. (pineapple mint). Qualitative and quantitative analysis of the essential oils isolated from the selected Mentha species was performed by gas chromatography coupled with mass spectrometry (GC-MS). The anti-inflammatory activity of the essential oils was determined by the rat paw edema test induced by λ-carrageenan. The antinociceptive effect of the essential oils was evaluated by the writhing test in mice, using 1% (v/v) acetic acid solution administered intraperitonealy and by the hot plate test in mice. The results showed a menthol chemotype for M. piperita pallescens, a carvone chemotype for M. spicata, and a piperitenone oxide chemotype for M. suaveolens. The essential oil from M. spicata L. (EOMSP) produced statistically significant and dose-dependent anti-inflammatory and antinociceptive effects.