Seasonal Effect on the Chemical Composition, Insecticidal Properties and Other Biological Activities of Zanthoxylum leprieurii Guill. & Perr. Essential oils

Spice-Derived Phenolic Compounds: Potential for Skin Cancer Prevention and Therapy

Skin cancer is a condition characterized by the abnormal growth of skin cells, primarily caused by exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. Different types of skin cancer include melanoma, basal cell carcinoma, and squamous cell carcinoma. Despite the advancements in targeted therapies, there is still a need for a safer, highly efficient approach to preventing and treating cutaneous malignancies. Spices have a rich history dating back thousands of years and are renowned for their ability to enhance the flavor, taste, and color of food. Derived from various plant parts like seeds, fruits, bark, roots, or flowers, spices are important culinary ingredients. However, their value extends beyond the culinary realm. Some spices contain bioactive compounds, including phenolic compounds, which are known for their significant biological effects. These compounds have attracted attention in scientific research due to their potential health benefits, including their possible role in disease prevention and treatment, such as cancer. This review focuses on examining the potential of spice-derived phenolic compounds as preventive or therapeutic agents for managing skin cancers. By compiling and analyzing the available knowledge, this review aims to provide insights that can guide future research in identifying new anticancer phytochemicals and uncovering additional mechanisms for combating skin cancer.

Activity of the genus Zanthoxylum against diseases caused by protozoa: A systematic review

Neglected diseases (NDs) are treated with a less varied range of drugs, with high cost and toxicity, which makes the search for therapeutic alternatives important. In this context, plants, such as those from the genus Zanthoxylum, can be promising due to active substances in their composition. This study evaluates the potential of species from this genus to treat NDs. Initially, a protocol was developed to carry out a systematic review approved by Prospero (CRD42020200438). The databases PubMed, BVS, Scopus, Science Direct, and Web of Science were used with the following keywords: "zanthoxylum," "xanthoxylums," "fagaras," "leishmaniasis," "chagas disease," "malaria," and "African trypanosomiasis." Two independent evaluators analyzed the title and abstract of 166 articles, and 122 were excluded due to duplicity or for not meeting the inclusion criteria. From the 44 selected articles, results of in vitro/in vivo tests were extracted. In vitro studies showed that Z. rhoifolium, through the alkaloid nitidine, was active against Plasmodium (IC50 <1 μg/ml) and Leishmania (IC50 <8 μg/ml), and selective for both (>10 and >30, respectively). For Chagas disease, the promising species (IC50 <2 μg/ml) were Z. naranjillo and Z. minutiflorum, and for sleeping sickness, the species Z. zanthoxyloides (IC50 <4 μg/ml) stood out. In the in vivo analysis, the most promising species were Z. rhoifolium and Z. chiloperone. In summary, the species Z. rhoifolium, Z. naranjillo, Z. minutiflorum, Z. zanthoxyloides, and Z. chiloperone are promising sources of active molecules for the treatment of NDs.

Antifungal and antimycotoxic activities of 3 essential oils against 3 mycotoxinogenic fungi

Fungal toxins can have various adverse health effects, including carcinogenic, teratogenic or hepatotoxic impacts. In addition, fungal alteration has also a negative impact on agricultural plant production. The use of chemical fungicides to control mycotoxin contamination is increasingly controversial and regulated. More environmentally friendly methods are therefore being explored. Essential oils, as compounds extracted from plants, are liquids whose specific aromatic compounds give each essential oil its own unique characteristics. Due to their rich chemical composition, essential oils (EOs) have many interesting properties, including antifungal activities. The objective of the present study was to analyze volatile chemical composition of EOs (Cymbopogon schoenanthus, Cymbopogon nardus and Eucalyptus camaldulensis) by GC/MS and to investigate their effects on the growth, sporulation and mycotoxin production of Aspergillus flavus, Aspergillus carbonarius and Fusarium verticillioides (aflatoxin B1, ochratoxin A and fumonisin B1, respectively). In addition, EOs influence on aflatoxin B1 (AFB1) and fumonisin B1 (FB1) biosynthesis pathways was explored using real-time qRT-PCR. The results obtained in vitro, by direct contact with the EOs and by diffusion of their volatile compounds, showed that the essential oils had inhibitory effects on the growth and the production of mycotoxins of the 3 fungal strains and modified the expression of some toxin synthesis genes. We conclude that the recorded effects were dependent on the combined effects of the EOs type, the fungal strains and the doses studied.

Cinnamomum zeylanicum Essential Oil Formulation with Poly(propylene imine) Dendrimers with Surface-Grafted Glycerol: Release Kinetics of trans-Cinnamaldehyde and Germination Inhibition Effects

The Third-generation glycerodendrimer polypropylenimine (GD-PPI-3) can be used in an aqueous formulation of Cinnamomum zeylanicum essential oil (CEO). The purpose was to give an overview of this innovative method of retaining and releasing essential oils. The formulation consisted of 366 min stirring at 1735 rpm of the aqueous solution of 2 mM GD-PPI-3 with CEO. Some physicochemical properties of these formulations, as well as the release of trans-cinnamaldehyde, have been studied. A bimodal distribution and no concentration or aging effect were observed by optical microscopy. Moreover, the release kinetics showed the retention of volatile molecules in solution under various environmental conditions. The release profile was characterized by an initial burst followed by a steady release. The dendrimers allowed us to reduce this initial burst and extended the release by at least 15 h. In addition, the herbicidal effect was evaluated: inhibition of Arabidopsis thaliana seed germination was obtained for 7 days with a formulation of 12.5 mg/L CEO in a closed space and 360 mg/L CEO in an open space.

Variation in compositions and biological activities of essential oils from four Citrus species: Citrus limon, Citrus sinensis, Citrus paradisi, and Citrus reticulata

Species of the genus Citrus are cultivated in many regions of China and are widely used for medicinal purposes. In the present study, essential oils (EOs) were extracted from four different Citrus species using steam distillation. The chemical components of these four essential oils were separated using gas chromatography-mass spectrometry, and 56 compounds were confirmed. D-limonene was found to be the most abundant compound. All four essential oils demonstrated varied but remarkable radical scavenging capacity (IC50; 0.77-13.9%). Citrus paradisi essential oil exhibited excellent antioxidant activity. Compared to ibuprofen, topical application of the four Citrus spp. essential oils significantly inhibited ear edema formation in mice. Furthermore, essential oils from the four Citrus species reduced the expression levels of interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and nuclear transcription factor kappa B p65 (NF-κB) to different degrees. The cytotoxicity of the four essential oils on BV2 microglial cells was determined using the MTT assay (IC50; 321.37-1558.87 μg/mL), wherein Citrus limon essential oil showed the lowest cytotoxicity. The essential oils of Citrus limon, Citrus reticulata, and Citrus paradisi had an inhibitory effect on the lung cancer cell line H1299 by inducing a G0/G1 cell cycle arrest. Cluster and principal component analyses were used to determine the relationship among the Citrus species. These results suggest that the four Citrus essential oils have potential for use as active ingredients in functional foods or cosmeceutical products.

Toxicity, Deterrent and Repellent Activities of Four Essential Oils on Aphis punicae (Hemiptera: Aphididae)

Chemical insecticides have many harmful effects, including as foodborne residues and environmental contaminants, as well as side effects on natural enemies and serious risks for human health. The use of plant-derived essential oils (EOs) as effective bio-agents has become an essential component of integrated pest management. In this study, the contact toxicity, deterrent, and repellent activities were evaluated for essential oils obtained from Mentha piperita, Mentha longifolia, Salvia officinalis, and Salvia rosmarinus, grown at high altitudes in the Taif region, KSA, on Aphis punicae. Furthermore, the toxicity of these EOs against the predator Coccinella undecimpunctata was estimated. A total of 17, 14, 16, and 26 compounds were identified in the EOs of M. piperita, M. longifolia, S. officinalis, and S. rosmarinus, respectively. They showed a variation in the major compounds: M. piperita (Carvone, 61.16%), M. longifolia (Pulegone, 48.6%), S. officinalis (Eucalyptol, 33.52%), and S. rosmarinus (α-pinene, 36.65%). A contact toxicity test on A. punicae imago and C. undecimpunctata larvae showed that LC₅₀ were approximately four-fold greater for all tested EOs towards aphids compared to towards the predator, while the two species of Salvia sp. were more effective than the other two species of Mentha sp. The LC₅₀ values on A. punicae ranged from 1.57 to 2.97 µg/mL, while on C. undecimpunctata larvae, they ranged from 5.96 to 10.33 µg/mL. Furthermore, the EOs of two species of Salvia sp. showed excellent repellence and deterrence against A. punicae. In conclusion, the tested EOs, especially those from Salvia sp., have been shown to be promising natural aphicides, repellent, and deterrent against A. punicae, and they are safe for important insect predators.

Essential Oil-Based Bioherbicides: Human Health Risks Analysis

In recent years, the development of new bio-based products for biocontrol has been gaining importance as it contributes to reducing the use of synthetic herbicides in agriculture. Conventional herbicides (i.e., the ones with synthetic molecules) can lead to adverse effects such as human diseases (cancers, neurodegenerative diseases, reproductive perturbations, etc.) but also to disturbing the environment because of their drift in the air, transport throughout aquatic systems and persistence across different environments. The use of natural molecules seems to be a very good alternative for maintaining productive agriculture but without the negative side effects of synthetic herbicides. In this context, essential oils and their components are increasingly studied in order to produce several categories of biopesticides thanks to their well-known biocidal activities. However, these molecules can also be potentially hazardous to humans and the environment. This article reviews the state of the literature and regulations with regard to the potential risks related to the use of essential oils as bioherbicides in agricultural and horticultural applications.

Comparative Study of Fig Volatile Compounds Using Headspace Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry: Effects of Cultivars and Ripening Stages

Aroma is one of the essential parameters that determine fruit quality. It is also an important feature of varietal characterization and so valuable for agro-biodiversity identification and preservation. In order to characterize changes in the aroma fingerprint through fig development, the main objective of the present research was to study the volatile organic compound (VOC) profiles of figs (Ficus carica L.) from three cultivars, Taamriwthe (TH), Azegzaw (AZ), and Averkane (AV), at three ripening stages (unripe, ripe, and fully ripe). Analyses was performed using Headspace Solid-phase Microextraction and gas chromatography coupled with mass spectrometry. Results revealed the presence of 29 compounds that were grouped into different chemical classes. Aldehydes comprised the most abundant VOCs identified in all the studied figs, while alcohols, ketones, and terpenes comprised the minor compounds found in TH, AZ, and AV figs, respectively. Different aroma descriptors were identified throughout the ripening stages of figs; fruity and green aromas were dominant in all cultivars, while a fatty aroma scarcely occurred in figs. A gallery plot representation demonstrated that certain VOCs differentiate the studied cultivars and the different ripening stages of figs. Principal component analysis findings demonstrated characteristic VOCs of distinct ripening stages and cultivars, those VOCs can be used as fingerprints to distinguish different cultivars and/or ripening stages.

Comprehensive SPME-GC-MS Analysis of VOC Profiles Obtained Following High-Temperature Heating of Pork Back Fat with Varying Boar Taint Intensities

Boar taint detection is a major concern for the pork industry. Currently, this taint is mainly detected through a sensory evaluation. However, little is known about the entire volatile organic compounds (VOCs) profile perceived by the assessor. Additionally, many research groups are working on the development of new rapid and reliable detection methods, which include the VOCs sensor-based methods. The latter are susceptible to sensor poisoning by interfering molecules produced during high-temperature heating of fat. Analyzing the VOC profiles obtained by solid phase microextraction gas chromatography–mass spectrometry (SPME-GC-MS) after incubation at 150 and 180 °C helps in the comprehension of the environment in which boar taint is perceived. Many similarities were observed between these temperatures; both profiles were rich in carboxylic acids and aldehydes. Through a principal component analysis (PCA) and analyses of variance (ANOVAs), differences were highlighted. Aldehydes such as (E,E)-nona-2,4-dienal exhibited higher concentrations at 150 °C, while heating at 180 °C resulted in significantly higher concentrations in fatty acids, several amide derivatives, and squalene. These differences stress the need for standardized parameters for sensory evaluation. Lastly, skatole and androstenone, the main compounds involved in boar taint, were perceived in the headspace at these temperatures but remained low (below 1 ppm). Higher temperature should be investigated to increase headspace concentrations provided that rigorous analyses of total VOC profiles are performed.

Biopesticide Trunk Injection Into Apple Trees: A Proof of Concept for the Systemic Movement of Mint and Cinnamon Essential Oils

The use of conventional pesticides is debated because of their multiple potential adverse effects on non-target organisms, human health, pest resistance development and environmental contaminations. In this setting, this study focused on developing alternatives, such as trunk-injected essential oil (EO)-based biopesticides. We analysed the ecophysiology of apple trees (Malus domestica) following the injection of Cinnamomum cassia and Mentha spicata nanoemulsions in the tree's vascular system. Targeted and untargeted volatile organic compounds (VOCs) analyses were performed on leaf-contained and leaf-emitted VOCs and analysed through dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS) and thermal desorption unit (TDU)-GC-MS. Our results showed that carvone, as a major constituent of the M. spicata EO, was contained in the leaves (mean concentrations ranging from 3.39 to 19.7 ng g_DW ^-1) and emitted at a constant rate of approximately 0.2 ng g_DW ^-1 h^-1. Trans-cinnamaldehyde, C. cassia's major component, accumulated in the leaves (mean concentrations of 83.46 and 350.54 ng g_DW ^-1) without being emitted. Furthermore, our results highlighted the increase in various VOCs following EO injection, both in terms of leaf-contained VOCs, such as methyl salicylate, and in terms of leaf-emitted VOCs, such as caryophyllene. Principal component analysis (PCA) highlighted differences in terms of VOC profiles. In addition, an analysis of similarity (ANOSIM) and permutational multivariate analysis of variance (PERMANOVA) revealed that the VOC profiles were significantly impacted by the treatment. Maximum yields of photosystem II (Fv/Fm) were within the range of 0.80-0.85, indicating that the trees remained healthy throughout the experiment. Our targeted analysis demonstrated the systemic translocation of EOs through the plant's vascular system. The untargeted analysis, on the other hand, highlighted the potential systemic acquired resistance (SAR) induction by these EOs. Lastly, C. cassia and M. spicata EOs did not appear phytotoxic to the treated trees, as demonstrated through chlorophyll fluorescence measurements. Hence, this work can be seen as a proof of concept for the use of trunk-injected EOs given the systemic translocation, increased production and release of biogenic VOCs (BVOCs) and absence of phytotoxicity. Further works should focus on the ecological impact of such treatments in orchards, as well as apple quality and production yields.

Insecticidal Activity of 25 Essential Oils on the Stored Product Pest, Sitophilus granarius

The granary weevil Sitophilus granarius is a stored product pest found worldwide. Environmental damages, human health issues and the emergence of resistance are driving scientists to seeks alternatives to synthetic insecticides for its control. With low mammal toxicity and low persistence, essential oils are more and more being considered a potential alternative. In this study, we compare the toxicity of 25 essential oils, representing a large array of chemical compositions, on adult granary weevils. Bioassays indicated that Allium sativum was the most toxic essential oil, with the lowest calculated lethal concentration 90 (LC90) both after 24 h and 7 days. Gaultheria procumbens, Mentha arvensis and Eucalyptus dives oils appeared to have a good potential in terms of toxicity/cost ratio for further development of a plant-derived biocide. Low influence of exposure time was observed for most of essential oils. The methodology developed here offers the possibility to test a large array of essential oils in the same experimental bioassay and in a standardized way. It is a first step to the development of new biocide for alternative management strategies of stored product pests.

Use of New Glycerol-Based Dendrimers for Essential Oils Encapsulation: Optimization of Stirring Time and Rate Using a Plackett-Burman Design and a Surface Response Methodology

Essential oils are used in an increasing number of applications including biopesticides. Their volatility minimizes the risk of residue but can also be a constraint if the release is rapid and uncontrolled. Solutions allowing the encapsulation of essential oils are therefore strongly researched. In this study, essential oils encapsulation was carried out within dendrimers to control their volatility. Indeed, a spontaneous complexation occurs in a solution of dendrimers with essential oils which maintains it longer. Six parameters (temperature, stirring rate, relative concentration, solvent volume, stirring time, and pH) of this reaction has been optimized by two steps: first a screening of the parameters that influence the encapsulation with a Plackett-Burmann design the most followed by an optimization of those ones by a surface response methodology. In this study, two essential oils with herbicide properties were used: the essential oils of Cinnamomum zeylanicum Blume and Cymbopogon winterianus Jowitt; and four biosourced dendrimers: glycerodendrimers derived from polypropylenimine and polyamidoamine, a glyceroclikdendrimer, and a glyceroladendrimer. Meta-analysis of all Plackett-Burman assays determined that rate and stirring time were effective on the retention rate thereby these parameters were used for the surface response methodology part. Each combination gives a different optimum depending on the structure of these molecules.

Phytotoxicity of Essential Oils: Opportunities and Constraints for the Development of Biopesticides. A Review

The extensive use of chemical pesticides leads to risks for both the environment and human health due to the toxicity and poor biodegradability that they may present. Farmers therefore need alternative agricultural practices including the use of natural molecules to achieve more sustainable production methods to meet consumer and societal expectations. Numerous studies have reported the potential of essential oils as biopesticides for integrated weed or pest management. However, their phytotoxic properties have long been a major drawback for their potential applicability (apart from herbicidal application). Therefore, deciphering the mode of action of essential oils exogenously applied in regards to their potential phytotoxicity will help in the development of biopesticides for sustainable agriculture. Nowadays, plant physiologists are attempting to understand the mechanisms underlying their phytotoxicity at both cellular and molecular levels using transcriptomic and metabolomic tools. This review systematically discusses the functional and cellular impacts of essential oils applied in the agronomic context. Putative molecular targets and resulting physiological disturbances are described. New opportunities regarding the development of biopesticides are discussed including biostimulation and defense elicitation or priming properties of essential oils.

Effects of Origanum vulgare essential oil and its two main components, carvacrol and thymol, on the plant pathogen Botrytis cinerea

Background

Botrytis cinerea causes serious gray mold disease in many plants. This pathogen has developed resistance to many fungicides. Thus, it has become necessary to look for new safe yet effective compounds against B. cinerea.

Methods

Essential oils (EOs) from 17 plant species were assayed against B. cinerea, of which Origanum vulgare essential oil (OVEO) showed strong antifungal activity, and accordingly its main components were detected by GC/MS. Further study was conducted on the effects of OVEO, carvacrol and thymol in vitro on mycelium growth and spore germination, mycelium morphology, leakages of cytoplasmic contents, mitochondrial injury and accumulation of reactive oxygen species (ROS) of B. cinerea. The control efficacies of OVEO, carvacrol and thymol on tomato gray mold were evaluated in vivo.

Results

Of all the 17 plant EOs tested, Cinnamomum cassia, Litsea cubeba var. formosana and O. vulgare EOs had the best inhibitory effect on B. cinerea, with 0.5 mg/mL completely inhibiting the mycelium growth of B. cinerea. Twenty-one different compounds of OVEO were identified by gas chromatography–mass spectrometry, and the main chemical components were carvacrol (89.98%), β-caryophyllene (3.34%), thymol (2.39%), α-humulene (1.38%) and 1-methyl-2-propan-2-ylbenzene isopropyl benzene (1.36%). In vitro experiment showed EC₅₀ values of OVEO, carvacrol and thymol were 140.04, 9.09 and 21.32 μg/mL, respectively. Carvacrol and thymol completely inhibited the spore germination of B. cinerea at the concentration of 300 μg/mL while the inhibition rate of OVEO was 80.03%. EC₅₀ of carvacrol and thymol have significantly (P < 0.05) reduced the fresh and dry weight of mycelia. The collapse and damage on B. cinerea mycelia treated with 40 μg/mL of carvacrol and thymol was examined by scanning electron microscope (SEM). Through extracellular conductivity test and fluorescence microscope observation, it was found that carvacrol and thymol led to increase the permeability of target cells, the destruction of mitochondrial membrane and ROS accumulation. In vivo conditions, 1000 μg/mL carvacrol had the best protective and therapeutic effects on tomato gray mold (77.98% and 28.04%, respectively), and the protective effect was significantly higher than that of 400 μg/mL pyrimethanil (43.15%). While the therapeutic and protective effects of 1,000 μg/mL OVEO and thymol were comparable to chemical control.

Conclusions

OVEO showed moderate antifungal activity, whereas its main components carvacrol and thymol have great application potential as natural fungicides or lead compounds for commercial fungicides in preventing and controlling plant diseases caused by B. cinerea.

Evaluation of Drimys winteri (Canelo) Essential Oil as Insecticide against Acanthoscelides obtectus (Coleoptera: Bruchidae) and Aegorhinus superciliosus (Coleoptera: Curculionidae)

Adverse effects caused by synthetic pesticides have increased interest in plant-derived insecticidal compounds, in particular essential oils, as a more compatible and ecofriendly alternative for pest control of economic importance. For this reason, the essential oil isolated from leaves and shoots of Drimys winteri (J.R. Forster & G. Forster)-also named canelo (CEO)-was investigated for its chemical profile and insecticidal action against Acanthoscelides obtectus (Say)-one of the most important post-harvest pests of dry beans in the world-and Aegorhinus superciliosus (Guérin)-a significant pest of fruit trees in Chile. The analysis by gas chromatography, paired with mass spectrometry (GC/MS) determined 56 compounds, corresponding to 92.28% of the detected compounds. Elemol (13.54%), γ-eudesmol (11.42%), β-eudesmol (8.49%), α-eudesmol (6.39%), α-pinene (7.92%) and β-pinene (5.17%) were the most abundant. Regarding the bioactivity of the CEO, the results demonstrated toxicological effects against A. obtectus. A concentration of 158.3 µL L^-1 had a mortality rate of 94% after 24 h exposure. The LC₅₀ and LC₉₀ values at 24 h were 60.1 and 163.0 µL L^-1. Moreover, behavioral bioassays showed a repellent effect against A. superciliosus with a dose of one microliter of CEO. Both sexes of the raspberry weevil stayed for very short times in the treated area with the oil (<0.8 min), showing a homogeneous repellency in the species. The overall data suggest that canelo leaves and shoots essential oil has an insecticide effect and is worth exploring to better understand the synergistic relationship between the compounds present in the essential oil.