Toxicity, repellency, and anti-cholinesterase activities of bioactive molecules from clove buds Syzygium aromaticum L. as an ecological alternative in the search for control Hyalomma scupense (Acari: Ixodidae)

Introduction: The goal of the current study is to evaluate the acaricidal and repellent properties of the ethanolic extract, essential oil, and primary component eugenol from Syzygium aromaticum against Hyalomma scupense cattle ticks. Their potential mechanisms of action were also examined, using an in vitro assay. Methods: Clove essential oil was extracted using hydrodistillation technique. Gas chromatography-mass spectrometry (GC-MS) was performed to identify the chemical composition of clove. To evaluate the adulticidal, ovicidal, larvicidal and repellent proprieties of clove essential oil, eugenol and ethanolic extract on H. scupense, in vitro assays were performed using the adult immersion test (AIT), the ovicidal test, the larval packet test (LPT), the filter paper test and anti-acetylcholinesterase (AChE) activity. Results: After treatment, eugenol, the primary phytoconstituent of clove oil, which accounts for 97.66% of the whole oil, had 99.22% acaricide activity and inhibited egg hatching at a concentration of 10 mg/mL. Eugenol and clove essential oil showed potent adulticidal effect at high concentrations (10 mg/mL), achieving 100 and 93.76% mortality, respectively. The ethanolic extract exhibited moderate activity. At high concentration, the larvicidal activity of S. aromaticum oil, eugenol, and ethanolic extract were 100, 100, and 77.18%, respectively. In filter paper experiments, when tested at the concentration 5 mg/mL; eugenol showed the longest repellent effect up to 6 h. We also found that eugenol was the most active AChE inhibitor (IC50 = 0.178 mg/mL). Nevertheless, additional investigations are required to confirm the accurate mechanism and the relevance of clove in practical application. Conclusion: Overall, our research indicated that, because its effectiveness as acaricide, S. aromaticum essential oil and its phytoconstituent eugenol may offer an alternative source for the control of H. scupense cattle ticks

Efficacy of synergistic activity of seed oils from Carthamus tinctorius (Safflower) and Nasturtium officinale (Watercress) on the lethality of the cattle tick Hyalomma scupense (Acari: Ixodidae)

Background: Ticks and tick-borne diseases are a severe economic and public-health problem for cattle producers. The emergence of acaricide resistance to synthetic chemical treatments has prompted interest in developing alternative tickcontrol methods.Aim: The main objective of the current research was to identify the chemical structure of Carthamus tinctorius and Nasturtium officinale seed oils and to assess their anti-tick properties against Hyalomma scupense ticks both alone and in combination (1:1).Methods: Analytical methods were used to analyze the chemical components. For in vitro assays, adults of H. scupense were immersed in C. tinctorius and N. officinale seed oils at 100, 125, 200, and 300 mg/ml concentrations; for 5 minutes. Larvae of H. scupense were dipped in 25, 50, 100, 125, 200, and 300 mg/ml doses of seed oils; the mortality percentage was determined after 24 hours.Results: The seed oil safflower was mainly composed of linoleic acid (84.48%), followed by palmitic acid (6.54%) and stearic acid (3.77%). Meanwhile, watercress seed oil was mainly composed of linolenic acid (50.78%), gondoic acid (13.57%), linoleic acid (10.58%), palmitic acid (8.02%), and erucidic acid (6.62%). The Adults Immersion Test showed the sensitivity of ticks to C. tinctorius and N. officinale seed oil: C. tinctorius seed oil caused (95%) mortality of H. scupense at 300 mg/ml, while N. officinale seed oil induced (88.68%) mortality at the same concentration. At a 200 mg/ml concentration, C. tinctorius and N. officinale oil combined caused 100% mortality. Tested oils showed larvicidal efficacy. LC50 values for C. tinctorius and N. officinale seed oils were 84.16 and 61.78 mg/ml, respectively, in 24 hours. LC50 value of oils association (50% C. tinctorius: 50% N. officinale) was 47.96 mg/ml. The mixture of seed oils from two plants tested against H. scupense larvae and adult females at a 1:1 ratio showed synergistic interaction.Conclusion: Seed oils tested alone, and the mixture could be used as an alternative solution in the fight against ticks

Tunisian thyme essential iol for controlling enniatins producing fusarium species

International audienceEnniatins are emerging mycotoxins produced by Fusarium species. They are frequently found as contaminants in cereal grains in recent years. The synthesis of these secondary metabolites is often a response to biotic and abiotic stresses. Therefore, the introduction of fungicides into the environment of toxigenic fungi can lead to an increase in mycotoxin accumulation. The search for molecules with both antifungal and antimycotoxigenic activities is a challenge to preserve food safety. Essential oils (EOs) have a promising potential as natural fungicides and should be used both to control fungi and/or their mycotoxin production. In the present work, we extracted the essential oil of Tunisian Thymus capitatus and tested its effect in vitro on two enniatin-producing Fusarium strains when placed in contact with the mycelium in solid medium or used as a fumigant. In agar medium, contact tests measured with two different sets of EOs for a strain of Fusarium avenaceum provided an IC 5O of 0.05 µL EO mL-1. For another strain of Fusarium sp. it was found an IC 50 of 0.08 µL EO mL-1. Fungistatic activity induced no overproduction of enniatins and in contrast, decreases of 55% were found in some samples. Volatile components diffusing in a sealed container also had fungistatic activity that was both dose (5 to 25 µL 1.5 L-1) and time (6 to 24 days) dependent. No fungal acclimation to the EOs and no persistent effect of the EOs were observed, but the decrease in protective effect with increasing incubation time was probably due to EOs alterations

TUNISIAN THYME ESSENTIAL OIL FOR CONTROLLING ENNIATINS PRODUCING FUSARIUM SPECIES

Enniatins are emerging mycotoxins produced by Fusarium species. They are frequently found as contaminants in cereal grains in recent years. The synthesis of these secondary metabolites is often a response to biotic and abiotic stresses. Therefore, the introduction of fungicides into the environment of toxigenic fungi can lead to an increase in mycotoxin accumulation. The search for molecules with both antifungal and antimycotoxigenic activities is a challenge to preserve food safety. Essential oils (EOs) have a promising potential as natural fungicides and should be used both to control fungi and/or their mycotoxin production. In the present work, we extracted the essential oil of Tunisian Thymus capitatus and tested its effect in vitro on two enniatin-producing Fusarium strains when placed in contact with the mycelium in solid medium or used as a fumigant. In agar medium, contact tests measured with two different sets of EOs for a strain of Fusarium avenaceum provided an IC5O of 0.05 μL EO mL-1. For another strain of Fusarium sp. it was found an IC50 of 0.08 μL EO mL-1. Fungistatic activity induced no overproduction of enniatins and in contrast, decreases of 55% were found in some samples. Volatile components diffusing in a sealed container also had fungistatic activity that was both dose (5 to 25 μL 1.5 L-1) and time (6 to 24 days) dependent. No fungal acclimation to the EOs and no persistent effect of the EOs were observed, but the decrease in protective effect with increasing incubation time was probably due to EOs alterations

Nano-Emulsification of Cinnamon and Curcuma Essential Oils for the Quality Improvement of Minced Meat Beef

This work aims to evaluate cinnamon and curcuma essential oils as natural preservatives in minced beef meat. Essential oil chemical compositions and antibacterial activities were studied, and their encapsulation was optimized into nano-emulsions based on droplet size and distribution assessments. Selected formulas were further explored for their physical stabilities and antibacterial activities. Then, their effects on minced beef meat preservation were evaluated. Results showed significant differences in the chemical compositions and the efficiency of the tested essential oils, with cinnamon having a significant antibacterial efficacy. Formulation results showed that cinnamon nanoemulsion, encapsulated by 7.5% Tween 80, possessed an 89 nm droplet size, while the droplet diameter of curcuma nanoemulsion, encapsulated by 5% Tween 80, was 151 nm. Antimicrobial results depicted a significantly higher activity in nanoemulsions as compared to essential oils. For instance, the inhibition diameter of cinnamon essential oils against S. aureus was equal to 35 mm, while that of its nanoemulsion reached 40 mm. The meat preservation results showed that both bulk and nanoencapsulated essential oils significantly inhibited bacterial growth, as well as the formation of methemoglobin and lipid oxidation in meat. Thus, this work draws attention to the enhanced preservation effects of essential oils on the processing of minced beef meat as well as the great potential of nanoemulsions as carriers for essential oils in food industry applications

Activity assessment of tomato endophytic bacteria bioactive compounds for the postharvest biocontrol of Botrytis cinerea

International audienc

Essential oil composition, phenolic compound, and antioxidant potential of Inulaviscosa as affected by extraction process

The purpose of this study was to compare the essential oil composition of Inula viscosa leaves by hydrodistillation (HDE), ultrasonic (UDE) and solvent (SE) extractions followed by hydrodistillation. The total polyphenol and flavonoid contents and their antioxidant effects were studied by different solvent of extraction: ethanol (ET), ethyl acetate (EA), methanol (ME) and aqueous (AE). The principal compounds for HDE were: 2-hexenal (3.70%), caryophyllene oxide (3.11%), γ-selinene (3.09%), 3-hexen-1-ol (2.00%), eugenol (1.70%) and trans-caryophyllene (1.34%), while for UDE were: γ-selinene (5.68%), caryophyllene oxide (4.87%), trans-caryophyllene (1.99%) and nerolidol (1.74%). The oil obtained by SE was shown to contain tridecane (3.89%), dodecane (3.08%), trans-caryophyllene (2.94%), caryophyllene oxide (2.56%) and nerolidol (2.53%). Significant changes on phenolic contents were found between the different solvent of extraction. ME and AE extracts led to the highest total polyphenol (PHL) and flavonoid (FL) amounts. The anti-radical activity and reducing power were maximal in AE and ME extract. HPLC examination established that the ferulic acid as major phenolic acid in ME and AE fractions, whereas luteolin was the main compound of EA and ET fractions