Citronellal improves endothelial dysfunction by affecting the stability of the GCH1 protein.

Endothelial dysfunction (ED) serves as the pathological basis for various cardiovascular diseases. Guanosine triphosphate cyclopyrrolone 1 (GCH1) emerges as a pivotal protein in sustaining nitric oxide (NO) production within endothelial cells, yet it undergoes degradation under oxidative stress, contributing to endothelial cell dysfunction. Citronellal (CT), a monoterpenoid, has been shown to ameliorate endothelial dysfunction induced by in atherosclerosis rats. However, whether CT can inhibit the degradation of GCH1 protein is not clear. It has been reported that ubiquitination may play a crucial role in regulating GCH1 protein levels and activities. However, the specific E3 ligase for GCH1 and the molecular mechanism of GCH1 ubiquitination remain unclear. Using data-base exploration analysis, we find that the levels of the E3 ligase Smad-ubiquitination regulatory factor 2 (Smurf2) negatively correlate with those of GCH1 in vascular tissues and HUVECs. We observe that Smurf2 interacts with GCH1 and promotes its degradation via the proteasome pathway. Interestingly, ectopic Smurf2 expression not only decreases GCH1 levels but also reduces cell proliferation and reactive oxygen species (ROS) levels, mostly because of increased GCH1 accumulation. Furthermore, we identify BH 4/eNOS as downstream of GCH1. Taken together, our results indicate that CT can obviously improve vascular endothelial injury in Type 1 diabetes mellitus (T1DM) rats and reverse the expressions of GCH1 and Smurf2 proteins in aorta of T1DM rats. Smurf2 promotes ubiquitination and degradation of GCH1 through proteasome pathway in HUVECs. We conclude that the Smurf2-GCH1 interaction might represent a potential target for improving endothelial injury.

Genetic architecture of the toxicological response to eucalyptol and citronellal in Drosophila melanogaster.

The excessive and indiscriminate use of synthetic insecticides has led to environmental pollution, wildlife destruction, and adverse effects on human health, while simultaneously giving rise to resistance in insect pest populations. This adaptive trait is expressed through various mechanisms, such as changes in the cuticle, heightened activities of detoxifying enzymes, and alterations in the sites of action that reduce their affinity for insecticides. In this context, we associate variation in toxicological response with genomic variation, to identify genetic polymorphisms underlying the different steps of the insect (genotype)-response (phenotype)-insecticide (environment) interaction. Under this framework, our objective was to investigate the genetic factors involved in the toxicological response of D. melanogaster lines when exposed to citronellal and eucalyptol vapors (monoterpenes of plant origin). We quantified KT50 in adult males, representing the time necessary for half of the exposed individuals to be turned upside down (unable to walk or fly). Since the genomes of all lines used are completely sequenced, we perform a Genome Wide Association Study to analyze the genetic underpinnings of the toxicological response. Our investigation enabled the identification of 656 genetic polymorphisms and 316 candidate genes responsible for the overall phenotypic variation. Among these, 162 candidate genes (77.1%) exhibited specificity to citronellal, 45 (21.4%) were specific to eucalyptol, and 3 candidate genes (1.5%) namely CG34345, robo2, and Ac13E, were implicated in the variation for both monoterpenes. These suggest a widespread adaptability in the response to insecticides, encompassing genes influenced by monoterpenes and those orchestrating resistance to the toxicity of these compounds.

Exploring Citronella's inhibitory mechanism against Listeria monocytogenes and its utilization in preserving cheese.

Listeria monocytogenes presents significant risk to human health due to its high resistance and capacity to form toxin-producing biofilms that contaminate food. The objective of this study was to assess the inhibitory effect of citronella aldehyde (CIT) on L. monocytogenes and investigate the underlying mechanism of inhibition. The results indicated that the minimum inhibitory concentration (MIC) and Minimum sterilisation concentration (MBC) of CIT against L. monocytogenes was 2 µL/mL. At this concentration, CIT was able to effectively suppress biofilm formation and reduce metabolic activity. Crystalline violet staining and MTT reaction demonstrated that CIT was able to inhibit biofilm formation and reduce bacterial cell activity. Furthermore, the motility assessment assay revealed that CIT inhibited bacterial swarming and swimming. Scanning electron microscopy (SEM) and laser confocal microscopy (LSCM) observations revealed that CIT had a significant detrimental effect on L. monocytogenes cell structure and biofilm integrity. LSCM also observed that nucleic acids of L. monocytogenes were damaged in the CIT-treated group, along with an increase in bacterial extracellular nucleic acid leakage. The proteomic results also confirmed the ability of CIT to affect the expression of proteins related to processes including metabolism, DNA replication and repair, transcription and biofilm formation in L. monocytogenes. Consistent with the proteomics results are ATPase activity and ATP content of L. monocytogenes were significantly reduced following treatment with various concentrations of CIT. Notably, CIT showed good inhibitory activity against L. monocytogenes on cheese via fumigation at 4 °C.This study establishes a foundation for the potential application of CIT in food safety control.

Safety and efficacy of a feed additive consisting of an essential oil derived from the leaves of Cymbopogon nardus (L.) Rendle (citronella oil) for use in all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of citronella oil obtained from the leaves of Cymbopogon nardus (L.) Rendle, when used as a sensory additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that citronella oil from C. nardus is of low concern for long-living and reproductive animals at the use levels in complete feed of 3.5 mg/kg for laying hens and rabbits, 6 mg/kg for sows and dairy cows, 9.5 mg/kg for sheep/goats and horses, 2.0 mg/kg for cats and 10 mg/kg for dogs. For short-living animals (species for fattening), the additive was considered of no concern at concentrations of 18 mg/kg in chickens for fattening, 24 mg/kg in turkeys for fattening, 20 mg/kg for piglets, pigs for fattening, veal calves (milk replacer), cattle for fattening, sheep/goats for meat production, horses for meat production and rabbits for meat production, and 30 mg/kg for salmonids. The conclusions were extrapolated to physiologically related minor species. For any other species, the additive is considered of low concern at 2.0 mg/kg complete feed. The use of citronella oil in animal feed is expected to be of no concern for the consumers and for the environment. The essential oil under assessment should be considered as irritant to skin and eyes and as a dermal sensitiser. When handling the essential oil, exposure of unprotected users to methyleugenol may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since the leaves of C. nardus and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Polyvinyl Butyral Loading with Combined Repellents Showed Effective Protection Against Leech Bites in Diverse Situations.

Background: Leech bites have long been a persistent problem for individuals engaged in outdoor activities, particularly in environments such as moors, jungles, and grasslands. Methods to prevent leech bites are anecdotal and individual, highlighting the need for the development of universal and effective repellent formulations. This study developed a novel approach for repelling leeches using combined repellent agents and a film-forming material (polyvinyl butyral), to enhance efficiency in multi-scenario applications. Material and methods: This study demonstrates that citronellal, icaridin and DDAC (didecyl dimethyl ammonium chloride) showcasing active avoidance and contact toxicity on leeches. the optimized repellent formulation (MSRS, containing citronellal, icaridin and DDAC as repellent agents) enables specific sustained release properties of constituents in both air and water conditions. Results: MSRS could effectively achieve the purposes of "proactive repelling", "contact repelling", and "bite detaching". The effectiveness could last for several hours. Additionally, the hydrophobic polyvinyl butyral membrane reduced the transdermal absorption of repellent agents. Moreover, the formulation is biocompatible and environmentally friendly. Conclusions: This study provides a new feasible strategy for the prevention and removal of leech bites.

Nanofabrication of citronellal with chitosan biopolymer to boost its efficacy against aflatoxin B1 and Aspergillus flavus mediated biodeterioration of active ingredient of Piper longum.

The study reports the efficacy of nanofabricated citronellal inside the chitosan biopolymer (NeCn) against Aspergillus flavus growth, aflatoxin B1 (AFB1) production, and active ingredient biodeterioration (Piperine) in Piper longum L. The prepared NeCn was characterized by Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and Fourier Transform Infrared Spectroscopy (FTIR). The results revealed that the NeCn exhibited distantly improved antifungal (1.25 µL/mL) and AFB1 inhibition (1.0 µL/mL) compared to free Cn. The perturbances in membrane function, mitochondrial membrane potential, antioxidant defense system, and regulatory genes (Ver-1 and Nor-1) of AFB1 biosynthesis were reported as probable modes of action of NeCn. The NeCn (1.25 µL/mL) effectively protects the P. longum from A. flavus (78.8%), AFB1 contamination (100%), and deterioration of Piperine (62.39%), thus demonstrating its potential as a promising novel antifungal agent for food preservation.

Citronellal: a natural aldehyde with important properties.

Among the several terpenes existing in nature, Citronellal, a monoterpene aldehyde, deserves to be highlighted for its biological properties that have been pointed out in numerous studies. This work aimed to conduct a literature review on its biological properties. Citronellal is a prominent compound in the essential oils of Cymbopogon genus plants. Apart from being employed as a fragrance ingredient in aromas, fragrances, and cosmetics, it is also used as an intermediate in synthesising (-)-menthol. Various studies have demonstrated Citronellal's potential as an antibacterial compound, particularly anti-Staphylococcus and Escherichia bacteria. Citronellal also has antifungal properties against several fungi, especially fungi of the genus Candida. The studies found showed that Citronellal also has insecticidal, acaricidal, antiparasitic, anaesthetic, antiviral, antioxidant, antinociceptive, cardioprotective, antihypertensive, anti-inflammatory, antidiabetic, and anticancer properties.

N-terminal truncation (N-) and directional proton transfer in an old yellow enzyme enables tunable efficient producing (R)- or (S)-citronellal.

(R)-Citronellal is a valuable molecule as the precursor for the industrial synthesis of (-)-menthol, one of the worldwide best-selling compounds in the flavors and fragrances field. However, its biocatalytic production, even from the optically pure substrate (E)-citral, is inherently limited by the activity of Old Yellow Enzyme (OYE). Herein, we rationally designed a different approach to increase the activity of OYE in biocatalytic production. The activity of OYE from Corynebacterium glutamicum (CgOYE) is increased, as well as superior thermal stability and pH tolerance via truncating the different lengths of regions at N-terminal of CgOYE. Next, we converted the truncation mutant N31-CgOYE, a protein involved in proton transfer for the asymmetric hydrogenation of CC bonds, into highly (R)- and (S)-stereoselective enzymes using only three mutations. The mixture of racemic (E/Z)-citral is reduced into the (R)-citronellal with ee and conversion up to 99 % by the mutant of CgOYE, overcoming the problem of the reduction for the mixtures of (E/Z)-citral in biocatalytic reaction. The present work provides a general and effective strategy for improving the activity of OYE, in which the partially conserved histidine residues provide "tunable gating" for the enantioselectivity for both the (R)- and (S)-isomerases.

Anticonvulsant effect of (±) citronellal possibly through the GABAergic and voltage-gated sodium channel receptor interaction pathways: In vivo and in silico studies.

This study aimed to investigate the anticonvulsant effects of citronellal (CIT) and possible underlying mechanisms through an isoniazid (INH)-induced seizure (convulsion) via in vivo and in silico studies. For this, convulsions were induced by the oral administration of INH (300 mg/kg) to the mice. The animals were treated orally with different doses of CIT (50, 100, and 200 mg/kg). Vehicle served as a negative control (NC), while diazepam (DZP) (2 mg/kg) and carbamazepine (CAR) (80 mg/kg) were provided (p.o.) as positive controls (PC). A combination therapy of CIT (middle dose) with DZP and CAR was also given to two separate groups of animals to estimate the synergistic or antagonistic effects. Molecular docking and visualization of ligand-receptor interactions are also estimated through different computational tools. The results of the in vivo study showed that CIT dose-dependently significantly (p < 0.05) exhibited a higher onset of seizures while reducing the frequency and duration of seizures in mice compared to the NC group. Besides these, in combination therapy, CIT significantly antagonized the activity of CAR and DZP, leading to a reduction in the onset of seizures and an increase in their frequency and duration compared to treatment with CAR and DZP alone. Additionally, molecular docking revealed that the CIT exhibited a moderate binding affinity (-5.8 kcal/mol) towards the GABAA receptor and a relative binding affinity (-5.3 kcal/mol) towards the voltage-gated sodium channel receptor by forming several bonds. In conclusion, CIT showed moderate anticonvulsant activity in INH-induced convulsion animals, possibly by enhancing GABAA receptor activity and inhibiting the voltage-gated sodium channel receptor.

Citronellal can alleviate vascular endothelial dysfunction by reducing ectopic miR-133a expression.

AIMS: Endothelial dysfunction (ED) is the initial cause of atherosclerosis (AS) and an early marker of many cardiovascular diseases (CVD). Citronellal (CT), a monoterpenoid natural product extracted from grass plant Citronella, has been shown to have anti-thrombotic, anti-hypertensive and anti-diabetic cardiomyopathy activities. The aim of this study is to investigate the effects of citronellal on vascular endothelial dysfunction and the underlying mechanisms. MATERIALS AND METHODS: The left common carotid artery was subjected to one-time balloon injury to cause vascular endothelial injury, and the AS model was established by feeding with high-fat diet. Use of HUVECs H2O2 treatment induced HUVECs oxidative stress damage model. The blood lipid level, histopathology, Western blot, immunohistochemistry, RT-PCR, ELISA and in situ fluorescence hybridization of common carotid artery tissues and HUVECs were studied. KEY FINDINGS: CT significantly reduced vascular plate area and endothelial lipid and cholesterol deposition in the common carotid artery of mice in a dose-dependent manner. CT increased the expression of activated protein 2α (AP-2α/TFAP2A) and circRNA_102979, and inhibited the ectopic expression level of miR-133a. However, the constructed lentivirus with AP-2α silencing and circRNA_102979 silencing reversed this phenomenon. SIGNIFICANCE: The current study verifies CT can increase the expression levels of AP-2α and circRNA_102979 in vascular endothelium, increase the adsorption effect of circRNA_102979 on miR-133a and relieve the inhibitory effect of miR-133a on target genes, thereby alleviating AS-induced ED.

Antifungal activity of citronellal against Trichophyton rubrum and its predictive mechanism of action by CYP51 inhibition through molecular docking.

The present study aimed to investigate the antifungal activity of citronellal (CIT) against clinical isolates of T. rubrum and to show the possible mechanism of action involved. The antifungal potential of CIT was evaluated from the Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC) and assays with ergosterol and sorbitol, to elucidate the possible mechanisms of action, and molecular docking. MIC and MFC values ranged from 4 to 512 µg/mL. Regarding the mechanism of action, the monoterpene demonstrated interaction with fungal ergosterol. In addition, it is possible to observe that CIT acts on crucial enzymes for the biosynthesis and maintenance of the fungal cell membrane, due to the ability of the monoterpene to bind to CYP51. The results obtained in this research demonstrate that CIT has the potential to become, in the future, a product for the treatment of dermatophytosis.

Citronellal as a Promising Candidate for Alzheimer's Disease Treatment: A Comprehensive Study on In Silico and In Vivo Anti-Acetylcholine Esterase Activity.

One of the primary therapeutic approaches for managing Alzheimer's disease (AD) involves the modulation of Acetylcholine esterase (AChE) activity to elevate acetylcholine (ACh) levels inside the brain. The current study employed computational chemistry approaches to evaluate the inhibitory effects of CTN on AChE. The docking results showed that Citronellal (CTN) and standard Donepezil (DON) have a binding affinity of -6.5 and -9.2 Kcal/mol, respectively, towards AChE. Further studies using molecular dynamics (MD) simulations were carried out on these two compounds. Binding free energy calculations and ligand-protein binding patterns suggested that CTN has a binding affinity of -12.2078. In contrast, DON has a much stronger binding relationship of -47.9969, indicating that the standard DON has a much higher binding affinity than CTN for AChE. In an in vivo study, Alzheimer-type dementia was induced in mice by scopolamine (1.5 mg/kg/day i.p) for 14 days. CTN was administered (25 and 50 mg/kg. i.p) along with scopolamine (SCO) administration. DON (0.5 mg/kg orally) was used as a reference drug. CTN administration significantly improved the mice's behavior as evaluated by the Morris water maze test, evident from decreased escape latency to 65.4%, and in the CPS test, apparent from reduced escape latency to 69.8% compared to the positive control mice. Moreover, CTN significantly increased the activities of antioxidant enzymes such as catalase and superoxide dismutase (SOD) compared to SCO. Furthermore, CTN administration significantly decreased SCO-induced elevated AChE levels in mice. These results were supported by histopathological and in silico molecular docking studies. CTN may be a potential antioxidant and neuroprotective supplement.

Antimicrobial peptides in combination with citronellal efficiently kills multidrug resistance bacteria.

BACKGROUND: Antimicrobial peptides (AMPs) are considered as the most potential alternatives to antibiotics, but they have several drawbacks, including high cost, medium antimicrobial efficacy, poor cell selectivity, which limit clinical application. To overcome the above problems, combination therapy of AMPs with adjuvants might maximize the effectiveness of AMPs. We found that citronellal can substantially potentiate the ZY4R peptide efficacy against Escherichia coli ATCC25922. However, it is unclear whether ZY4R/citronellal combination poses synergistic antimicrobial effects against most bacteria, and their synergy mechanism has not been elucidated. PURPOSE: To investigate synergistic antimicrobial efficacies, biosafety, and synergy mechanism of ZY4R/citronellal combination. METHOD: Checkerboard, time-kill curves, cytotoxicity assays, and in vivo animal models were conducted to assess synergistic antimicrobial effects and biosafety of the ZY4R/citronellal combination. To evaluate their synergy mechanism, a series of cell-based assays and transcriptome analysis were performed. RESULTS: ZY4R/citronellal combination exhibited synergistic antimicrobial effects against 20 clinically significant pathogens, with the fractional inhibitory concentration index (FICI) ranging from 0.313 to 0.047. Meanwhile, ZY4R/citronellal combination enhanced antimicrobial efficacies without compromising cell selectivity, contributing to decreasing drug dosage and improving biosafety. Compared with ZY4R (4 mg/kg) and citronellal (25 mg/kg) alone, ZY4R (4 mg/kg)/citronellal (25 mg/kg) combination significantly decreased the bacterial load in peritoneal fluid, liver, and kidney (P < 0.05) and alleviated pathological damage of the organs of mice. Mechanistic studies showed that ZY4R allowed citronellal to pass through the outer membrane rapidly and acted on the inner membrane together with citronellal, causing more potent membrane damage. The membrane damage prompted the continuous accumulation of citronellal in cells, and citronellal further induced energy breakdown and inhibited exopolysaccharide (EPS) production, which aggravated ZY4R-induced outer membrane damage, thereby resulting in bacterial death. CONCLUSIONS: ZY4R/citronellal combination exhibited broad-spectrum synergy with a low resistance development and high biosafety. Their synergy mechanism acted on two important cellular targets (energy metabolism and membrane integrity). Combination therapy of ZY4R with citronellal may be a promising mixture to combat bacterial infections facing an antibiotic-resistance crisis.

Noxious chemical discrimination by Tribolium castaneum TRPA1 channel in the HEK293 cell expression system.

Nociception is the sensory perception of noxious chemical stimuli. Repellent behavior to avoid noxious stimuli is indispensable for survival, and this mechanism has been evolutionarily conserved across a wide range of species, from mammals to insects. The transient receptor potential ankyrin 1 (TRPA1) channel is one of the most conserved noxious chemical sensors. Here, we describe the heterologous stable expression of Tribolium castaneum TRPA1 (TcTRPA1) in human embryonic kidney (HEK293) cells. The intracellular Ca2+ influx was measured when two compounds, citronellal and l-menthol, derived from plant essential oils, were applied in vitro using a fluorescence assay. The analysis revealed that citronellal evoked Ca2+ influx dose-dependently for TcTRPA1, whereas l-menthol did not. In combination with our present and previous results of the avoidance-behavioral assay at the organism level, we suggest that TcTRPA1 discriminates between these two toxic compounds, and diversification in the chemical nociception selectivity has occurred in TRPA1 channel among insect taxa.

Influence of peeling on volatile and non-volatile compounds responsible for aroma, sensory, and nutrition in ginger (Zingiber officinale).

Industrial use of ginger after peeling results in large amounts of agro-waste. To provide a basic reference for the sustainable processing of ginger products as a spice, we investigated the differences between unpeeled ginger, peeled ginger, and corresponding ginger peel, in terms of aroma, sensory profiles, and nutrition relevant physicochemical properties. The results showed that the total concentrations of identified odor-active compounds in unpeeled ginger, peeled ginger, and ginger peel were 876.56, 672.73, and 105.39 mg/kg, respectively. Unpeeled ginger exhibited more intense citrus-like and fresh impressions compared to peeled ginger, revealed by descriptive sensory analyses. This is relevant to the high odor activity values of odorants such as ß-myrcene (pungent, citrus-like), geranial (citrus-like), citronellal (citrus-like, sourish), and linalool (floral, fresh). In parallel, unpeeled ginger contained higher total polyphenol (84.49 mg/100 g) and total sugar content (33.4 g/kg) in comparison with peeled ginger (76.53 mg/100 g and 28.6 g/kg).

Natural Product Citronellal can Significantly Disturb Chitin Synthesis and Cell Wall Integrity in Magnaporthe oryzae.

BACKGROUND: Natural products are often favored in the study of crop pests and diseases. Previous studies have shown that citronellal has a strong inhibition effect on Magnaporthe oryzae. The objective of this study was to clarify its mechanism of action against M. oryzae. RESULTS: Firstly, the biological activity of citronellal against M. oryzae was determined by direct and indirect methods, and the results show that citronellal had a strong inhibition effect on M. oryzae with EC50 values of 134.00 mg/L and 70.48 µL/L air, respectively. Additionally, a preliminary study on its mechanism of action was studied. After citronellal treatment, electron microscopy revealed that the mycelium became thin and broken; scanning electron microscopy revealed that the mycelium was wrinkled and distorted; and transmission electron microscopy revealed that the mycelium cell wall was invaginated, the mass wall of mycelium was separated, and the organelles were blurred. The mycelium was further stained with CFW, and the nodes were blurred, while the mycelium was almost non-fluorescent after PI staining, and there was no significant difference in the relative conductivity of mycelium. In addition, chitinase was significantly enhanced, and the expression of chitin synthesis-related genes was 17.47-fold upregulated. Finally, we found that the efficacy of citronellal against the rice blast was as high as 82.14% according to indoor efficacy tests. CONCLUSION: These results indicate that citronellal can affect the synthesis of chitin in M. oryzae and damage its cell wall, thereby inhibiting the growth of mycelium and effectively protecting rice from rice blasts.

Citronellal Attenuates Oxidative Stress-Induced Mitochondrial Damage through TRPM2/NHE1 Pathway and Effectively Inhibits Endothelial Dysfunction in Type 2 Diabetes Mellitus.

In type 2 diabetes mellitus (T2DM), oxidative stress induces endothelial dysfunction (ED), which is closely related to the formation of atherosclerosis. However, there are few effective drugs to prevent and cure it. Citronellal (CT) is an aromatic active substance extracted from citronella plants. Recently, CT has been shown to prevent ED, but the underlying mechanism remains unclear. The purpose of this study was to investigate whether CT ameliorated T2DM-induced ED by inhibiting the TRPM2/NHE1 signal pathway. Transient receptor potential channel M2 (TRPM2) is a Ca2+-permeable cation channel activated by oxidative stress, which damages endothelial cell barrier function and further leads to ED or atherosclerosis in T2DM. The Na+/H+ exchanger 1 (NHE1), a transmembrane protein, also plays an important role in ED. Whether TRPM2 and NHE1 are involved in the mechanism of CT improving ED in T2DM still needs further study. Through the evaluations of ophthalmoscope, HE and Oil red staining, vascular function, oxidative stress level, and mitochondrial membrane potential evaluation, we observed that CT not only reduced the formation of lipid deposition but also inhibited ED and suppressed oxidative stress-induced mitochondrial damage in vasculature of T2DM rats. The expressions of NHE1 and TRPM2 was up-regulated in the carotid vessels of T2DM rats; NHE1 expression was also upregulated in endothelial cells with overexpression of TRPM2, but CT reversed the up-regulation of NHE1 in vivo and in vitro. In contrast, CT had no inhibitory effect on the expression of NHE1 in TRPM2 knockout mice. Our study show that CT suppressed the expression of NHE1 and TPRM2, alleviated oxidative stress-induced mitochondrial damage, and imposed a protective effect on ED in T2DM rats.

Lethal concentrations of Cymbopogon nardus essential oils and their main component citronellal on Varroa destructor and Apis mellifera.

Varroosis is a disease caused by the mite Varroa destructor, and it is considered one of the biggest threats to honey bee populations globally. Mite control is centered on the use of synthetic acaricides, such as amitraz and flumethrine. However, high usage of these chemicals is associated with a wide variety of undesirable effects on bee colonies, including the development of resistance and persistence of harmful residues of acaricides in hive products used by humans. Botanical extracts have been identified as a potentially suitable organic alternative to synthetic acaricides. Essential oils, such as clove, eucalyptus, lemongrass, and oregano, have been found to exhibit acaricidal activity against V. destructor. The main goal of this work was to assess the bioactivity of the Cymbopogon nardus essential oil from two different locations (Argentina and India), and the activity of its major component the monoterpene citronellal. According to our results, complete essential oil from India is more effective in controlling parasitosis than the isolated citronellal component. The essential oil of C. nardus from Argentina demonstrated promise for the control of varroosis, as well as exhibiting low toxicity against bees (LC50 = 11.84 µL/mL). In addition, this essential oil may avoid the problems caused by synthetic acaricides, such as the emergence of resistance foci in Varroa and residues in hive products. Future research needs to investigate the delivery of volatile essentials oils to target mite populations.

Effects of citronellal on growth and enterotoxins production in Staphylococcus aureus ATCC 29213.

Staphylococcus aureus (S. aureus) is known to be one of the most common foodborne pathogens capable of secreting a wide range of exotoxins such as enterotoxin, which severely threatens the health of consumers. Over the past few years, the development of safe and effective strategies in inhibiting the growth and enterotoxins generation of S. aureus in food turns out to be the research focus and emphasis. This research explores citronellal (CIT), a native compound with extensive existence in spices, which could effectively inhibit the growth and enterotoxins generation of S. aureus (ATCC 29213). Results from minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curves, showed that CIT could tremendously inhibit the growth of S. aureus. Analysis on hemolysin showed that CIT at sub-MIC could significantly (p < 0.05) inhibit the hemolytic activity of S. aureus. As revealed by the results of ELISA, the production of enterotoxins in the culture supernatant and pork meat decreased significantly (p < 0.05) after exposure to CIT at sub-MIC. Furthermore, a significant (p < 0.05) decrease in dose-dependent was found in the transcription levels of virulence-related genes. In all, CIT proved to be a possible inhibitor of the growth and enterotoxins production of S. aureus with highly promising application in the food industry.

The antifungal and antibiofilm activity of Cymbopogon nardus essential oil and citronellal on clinical strains of Candida albicans.

OBJECTIVE: This study investigated the antifungal and antibiofilm activity of Cymbopogon nardus essential oil (EO) and its major compound, citronellal, in association with miconazole and chlorhexidine on clinical strains of Candida albicans. The likely mechanism(s) of action of C. nardus EO and citronellal was further determined. MATERIALS AND METHODS: The EO was chemically characterized by gas chromatography coupled with mass spectrometry (GC-MS). The antifungal activity (MIC/MFC) and antibiofilm effects of C. nardus EO and citronellal were determined by the microdilution method, and their likely mechanism(s) of action was determined by the sorbitol and ergosterol assays. Then, the samples were tested for a potential association with standard drugs through the checkerboard technique. Miconazole and chlorhexidine were used as positive controls and the assays were performed in triplicate. RESULTS: The GC-MS analysis tentatively identified citronellal as the major compound in C. nardus EO. Both samples showed antifungal activity, with MIC of 256 µg/mL, as compared to 128 µg/mL and 8 µg/mL of miconazole and chlorhexidine, respectively. C. nardus EO and citronellal effectively inhibited biofilm formation (p < 0.05) and disrupted preformed biofilms (p < 0.0001). They most likely interact with the cell membrane, but not the cell wall, and did not present any synergistic activity when associated with standard drugs. CONCLUSION: C. nardus EO and citronellal showed strong in vitro antifungal and antibiofilm activity on C. albicans. CLINICAL RELEVANCE: Natural products have been historically bioprospected for novel solutions to control fungal biofilms. Our data provide relevant insights into the potential of C. nardus EO and citronellal for further clinical testing. However, additional bioavailability and toxicity studies must be carried out before these products can be used for the chemical control of oral biofilms.