Effectiveness and chemical insights: Exploring interactions between nanomicelles and monoterpenoids for head lice treatment.

This study evaluates the pediculicidal activity of nanoformulations containing different binary essential oil component mixtures (eugenol:linalool, 1,8 -cineole:linalool, and eugenol:thymol) using immersion bioassays. These have allowed us to evaluate the knockdown time affecting 50% of the individuals (KT50). In addition, the type of interaction between the components in each mixture was established in terms of the combination index (IC). The KT50 values were 6.07; 8.83; 7.17 and 27.23 h for linalool, 1,8 -cineole, eugenol, and thymol, respectively. For the eugenol:linalool mixtures, the efficacy was lower or equal to that obtained for the nanoformulations of the pure compounds, with values of KT50 about 13.33, 8.16 and 6.71 h for mixtures with ratios 3:1, 1:1 and 1:3, respectively. These mixtures present IC > 1, evidencing antagonistic interaction, which is enhanced with eugenol content. In the case of the binary mixtures of 1,8 -cineole: linalool, KT50 values were similar to those obtained for eugenol:linalool mixtures with similar ratios. In this case, IC assumes values close to unity, suggesting additive interactions independently of the mixture composition. On the other side, mixtures of eugenol:thymol with 1:1 and 1:3 ratios showed values of 9.40 and 32.93 h, while the mixture with a 3:1 ratio showed the greatest effectiveness (KT50 of 4.42 h). Eugenol:thymol mixtures show synergistic interaction (IC < 1) for combinations 3:1 and 1:1, while no interaction was observed for 1:3 combination. This indicates that eugenol enhances thymol activity. These results must be considered an important step forward to the development of effective pediculicidal nanoformulations based on botanical compounds.

Dissolving Hyaluronic Acid-Based Microneedles to Transdermally Deliver Eugenol Combined with Photothermal Therapy for Acne Vulgaris Treatment.

A microneedle transdermal drug delivery system simultaneously avoids systemic toxicity of oral administration and low efficiency of traditional transdermal administration, which is of great significance for acne vulgaris therapy. Herein, eugenol-loaded hyaluronic acid-based dissolving microneedles (E@P-EO-HA MNs) with antibacterial and anti-inflammatory activities are developed for acne vulgaris therapy via eugenol transdermal delivery integrated with photothermal therapy. E@P-EO-HA MNs are pyramid-shaped with a sharp tip and a hollow cavity structure, which possess sufficient mechanical strength to penetrate the stratum corneum of the skin and achieve transdermal delivery, in addition to excellent in vivo biocompatibility. Significantly, E@P-EO-HA MNs show effective photothermal therapy to destroy sebaceous glands and achieve antibacterial activity against deep-seated Propionibacterium acnes (P. acnes) under near-infrared-light irradiation. Moreover, cavity-loaded eugenol is released from rapidly dissolved microneedle bodies to play a sustained antibacterial and anti-inflammatory therapy on the P. acnes infectious wound. E@P-EO-HA MNs based on a synergistic therapeutic strategy combining photothermal therapy and eugenol transdermal administration can significantly alleviate inflammatory response and ultimately facilitate the repair of acne vulgaris. Overall, E@P-EO-HA MNs are expected to be clinically applied as a functional minimally invasive transdermal delivery strategy for superficial skin diseases therapy in skin tissue engineering.

Investigating the Impact of First-Line Anti-Tuberculosis Drugs Encapsulated in a Eugenol-Based Nanoemulsion on Human Serum Albumin.

BACKGROUND: Eugenol exhibits broad-spectrum antibacterial and anti-inflammatory properties. However, cytotoxicity at high concentrations limits the full utilization of eugenol-based drug complexes. Formulations of multidrug-loaded eugenol-based nanoemulsions have reduced cytotoxicity; however, it remains crucial to understand how these eugenol complexes interact with primary human carrier proteins to design and develop therapeutic alternatives. Consequently, this study primarily aims to investigate the impact on Human Serum Albumin (HSA) when it interacts with eugenol-based complexes loaded with first-line anti-tuberculosis drugs. METHODS: This study used various spectroscopic such as UV-visible spectroscopy, Fluorescence spectroscopy, Fourier-transform infrared spectroscopy and computational methods such as molecular docking and 100 ns molecular simulation to understand the impact of eugenol-based first-line anti-tuberculosis drug-loaded nanoemulsions on HSA structure. RESULTS: The binding of the HSA protein and eugenol-based complexes was studied using UV-visible spectroscopic analysis. Minor changes in the fluorophores of the protein further confirmed binding upon interaction with the complexes. The Fourier-transform infrared spectra showed no significant changes in protein structure upon interaction with eugenol-based multidrug-loaded nanoemulsions, suggesting that this complex is safe for internal administration. Unlike eugenol or first-line anti-tuberculosis alone, molecular docking revealed the strength of the binding interactions between the complexes and the protein through hydrogen bonds. The docked complexes were subjected to a 100 ns molecular dynamics simulation, which strongly supported the conclusion that the structure and stability of the protein were not compromised by the interaction. CONCLUSIONS: From the results we could comprehend that the eugenol (EUG)-drug complex showed greater stability in HSA protein structure when compared to HSA interacting with isoniazid (INH), rifampicin (RIF), pyrazinamide (PYR), or ethambutol (ETH) alone or with EUG alone. Thus, inferring the potential of EUG-based drug-loaded formulations for a safer and efficient therapeutic use.

Pickering nanoemulsion loaded with eugenol contributed to the improvement of konjac glucomannan film performance.

Konjac glucomannan (KGM) is becoming a very potential food packaging material due to its good film-forming properties and stability. However, KGM film has several shortcomings such as low mechanical strength, strong water absorption, and poor self-antibacterial performance, which limits its application. Therefore, in order to enhance the mechanical and functional properties of KGM film, this study prepared Pickering nanoemulsion loaded with eugenol and added it to the KGM matrix to explore the improvement effect of Pickering nanoemulsion on KGM film properties. Compared to pure KGM film and eugenol directly added film, the mechanical strength of Pickering-KGM film was significantly improved due to the establishment of ample hydrogen bonding interactions between the ß-cyclodextrin inclusion complex system and KGM. Pickering-KGM film had significant antioxidant capacity than pure KGM film and eugenol directly added KGM film (eugenol-KGM film) (~3.21 times better than KGM film, ~0.51 times better than eugenol-KGM film). In terms of antibacterial activity, Pickering-KGM film had good inhibitory effect on Escherichia coli, Staphylococcus aureus, and Candida albicans, and raspberry preservation experiment showed that the shelf life of the Pickering-KGM film could be extended to about 6 days. To sum up, this study developed a novel means to improve the film performance and provide a new insight for the development and application of food packaging film.

A Promising Plant-Based Eugenol-Loaded Nano Delivery System (EUG@CMC-PGMA-CS) for Enhanced Antibacterial and Insect Repellent Behavior.

Pathogens and pests pose significant threats to global crop productivity and plant immunity, necessitating urgent measures from researchers to prevent pathogen contamination and pest damage to crops. A natural plant-based antibacterial agent, eugenol (EUG), has demonstrated excellent antimicrobial and insect repellent capabilities, but the characteristics of volatilization and poor dissolution limit the practical application. The nanoization of pesticide formulations holds promise in the development of highly effective pesticides for antibacterial and insecticidal purposes. Herein, a eugenol-loaded nano delivery system (EUG@CMC-PGMA-CS) was synthesized using glycidyl methacrylate (GMA) as a functional monomer to connect carrier core structure carboxymethyl cellulose (CMC) with shell structure chitosan (CS), and EUG was encapsulated within the carrier. EUG@CMC-PGMA-CS demonstrated excellent leaf affinity, with minimum contact angles (CAs) of 37.83 and 70.52° on hydrophilic and hydrophobic vegetable leaf surfaces, respectively. Moreover, the maximum liquid holding capacity (LHC) of EUG@CMC-PGMA-CS on both hydrophilic and hydrophobic vegetable leaf surfaces demonstrates a noteworthy 55.24% enhancement compared to the LHC of pure EUG. The in vitro release curve of EUG@CMC-PGMA-CS exhibited an initial burst followed by stable sustained release. It is with satisfaction that the nano delivery system demonstrated exceptional antibacterial properties against S. aureus and satisfactory insecticidal efficacy against Spodoptera litura. The development of this eugenol-loaded nano delivery system holds significant potential for enhanced antibacterial and insect repellents in agriculture, paving the way for the application of volatile bioactive substances.

Pharmacodynamic, pharmacokinetic, toxicity, and recent advances in Eugenol's potential benefits against natural and chemical noxious agents: A mechanistic review.

The active biological phytochemicals, crucial compounds employed in creating hundreds of medications, are derived from valuable and medicinally significant plants. These phytochemicals offer excellent protection from various illnesses, including inflammatory disorders and chronic conditions caused by oxidative stress. A phenolic monoterpenoid known as eugenol (EUG), it is typically found in the essential oils of many plant species from the Myristicaceae, Myrtaceae, Lamiaceae, and Lauraceae families. One of the main ingredients of clove oil (Syzygium aromaticum (L.), Myrtaceae), it has several applications in industry, including flavoring food, pharmaceutics, dentistry, agriculture, and cosmeceuticals. Due to its excellent potential for avoiding many chronic illnesses, it has lately attracted attention. EUG has been classified as a nonmutant, generally acknowledged as a safe (GRAS) chemical by the World Health Organization (WHO). According to the existing research, EUG possesses notable anti-inflammatory, antioxidant, analgesic, antibacterial, antispasmodic, and apoptosis-promoting properties, which have lately gained attention for its ability to control chronic inflammation, oxidative stress, and mitochondrial malfunction and dramatically impact human wellness. The purpose of this review is to evaluate the scientific evidence from the most significant research studies that have been published regarding the protective role and detoxifying effects of EUG against a wide range of toxins, including biological and chemical toxins, as well as different drugs and pesticides that produce a variety of toxicities, throughout view of the possible advantages of EUG.

pH-responsive on-demand release of eugenol from metal-organic frameworks for synergistic bacterial killing.

Bacterial infections are a big challenge in clinical treatment, making it urgent to develop innovative antibacterial systems and therapies to combat bacterial infections. In this study, we developed a novel MOF-based synergistic antibacterial system (Eu@B-UiO-66/Zn) by loading a natural antibacterial substance (eugenol) with hierarchically porous MOF B-UiO-66 as a carrier and further complexing it with divalent zinc ions. Results indicate that the system achieved a controlled release of eugenol under pH responsive stimulation, with the complexation ability of eugenol and Zn2+ ions as a switch. Due to the destruction of a coordination bond between eugenol and Zn2+ ions by an acidic medium, the release of eugenol loaded in Eu@B-UiO-66/Zn reached 80% at pH 5.8, which was significantly higher than that under pH 8.0 (51%). Moreover, the inhibitory effect of Eu@B-UiO-66/Zn against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) after 24 h was 96.4% and 99.7%, respectively, owing to the synergistic antibacterial effect of eugenol and Zn2+ ions, which was significantly stronger than free eugenol and Eu@B-UiO-66. We hope that this strategy for constructing responsive MOF-based antibacterial carriers could have potential possibilities for the application of MOF materials in antibacterial fields.

Succinylated starch emulsified Eugenol and Carvacrol nanoemulsions improved digestive stability, bio-accessibility and Salmonella typhimurium inhibition.

The ultrasonically processed Eugenol (EU) and Carvacrol (CAR) nanoemulsions (NE) were successfully optimized via response surface methodology (RSM) to achieve broad spectrum antimicrobial efficacy. These NE were prepared using 2 % (w/w) purity gum ultra (i.e., succinylated starch), 10 % (v/v) oil phase, 80 % (800 W) sonication power, and 10 min of processing time as determined via RSM. The second order Polynomial method was suitable to RSM with a co-efficient of determination >0.90 and a narrow polydispersity index (PDI) ranging 0.12-0.19. NE had small droplet sizes (135.5-160 nm) and low volatility at high temperatures. The EU & CAR entrapment and heat stability (300 °C) confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Further, the volatility of EU & CAR NE was 18.18 ± 0.13 % and 12.29 ± 0.11 % respectively, being lower than that of bulk/unencapsulated EU & CAR (i.e., 23.48 ± 0.38 % and 19.11 ± 0.08 %) after 2 h at 90 °C. Interestingly, both EU & CAR NE showed sustained release behaviour till 48 h. Their digest could inhibit Salmonella typhimurium (S. typhimurium) via membrane disruption and access to cellular machinery as evident from SEM images. Furthermore, in-vivo bio-accessibility of EU & CAR in mice serum was up to 80 %. These cost-effective and short-processed EU/CAR NE have the potential as green preservatives for food industry.

Self-assembly of sophorolipid and eugenol into stable nanoemulsions for synergetic antibacterial properties through alerting membrane integrity.

Exploring the natural, safe, and effective antimicrobial is one of the preferable ways to control foodborne bacteria. In this work, novel oil-in-water nanoemulsions were formulated with sophorolipids and eugenol without any co-surfactant using a self-assembling strategy. These nanoemulsions showed high stability with sizes less than 200 nm when exposure to low concentrations of salt ions, various pH values (5.0, 7.0, 10.0), storage temperature and time. The synergistic antibacterial effects against both Gram-negative Escherichia coli and Gram-positive Bacillus cereus were determined with a minimum inhibitory concentration (MIC) value of 0.5 mg/mL and 0.125 mg/mL, respectively. Further microscopy (SEM, TEM, LCSM) examination and ATP/Na+-K+-ATPase assay results showed that the morphological changes, intensive cell membrane permeability, leakage of ATP, and decreased Na+-K+-ATPase contributed to the antibacterial effects. Moreover, the bonding mechanism between nanoemulsions and cell membranes were further evaluated by FTIR and ITC using a DPPC vesicle model, which demonstrated that the nanoemulsions adsorbed on the surface of bilayer, interacted with the hydrophobic chains of DPPC membrane mainly through the hydrophobic interaction, and altered the structural integrity of the lipid bilayer. These results not only provide a facile green strategy for fabricating stable nanoemulsions, but also highlight a new perspective for stabilizing essential oils for their widely application in food industry.

Salting-out effect-mediated size-control of protein nanoparticles towards controllable microstructures for sustained release of eugenol.

Size and monodispersity of solid particles are essential to their structuring behaviors at biphasic interfaces. However, delicate control over biomolecular nanoparticle sizes is challenging. In this study, we prepared monodisperse rice protein (RP) nanoparticles by neutralizing RP solutions (pH 12.0) using combined treatments of cationic exchange resins (CERs) and HCl. CERs absorbed Na+ by releasing H+ without producing salt during neutralization. By compromising the usages of CERs and HCl when preparing RPs, the generation of NaCl can be delicately tailored, leading to controllable nanoparticle sizes from 20 nm to 30 nm. By mixing these nanoparticles with eugenol in an aqueous solution, the nanoparticles accommodated eugenol in their cores due to inward diffusion. Furthermore, such eugenol-contained nanoparticles with different sizes demonstrated tunable releases of eugenol due to size-dependent capillary forces, which can be harnessed for suppression of microbial growth on fruit with prolonged effective eugenol concentration.

Antioxidant Capacity of Eugenol and Its Effect on Intestinal Flora Under in Vitro Simulated Conditions.

In northern China, clove is a common plant. Its extracted eugenol exhibits a variety of biological properties, including antioxidant and antibacterial effects. This study looked at eugenol's antioxidant potential and its impact on the flora in the intestinal tract of humans. Eugenol's ability to scavenge superoxide anions and 2,2-biphenyl-1-picrylhydrazyl (DPPH) radicals, as well as its impact on the growth of common intestinal bacteria Lactobacillus and Escherichia coli, were studied at various eugenol concentrations. The results showed that different optimal antioxidant concentrations of eugenol existed for different free radicals, and the optimal antioxidant concentrations for DPPH and superoxide anion were 0.16 µL/mL and 0.04 µL/mL, respectively. Low concentrations of eugenol had no significant inhibitory effect on Lactobacillus but a significant inhibitory effect on E. coli. This research is anticipated to offer a theoretical reference for the use of eugenol in specialized dietary food applications.

DNA binding peptide CF-14 enhances bactericidal efficacy of eugenol/carvacrol nanoparticles to Escherichia coli.

To evaluate the bactericidal action of antimicrobial peptide CF-14, Eugenol (EU) and carvacrol (CAR) nanoparticles (NPs) less than 200 nm were surface-modified with CF14, gaining approximately 200 nm of EU-CF and CAR-CF NPs with swollen morphology. EU-CF and CAR-CF NPs were bactericidal to E. coli at dosage of 0.09% and 0.07% (v/v), respectively; while they were just bacteriostatic to Staphylococcus aureus at 0.10% and 0.08% (v/v). Spectral variations in bacterial carbohydrates (1185-900 cm-1), lipids (3000-2800 cm-1) and DNA (1500-1185 cm-1) were obvious as evident from Fourier transform infrared spectroscopy (FTIR). A higher percentage of membrane damaged (non-revivable) E. coli than S. aureus was found, which indicated electrostatic interactions between Gram-negative E. coli with cationic CF conjugated NPs leading to DNA disintegration. Interestingly, EU-CF and CAR-CF NPs inhibited E. coli growth in orange juice without impacting flavour compounds.

New miconazole-based azoles derived from eugenol show activity against Candida spp. and Cryptococcus gattii by inhibiting the fungal ergosterol biosynthesis.

This work describes the design, synthesis and antifungal activity of new imidazoles and 1,2,4-triazoles derived from eugenol and dihydroeugenol. These new compounds were fully characterized by spectroscopy/spectrometric analyses and the imidazoles 9, 10, 13 e 14 showed relevant antifungal activity against Candida sp. and Cryptococcus gattii in the range of 4.6-75.3 µM. Although no compound has shown a broad spectrum of antifungal activity against all evaluated strains, some azoles were more active than either reference drugs employed against specific strains. Eugenol-imidazole 13 was the most promising azole (MIC: 4.6 µM) against Candida albicans being 32 times more potent than miconazole (MIC: 150.2 µM) with no relevant cytotoxicity (selectivity index >28). Notably, dihydroeugenol-imidazole 14 was twice as potent (MIC: 36.4 µM) as miconazole (MIC: 74.9 µM) and more than 5 times more active than fluconazole (MIC: 209.0 µM) against alarming multi-resistant Candida auris. Furthermore, in vitro assays showed that most active compounds 10 and 13 altered the fungal ergosterol biosynthesis, reducing its content as fluconazole does, suggesting the enzyme lanosterol 14α-demethylase (CYP51) as a possible target for these new compounds. Docking studies with CYP51 revealed an interaction between the imidazole ring of the active substances with the heme group, as well as insertion of the chlorinated ring into a hydrophobic cavity at the binding site, consistent with the behavior observed with control drugs miconazole and fluconazole. The increase of azoles-resistant isolates of Candida species and the impact that C. auris has had on hospitals around the world reinforces the importance of discovery of azoles 9, 10, 13 e 14 as new bioactive compounds for further chemical optimization to afford new clinically antifungal agents.

In Vitro Antiviral Potential, Antioxidant, and Chemical Composition of Clove (Syzygium aromaticum) Essential Oil.

Viral infections are spread all around the world. Although there are available therapies, their safety and effectiveness are constrained by their adverse effects and drug resistance. Therefore, new natural antivirals have been used such as essential oils, which are natural products with promising biological activity. Accordingly, the present study aimed to identify the components of clove (Syzygium aromaticum) essential oil (EOCa) and verify its antioxidant and antiviral activity. The oil was analyzed using GC/MS, and the antioxidant capacity was evaluated as a function of the radical scavenging activity. A plaque reduction test was used to measure the antiviral activity against herpes simplex virus (HSV-1), hepatitis A virus (HAV), and an adenovirus. GC/MS analysis confirmed the presence of eugenol as the main component (76.78%). Moreover, EOCa had powerful antioxidant activity with an IC50 of 50 µg/mL. The highest antiviral potential was found against HAV, with a selectivity index (SI) of 14.46, while showing poor selectivity toward HSV-1 with an SI value of 1.44. However, no relevant effect was detected against the adenovirus. The antiviral activity against HAV revealed that its effect was not related to host cytotoxicity. The findings imply that EOCa can be utilized to treat diseases caused by infections and free radicals.

Antibacterial Potent of Acetylated and Non-Acetylated Clove Bud Essential Oils and Their Main Compounds.

Clove bud is a medicinal plant used traditionally in Asia for the treatment of various disease. Previously, Clove oil is a potential source of an antimicrobial compounds especially vis-a-vis bacterial pathogens. However, the compound responsible for this activity remains to be investigated. Essential oil (EO) clove, acetylated essential oil clove, eugenol, and acetyleugenol were evaluate as an antibacterial potential agent against Staphyloccocus aureus (SE), Escherichia coli (EC) and Pseudomonas aeruginosa (PA). Essential oil containing eugenol was extracted from buds of Eugenia caryophyllata commonly named clove (Syzygium aromaticum (L.) (Family Myrtaceae) by a simple hydrodistillation. The analysis of the essential oils (EOs) using gas chromatography-mass spectrometry (GC-MS) shows eugenol as the major constituent with 70.14 % of the total. The Eugenol was isolated from the EO using chemical treatment. Afterwards, the EO and eugenol were converted to acetylated EO and acetyleugenol, respectively using acetic anhydride. The antibacterial result revealed that all compounds showed a strong activity against the three strains. The Staphyloccocus aureus and Pseudomonas aeruginosa were extremely sensitive against eugenol with an inhibition diameters of 25 mm. The MIC values of eugenol versus S. aureus and P. aeruginosa were 0.58 and 2.32 mg/mL, respectively, while the MIB values were 2.32 mg/mL and 9.28 mg/mL.

Investigation of the effects of isoeugenol-based phenolic compounds on migration and proliferation of HT29 colon cancer cells at cellular and molecular level.

Colorectal cancer is a type of cancer encountered worldwide and ranks third among all cancer types in terms of incidence. Polyphenols have been shown to have a wide range of biological functions, including a significant impact on cancer start, development, and promotion through regulating many signaling pathways. The aim of this study was to investigate the anticancer effects of isoeugenol based compounds 1, 2 on HT29 colorectal cancer cell line in vitro. MTT test and scratch assay were carried out to determine the effect of these compounds on HT29 cell proliferation and migration respectively. In addition, mRNA expression levels of apoptosis and metastasis-related genes (p53, Bcl2, Bax, Caspase 3, Caspase7, Caspase8, Caspase9, HIF1-α, VEGF, MMP-2, MMP-9) were examined by quantitative real-time PCR. The results indicated that 1 and 2 inhibited HT29 cell proliferation and induced apoptosis by increasing the Bax/Bcl2 ratio and Caspase-9 and Caspase-3 mRNA expression. In conclusion, the results of this study showed that the treatment of these compounds significantly suppressed the mRNA expressions of metastasis-related genes such as Matrix Metalloproteinase-2, Matrix Metalloproteinase-9, Vascular Endothelial Growth Factor and Hypoxia­Inducible Factor 1α.

The selective encapsulation and stabilization of cinnamaldehyde and eugenol in high internal phase Pickering emulsions: Regulating the interfacial properties.

This work aimed to investigate the encapsulation and stabilization mechanism of cinnamaldehyde and eugenol in high internal phase Pickering emulsions (HIPPEs) through regulating their interfacial rheological properties and interfacial microstructure. With the incorporation of cinnamaldehyde, the Schiff base reaction between the cinnamaldehyde and proteins favored the formation of the predominantly elastic and solid-like interfacial layers. In contrast, the hydrogen bonds between eugenol and proteins resulted in the transformation of interfacial layers to viscous dominant with weak viscoelastic responses. Thus, cinnamaldehyde-loaded HIPPEs had a better storage stability than eugenol-loaded HIPPEs, and the retention rate was increased by about 15 %∼20 %. The addition of tea camellia seed oil inhibited the mobility of immobilized water and improved the retention rates of cinnamaldehyde and eugenol by approximately 6 % and 12 % (30 days at 25 °C), respectively. These findings will be beneficial for the development and design of effective essential oil encapsulation systems in the food industry.

Biotransformation of eugenol by an endophytic fungus Daldinia sp. IIIMF4010 isolated from Rosmarinus officinalis.

Natural value-added compounds produced from biological sources have attained immense significance in medicinal, food, flavourings, and agrochemical industries. Further, biotransformation is a powerful tool used to produce value-added compounds cost-effectively and selectively. In the present study, biotransformation of eugenol using an endophytic fungus Daldinia sp. IIIMF4010 isolated from the fresh leaves of the plant Rosmarinus officinalis leads to the production of two known value-added compounds. The biotransformation reaction of eugenol (50 mM) resulted in the production of eugenol-ß-D-glucopyranoside (6.2%) and vanillin (21.8%). These biotransformed products were further characterized by liquid chromatography-mass spectroscopy (LC-MS) and nuclear magnetic resonance (NMR).

A Comprehensive in vitro and in silico Assessment on Inhibition of CYP51B and Ergosterol Biosynthesis by Eugenol in Rhizopus oryzae.

Mucormycosis, also known as Zygomycosis, is a disease caused by invasive fungi, predominantly Rhizopus species belonging to the Order of Mucorales. Seeing from the chemistry perspective, heterocyclic compounds with an "azole" moiety are widely employed as antifungal agent for minimising the effect of mucormycosis as a prescribed treatment. These azoles serve as non-competitive inhibitors of fungal CYP51B by predominantly binding to its heme moiety, rendering its inhibition. However, long-term usage and abuse of azoles as antifungal medicines has resulted in drug resistance among certain fungal pathogens. Hence, there is an unmet need to find alternative therapeutic compounds. In present study, we used various in vitro tests to investigate the antifungal activity of eugenol against R. oryzae/R. arrhizus, including ergosterol quantification to test inhibition of ergosterol production mediated antifungal action. The minimum inhibitory concentration (MIC) value obtained for eugenol was 512 µg/ml with reduced ergosterol concentration of 77.11 ± 3.25% at MIC/2 concentration. Further, the molecular interactions of eugenol with fungal CYP51B were meticulously studied making use of proteomics in silico study including molecular docking and molecular dynamics simulations that showed eugenol to be strongly interacting with heme in an identical fashion to that shown by azole drugs (in this case, clotrimazole was evaluated). This is the first of a kind study showing the simulation study of eugenol with CYP51B of fungi. This inhibition results in ergosterol synthesis and is also studied and compared with keeping clotrimazole as a reference.

Potential dual inhibition of SE and CYP51 by eugenol conferring inhibition of Candida albicans: Computationally curated study with experimental validation.

Ergosterol is the key sterol component in the cell membrane of fungi including moulds and yeasts. Any decrease in the levels of ergosterol in the cell membrane of fungi render them venerable to cell membrane damage and even its death. Majority of antifungal drug targets the key enzymes involved in ergosterol biosynthesis pathway. The biochemical pathway for the synthesis of Ergosterol is a complex one, though the reactions carried by Squalene Epoxidase (SE) and 14α-demethylase (CYP51- a member of Cytochrome P450 family) serves to the key rate limiting reactions that can impact the overall production of Ergosterol. Allylamines class of antifungal drug target SE while Azoles target the CYP51. Currently advancement in the drug development is focused to introduce newer drugs that can simultaneously inhibit both this rate limiting enzymes. However, natural compounds established to possess antifungal activity but the major loophole about their understanding lies in the fact that their mode of action are severely unstudied. One such well-established antifungal natural phytochemical is Eugenol, and in current manuscript we investigated its efficacy to interact with both, SE and CYP51 of Candida albicans using molecular Docking, Free energy change calculations and Molecular Dynamics (MD) simulation, showing promising outcomes. For experimental studies, terbinafine, clotrimazole and eugenol showed 4 µg/ml, 2 µg/ml, and 512 µg/ml MIC90 values, respectively against C. albicans and also showed reduction in Ergosterol production at sub-MIC levels. The obtained result indicates the involvement of eugenol in the inhibition of enzymes require in the ergosterol biosynthesis pathway.