A review of six bioactive compounds from preclinical studies as potential breast cancer inhibitors

Breast cancer is one of the predominant causes of mortality in women worldwide. Although therapeutics such as surgery, chemotherapy, hormonal therapy, and radiotherapy have been used, they are associated with adverse effects or multidrug resistance. The use of natural compounds is a promising strategy, owing to their abundance and medicinal value. This review focuses on six natural compounds, namely cinnamaldehyde, diosmin, taxifolin, phloretin, arctigenin, and eugenol, and details their mechanisms of breast cancer inhibition based on in vitro and in vivo studies. These compounds generally promote apoptosis and cell cycle arrest, hinder metastasis and invasion, and decrease tumor growth. This review reinforces the use of natural compounds as therapeutics for breast cancer from their preclinical studies. These compounds might be promising for drug development due to their abundance, high reliability, and safety.

Dose-related effects of eugenol: Exploring renal functionality and morphology in healthy Wistar rats

Eugenol has pharmacological properties, but its impact on renal function is limitedly studied. Thus, this study evaluated the effects of eugenol at 10, 20, and 40 mg kg-1, administered via gavage for 60 days, on histological, biochemical, oxidative, and proteomic parameters in rat kidneys. Adult Wistar rats treated with 10 mg kg-1 of eugenol had kidneys with low total antioxidant capacity, high nitric oxide content, and high percentual of blood vessels, with no damage to renal function or morphology. The kidney proteome revealed an upregulation of proteins associated with energy metabolism, oxidative stress, and mitochondrial function. Eugenol at 20 mg kg-1 did not alter kidney histology but inhibited Na+/K+ ATPase activity. This dose elicited an upregulation of proteins associated with mitochondrial function and cellular defense. Finally, 40 mg kg-1 eugenol had more pronounced effects on the kidney, increasing serum sodium, potassium, and chloride levels, inhibiting Na+/K+ ATPase activity, triggering an adaptive response to oxidative stress, and showing apical brush border thinness in proximal tubules. We concluded that eugenol exerted dose-dependent effects on kidney function and morphology. These findings highlight the importance of careful consideration of eugenol's dosage in therapeutic applications.

Anthocyanin and phenolic landscape of Syzygium cumini extracts via green extraction

This study determined the anthocyanin and phenolic profile of Syzygium cumini bioactive compounds, including anthocyanins and other flavonoids, alongside diverse phenolic compounds. The study optimized a green extraction technique (ultrasound-assisted enzymatic extraction (UAEE)) to obtain anthocyanin-rich extract from the fruit pulp of S. cumini using the pectinase enzyme. UHPLC-LC/MS, FTIR, and SEM were used to profile the secondary metabolites, functional groups, and surface morphology. Two major anthocyanins, cyanidin and malvidin, and twenty-three non-anthocyanins, including gallic acid, naringenin, myricetin, and kaempferol, were identified in the enzymatic extract of S. cumini. A central-composite design was used to optimize the extraction, analyzing the effects of enzyme concentration (0.01-0.03 %), pH (1-3), and ultrasonication time (5-15 min) on total anthocyanin content (438.75 ± 29.81 mg C3G/100 g db), determining the optimal points (0.01 %, 2 pH and 10 mins). The optimized extract was further investigated for total phenolic content and antioxidant activities. The study utilized an economical approach to effectively extract maximum anthocyanins from S. cumini fruit for their potential applications as a biocolorant in food products, simultaneously establishing promising health potential through available literature.

Exploring Natural Deep Eutectic Solvents (NADES) for Enhanced Essential Oil Extraction: Current Insights and Applications

Essential oils (EOs) are highly valued in the cosmetic and food industries for their diverse properties. However, traditional extraction methods often result in low yields, inconsistent compositions, lengthy extraction times, and the use of potentially harmful solvents. Natural deep eutectic solvents (NADES) have emerged as promising alternatives, offering advantages such as higher efficiency, cost-effectiveness, biodegradability, and tunable properties. This review explores the application of NADES in enhancing EO extraction, focusing on current methodologies, key insights, and practical applications. It examines the factors that influence EO extraction with NADES, including the optimization of their physicochemical properties, extraction techniques, operational conditions, and the role of sample pretreatment in improving efficiency. Additionally, this review covers the chemical characterization and biological activities of EOs extracted using NADES. By providing a comprehensive overview, it highlights the potential of NADES to improve EO extraction and suggests directions for future research in this field.

Antibacterial Activity of Selected Essential Oil Components and Their Derivatives: A Review

Essential oils (EOs) are gaining ground and have been intensively studied due to their widespread use in the pharmaceutical, food, and cosmetics industries. The essential components of EOs have been recognized for diverse therapeutic activities and have gained significant attention for their potential antibacterial activities. Despite the popularity of EOs and potent biological properties, their bioactive components and their derivatives are still not comprehensively characterized. This review explores the antibacterial efficacy of selected EO components and their derivatives, focusing on monoterpenes chosen (i.e., carvacrol, menthol, and thymol) and phenylpropanoids (i.e., cinnamaldehyde and eugenol). Furthermore, this review highlights recent advancements in developing derivatives of these EO components, which have shown improved antibacterial activity with reduced toxicity. By summarizing recent studies, this review reveals the potential of these natural compounds and their derivatives as promising candidates for pharmaceuticals, food preservation, and as alternatives to synthetic antibiotics in combating bacterial resistance.

Fats and Oils as a Sustainable Source of Photopolymerizable Monomers

Bio-derived monomers and biobased building blocks obtained from natural sources, e.g., fats and oils, are attracting increasing attention mainly due to sustainability concerns. Due to their features, renewable feedstocks are an excellent alternative to petroleum-based raw materials to shift towards greener chemistry, especially when coupled with energy-efficient processes like photopolymerization. In this review, we illustrate the recent research outcomes in the field of photocurable biobased monomers, showing the advantages of using biobased chemicals for the synthesis of photocurable monomers and the potential of naturally derived building blocks in photocuring reactions.

Waste from the food industry: Innovations in biorefineries for sustainable use of resources and generation of value

Biorefineries have attracted significant attention from the scientific community and various industrial sectors due to their use of unconventional biomass sources to produce biofuels and other value-added compounds. Various agro-industrial residues can be applied in biorefinery systems, making them economically and environmentally attractive. However, the cost, efficiency, and profitability of the process are directly affected by the choice of biomass, pre-treatments, and desired products. In biorefineries, the simultaneous production of different products during processing is a valuable approach. Chemical, physical, biological, or combined treatments can generate numerous compounds of high commercial interest, such as phenolic compounds. These treatments, in addition to modifying the biomass structure, are essential for the process's viability. Over the years, complex treatments with high costs and environmental impacts have been simplified and improved, becoming more specific in generating high-value resources as secondary outputs to the main process (generally related to the release of sugars from lignocelluloses to produce second-generation ethanol). Innovative methods involving microorganisms and enzymes are the most promising in terms of efficiency and lower environmental impact. Biorefineries enable the use of varied raw materials, such as different agro-industrial residues, allowing for more efficient resource utilization and reducing dependence on non-renewable sources. In addition to producing low-carbon biofuels, biorefineries generate a variety of high-value by-products, such as packaging materials, pharmaceuticals, and nutritional ingredients. This not only increases the profitability of biorefineries but also contributes to a circular economy.

Step-by-step synthetic route to access eugenol-1,2,3-triazole-chalcone hybrid

Molecular hybridization represents a strategic approach in drug design, where two or more pharmacophoric elements from distinct bioactive molecules are integrated into a single hybrid compound. In this study, we synthesized hybrid compounds of chalcone, triazole, and eugenol through straightforward reactions using 4-hydroxyacetophenone as the starting material. Initially, 4-hydroxyacetophenone (1) underwent alkylation with 1,4-dibromobutane to produce compound 2 with an 84 % yield. Compound 2 was then subjected to azidation, resulting in azidobutoxyacetophenone 3 with a 71 % yield. Subsequently, compound 3 was reacted with either benzaldehyde or 4-methoxybenzaldehyde via base-catalyzed aldol condensation, yielding azidobutoxychalcones 4a (69 %) and 4b (84 %). Finally, azide-alkyne [3+2] cycloaddition between 4a/4b and propargylated eugenol afforded chalcone derivatives bearing eugenol-1,2,3-triazole hybrids 5a and 5b, each with a 90 % yield.•Synthesized chalcones featuring an eugenol-1,2,3-triazole scaffold using 4-hydroxyacetophenone as the starting material.•Synthesis was accomplished through a four-step reaction sequence.•Products were obtained in good yield.

An antagonist of the neurotransmitter tyramine inhibits the hyperactivating effect of eugenol in the blood-sucking bug, Triatoma infestans

Eugenol is a botanical monoterpene found in the essential oils of several aromatic plants. It has shown to have insecticidal activity, modify insect behavior, and its site of action is most probably in the octopaminergic system. The aim of the present study was to explore whether tyramine receptors are involved in the hyperactivity produced by eugenol in Triatoma infestans, one of the main vectors of Chagas disease. Topical application of tyramine and eugenol increased locomotor activity in third instar nymphs of T. infestans in a dose-dependent way. Yohimbine hydrochloride, a tyramine antagonist, did not modify nymph activity. However, nymphs pretreated with yohimbine and then with tyramine or eugenol showed the same locomotor activity as the controls. Therefore, yohimbine hydrochloride inhibited the hyperactivating effect of both tyramine and eugenol. These results suggest that tyramine receptors are involved in the effect of eugenol on the locomotor activity of T. infestans.

In vitro antimicrobial and antioxidant activities of bioactive compounds extracted from Streptomyces africanus strain E2 isolated from Moroccan soil

This study aimed to isolate Streptomyces sp. from Moroccan terrestrial ecosystems and identify bioactive compounds through GC-MS analysis. Antimicrobial activity was assessed against various pathogenic microorganisms including Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Candida albicans ATCC 60193, and multi-drug resistant strains comprising Listeria monocytogenes, Klebsiella pneumoniae 19K 929, Proteus sp. 19K1313, Klebsiella pneumoniae 20B1572, Proteus vulgaris 16C1737, and Klebsiella pneumoniae 20B1572. Based on the results of the gene sequencing of gene 16S rRNA and phylogenetic analysis, the E2 isolate belongs to the genus Streptomyces with the highest degree of resemblance (97.51%) to the Streptomyces africanus strain NBRC 101005 (NR_112600.1). The isolate exhibited broad-spectrum antibacterial activity, with maximum efficacy against Klebsiella pneumoniae 20B1572 indicated by an inhibition zone diameter of 22.5 ± 0.71mm and a minimum inhibitory concentration (MIC) of 0.0625 mg/mL. The in vitro antioxidant potential of E2 strain was determined through screening of its ethyl acetate extract against sets of antioxidant assays. The results were indicative of E2 strain displaying strong antioxidant activity against ABTS, DPPH free radicals, and FRAP. Furthermore, there was a high significant correlation (p < 0.0001) between the total phenolic and flavonoid content and antioxidant activities. The GC-MS analysis of the extract identified six volatile compounds, with Eugenol (96%) and Maltol (93%) being the most prominent. Additionally, the HPLC-UV/vis analysis revealed six phenolic compounds: gallic acid, chlorogenic acid, vanillic acid, trans-ferulic acid, ellagic acid, and cinnamic acid. Overall, the study highlights Streptomyces sp. strain E2 as a potential source of potent antimicrobial and antioxidant metabolites, offering promise in addressing antibiotic resistance and oxidative stress-related conditions.

Essential Oil and Waste Hydrosol of Ocimum Tenuiflorum L.: A Low-Cost Raw Material Source of Eugenol, Botanical Pesticides, and Therapeutic Potentiality

In this study, essential oils and waste hydrosols of leaves of Ocimum tenuiflorum in four different geographical locations were extracted by hydrodistillation method and using gas chromatography/mass spectrometry (GC/MS) for chemical composition analysis. All four essential oil samples contained the main components (E)-β-caryophyllene (27.8-49.0 %), trans-β-elemene (20.3-37.1 %) and eugenol (9.0-44.0 %). Three of the four hydrosol samples had eugenol in absolute content (94.5-98.6 %), while the remaining hydrosol sample had two main components, elemicin (77.8 %) and eugenol (14.2 %). Essential oils and hydrosols demonstrated larvicidal activities against four important disease-transmitting mosquito species including Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Culex fuscocephala with 24-h LC50 values in the range 15.42-56.01 μg/mL and 53.88-97.80 μg/mL for the essential oils and the hydrosols, respectively. Essential oils and hydrosols strongly inhibited the acetylcholinesterase (AChE) enzyme of electric eels with IC50 values in the range of 25.35-107.19 μg/mL. Microemulsion (ME) can be considered as a sustainable pesticide formulation over 300 days and has improved larvicidal activity compared to free essential oil. The O. tenuiflorum in Vietnam can be considered a low-cost source of eugenol, botanical pesticides that control disease-transmitting mosquitoes, as well as having therapeutic potential to be further investigated.

Potential Involvement of Reactive Oxygen Species in the Bactericidal Activity of Eugenol against Salmonella Typhimurium

There is an increasing need to develop alternative antimicrobials to replace currently used antibiotics. Phytochemicals, such as essential oils, have garnered significant attention in recent years as potential antimicrobials. However, the mechanisms underlying their bactericidal activities are not yet fully understood. In this study, we investigated the bactericidal activity of eugenol oil against Salmonella enterica serovar Typhimurium (S. Typhimurium) to elucidate its mechanism of action. We hypothesized that eugenol exerts its bactericidal effects through the production of reactive oxygen species (ROS), which ultimately leads to cell death. The result of this study demonstrated that the bactericidal activity of eugenol against S. Typhimurium was significantly (p < 0.05) mitigated by thiourea (ROS scavenger) or iron chelator 2,2'-dipyridyl, supporting the hypothesis. This finding contributes to a better understanding of the killing mechanism by eugenol oil.

Synthesis and characterization of nano-biopolymer carriers loaded with clove (Syzygium aromaticum L.) extract as an anticancer agent: an in vitro study

The objective of this work was to design a new drug nanoparticle (NP) composed of chitosan/β-cyclodextrin/sodium tripolyphosphate/alginate (CS/βCD/TPP/AL) loaded with a clove extract (CE) for potential anticancer effects. The extract was prepared by two extraction methods: hydroalcoholic maceration (MAC) with 80% MeOH and supercritical fluid (SCF). The MACCE and SCFCE CE NPs had particle sizes of 71 nm and 20 nm, respectively with irregular spherical shapes. The nanocarriers achieved entrapment efficiencies of over 90%. MACCE-NPs and SCFCE-NPs released 18.35% and 10.12% of the extract after 6 h, respectively. Cell viability decreased to 54%, 7%, and 12% in HeLa, U87, and KB cell lines, respectively, after a 48-hour treatment with SCFCE-NPs and 75%, 8%, and 17% after treatment with MACCE-NPs, significantly reduced compared to the control. It is concluded that NPs containing CE exhibit a higher degree of toxicity due to better penetration into cells.

Microbial transformation of some phytochemicals into value-added products: A review

Phytochemicals, plant-derived compounds, are the major components of traditional medicinal plants. Some phytochemicals have restricted applications, due to low bioavailability and less efficacy. However, their medicinal properties can be enhanced by converting them into value-added products for different bioactivities like anti-oxidant, neuroprotective, anti-obesity, anti-neuroinflammatory, anti-microbial, anti-cancer and anti-inflammatory. Microbial transformation is one such process that is generally more specific and makes it possible to modify a compound without making any unwanted alterations in the molecule. This has led to the efficient production of value-added products with important pharmacological properties and the discovery of new active compounds. The present review assimilates the existing knowledge of the microbial transformation of some phytochemicals like eugenol, curcumin, ursolic acid, cinnamaldehyde, piperine, β-carotene, β-sitosterol, and quercetin to value-added products for their application in food, fragrances, and pharmaceutical industries.

Exploring the Therapeutic Potential of Terpenoids for Depression and Anxiety

This review focus on the terpenoids as potential therapeutic agents for depression and anxiety disorders, which naturally found in a variety of plants and exhibit a wide range of biological activities. Among the terpenoids discussed in this review are α-pinene, β-caryophyllene, α-phellandrene, limonene, β-linalool, 1, 8-cineole, β-pinene, caryophyllene oxide, p-cymene, and eugenol. All of these compounds have been studied extensively regarding their pharmacological properties, such as neuroprotective effect, anti-inflammation, antibacterial, regulation of neurotransmitters and antioxidant effect. Preclinical evidence are reviewed to highlight their diverse mechanisms of action and therapeutic potential to support antidepressant and anxiolytic properties. Additionally, challenges and future directions are also discussed to emphasize therapeutic utility of terpenoids for mental health disorders. Overall, this review provides a promising role of terpenoids as novel therapeutic agents for depression and anxiety, with potential implications for the development of more effective and well-tolerated treatments in the field of psychopharmacology.

Critical review on plant-derived quorum sensing signaling inhibitors in pseudomonas aeruginosa

Pseudomonas aeruginosa, a biofilm-forming organism with complex quorum mechanisms (Las, Rhl, PQS, and IQS), poses an imminent danger to the healthcare sector and renders current treatment options for chemotherapy ineffectual. The pathogen's diverse pathogenicity, antibiotic resistance, and biofilms make it difficult to eradicate it effectively. Quorum sensing, a complex system reliant on cell density, controls P. aeruginosa's pathogenesis. Quorum-sensing genes are key components of P. aeruginosa's pathogenic arsenal, and their expression determines how severe the spread of infection becomes. Over the past ten years, there has been a noticeable increase in the quest for and development of new antimicrobial medications. Quorum sensing may be an effective treatment for infections triggered by bacteria. Introducing quorum-sensing inhibitors as an anti-virulent strategy might be an intriguing therapeutic method that can be effectively employed along with current medications. Amongst the several speculated processes, a unique anti-virulence strategy using anti-quorum sensing and antibiofilm medications for targeting pseudomonal infestations seems to be at the forefront. Due to their noteworthy quorum quenching capabilities, biologically active phytochemicals have become more well-known in the realm of science in this context. Recent research showed how different phytochemical quorum quenching actions affect P. aeruginosa's QS-dependent pathogenicity. This review focuses on the most current data supporting the implementation of plant bio-actives to treat P.aeruginosa-associated diseases, as well as the benefits and future recommendationsof employing them in anti-virulence therapies as a supplementary drug development approach towards conventional antibiotic approaches.

Bioactivity of Eugenol: A Potential Antibiotic Adjuvant with Minimal Ecotoxicological Impact

Combining commercial antibiotics with adjuvants to lower their minimum inhibitory concentration (MIC) is vital in combating antimicrobial resistance. Evaluating the ecotoxicity of such compounds is crucial due to environmental and health risks. Here, eugenol was assessed as an adjuvant for 7 commercial antibiotics against 14 pathogenic bacteria in vitro, also examining its acute ecotoxicity on various soil and water organisms (microbiota, Vibrio fischeri, Daphnia magna, Eisenia foetida, and Allium cepa). Using microdilution methods, checkerboard assays, and kinetic studies, the MICs for eugenol were determined together with the nature of its combinations with antibiotics against bacteria, some unexposed to eugenol previously. The lethal dose for the non-target organisms was also determined, as well as the Average Well Color Development and the Community-Level Physiological Profiling for soil and water microbiota. Our findings indicate that eugenol significantly reduces MICs by 75 to 98%, which means that it could be a potent adjuvant. Ecotoxicological assessments showed eugenol to be less harmful to water and soil microbiota compared to studied antibiotics. While Vibrio fischeri and Daphnia magna were susceptible, Allium cepa and Eisenia foetida were minimally affected. Given that only 0.1% of eugenol is excreted by humans without metabolism, its environmental risk when used with antibiotics appears minimal.

Selective C(aryl)-O bond cleavage in biorenewable phenolics

Biorefining of lignocellulosic biomass via a lignin first approach delivers a range of products with high oxygen content. Besides pulp, a lignin oil rich in guaiacols and syringols is obtained bearing multiple C(aryl)-OH and C(aryl)-OMe groups, typically named phenolics. Similarly, technical lignin can be used but is generally more difficult to process providing lower yields of monomers. Removal of the hydroxy and methoxy groups in these oxygenated arenes is challenging due to the inherently strong C-O bonds, in addition to the steric and electronic deactivation by adjacent -OH or -OMe groups. Moreover, chemoselective removal of a specific group in the presence of other similar functionalities is non-trivial. Other side-reactions such as ring saturation and transalkylation further complicate the desired reduction process. In this overview, three different selective reduction reactions are considered. Complete hydrodeoxygenation removes both hydroxy and methoxy groups resulting in benzene and alkylated derivatives (BTX type products) which is often complicated by overreduction of the arene ring. Hydrodemethoxylation selectively removes methoxy groups in the presence of hydroxy groups leading to phenol products, while hydrodehydroxylation only removes hydroxy groups without cleavage of methoxy groups giving anisole products. Instead of defunctionalization via reduction transformation of C(aryl)-OH, albeit via an initial derivatization into C(aryl)-OX, into other functionalities is possible and also discussed. In addition to methods applying guaiacols and syringols present in lignin oil as model substrates, special attention is given to methods using mixtures of these compounds obtained from wood/technical lignin. Finally, other important aspects of C-O bond activation with respect to green chemistry are discussed.

Role of marination, natural antimicrobial compounds, and packaging on microbiota during storage of chicken tawook

The aim of this study was to investigate the antimicrobial effect of marination, natural antimicrobials, and packaging on the microbial population of chicken tawook during storage at 4°C. Chicken meat was cut into 10 g cubes and marinated. The chicken was then mixed individually with 0.5% or 1% (w/v) vanillin (VA), β-resorcylic acid (BR), or eugenol (EU), and stored under aerobic (AP) or vacuum (VP) packing at 4°C for 7 d. The marinade decreased microbial growth as monitored by total plate count, yeast and mold, lactic acid bacteria, and Pseudomonas spp. by about 1 log cfu/g under AP. The combination of marinade and antimicrobials under AP and VP decreased growth of spoilage-causing microorganisms by 1.5 to 4.8 and 2.3 to 4.6 log cfu/g, respectively. Change in pH in VP meat was less than 0.5 in all treated samples including the control. Marination decreased the lightness of the meat (L*) and significantly (p < 0.05) increased the redness (A*) and yellowness (B*). Overall acceptability was highest for marinated samples with 0.5% BR.

Eco-friendly management strategies of insect pests: long-term performance of rosemary essential oil encapsulated into chitosan and gum Arabic

This study focused on encapsulation of Rosmarinus officinalis essential oil (EO) on chitosan and gum Arabic matrix in various ratios and with varying essential oil concentrations. Additionally, UV/VIS spectroscopy was used to determine cumulative-release profiles. The insecticidal activity was tested against Tribolium castaneum and Oryzaephilus surinamensis, both pests of stored products. In terms of encapsulation efficiency (EE%) and loading capacity (LC%), capsules had EE at 45.8% and LC at 2.31%. Furthermore, many minor compounds were lost after encapsulation, until identifying only 1,8-cineole, α-terpineol, and camphor after 60 d of storage. The fumigant tests demonstrated that encapsulated EO exhibited an effective control against insect pest during storage periods, namely, 30, 45, and 60 d with 99, 66, and 46% mortality for T. castaneum and 100, 84, 82% mortality for O. surinamensis.

Synthesis of eugenol derivative by the ring opening of epoxide eugenol and its analysis through chemical reactivity: a DFT approach

Eugenol, a plant bioactive component, is frequently found in a variety of medicinal plants with well-defined functional attributes. Essential oils containing eugenol were extracted from buds of Eugenia caryophyllata commonly named clove using hydrodistillation. Afterwards, the analysis of the essential oils using gas chromatography/mass spectrometry (GC/MS) shows that eugenol is the major constituent with 70.14% of it. The alkene group in eugenol was epoxidised using m-chloroperbenzoic acid leading to the synthesis of epoxide eugenol. The epoxide ring was cleaved to vanillyl glycol by mixed the epoxide eugenol with aluminum chloride hydrate in an ethanolic medium. A Density Functional Theory (DFT) study was investigated to understand the reactivity of the epoxide eugenol with the aluminum chloride hydrate. The results obtained from DFT based reactivity descriptors were in good agreement with the experiment results.

Atmospheric solids analysis probe mass spectrometry: An easy bolt-on for the synthetic undergraduate teaching laboratory

RATIONALE

High costs and student numbers can often hinder implementation of mass spectrometry (MS) in the undergraduate teaching laboratory, often with technicians running samples on students' behalf, and the implementation of MS only in discrete or isolated experiments. This study explores the use of atmospheric solids analysis probe MS (ASAP-MS) as a relatively low-cost, benchtop instrument, and its potential for application as a 'bolt-on' to existing undergraduate organic chemistry experiments.

METHODS

Thirteen products synthesised in undergraduate laboratory experiments were analysed by ASAP-MS, along with their starting materials. Analysis was carried out with a Waters RADIAN ASAP mass spectrometer, at four different cone voltages simultaneously to provide fragmentation information.

RESULTS

Out of the 13 undergraduate experiments, ASAP-MS was shown to be complementary in 11 of these, either through simple analysis of the precursor ion or by a more complex analysis of the fragments.

CONCLUSIONS

ASAP-MS provided spectra that both complement and enhance intended learning outcomes in existing organic chemistry experiments, showing its versatility as a bolt-on technique. Moving forward, ASAP-MS will be integrated into the University of Surrey's undergraduate teaching laboratory.

In Situ Preparation of Dehydrodieugenol-Loaded Silver Nanoparticles and their Antischistosomal Activity

Schistosomiasis is a major neglected disease that imposes a substantial worldwide health burden, affecting approximately 250 million people globally. As praziquantel is the only available drug to treat schistosomiasis, there is a critical need to identify new anthelmintic compounds, particularly from natural sources. To enhance the activity of different natural products, one potential avenue involves its combination with silver nanoparticles (AgNP). Based on this approach, a one-step green method for the in situ preparation of dehydrodieugenol (DHDG) by oxidation coupling reaction using silver and natural eugenol is presented. AgNP formation was confirmed by UV-Vis spectroscopy due to the appearance of the surface plasmon resonance (SPR) band at 430 nm which is characteristic of silver nanoparticles. The nanoparticles were spherical with sizes in the range of 40 to 50 nm. Bioassays demonstrated that the silver nanoparticles loaded with DHDG exhibited significant anthelmintic activity against Schistosoma mansoni adult worms without toxicity to mammalian cells and an in vivo animal model (Caenorhabditis elegans), contributing to the development of new prototypes based on natural products for the treatment of schistosomiasis.

Antimicrobial Activity of Syzygium aromaticum Essential Oil in Human Health Treatment

The use of natural compounds to prevent and treat infective diseases is increasing its importance, especially in the case of multidrug-resistant (MDR) microorganisms-mediated infections. The drug resistance phenomenon is today a global problem, so it is important to have available substances able to counteract MDR infections. Syzygium aromaticum (L.) Merr. & L.M. Perry (commonly called clove) is a spice characterized by several biological properties. Clove essential oil (EO) consists of numerous active molecules, being eugenol as the principal component; however, other compounds that synergize with each other are responsible for the biological properties of the EO. S. aromaticum is traditionally used for bowel and stomach disorders, cold and flu, oral hygiene, tooth decay, and for its analgesic action. Its EO has shown antioxidant, antimicrobial, anti-inflammatory, neuro-protective, anti-stress, anticancer, and anti-nociceptive activities. This review aims to investigate the role of E. S. aromaticum EO in the counteraction of MDR microorganisms responsible for human disorders, diseases, or infections, such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi, Candida albicans, Giardia lamblia, Streptococcus mutans, Porphyromonas gingivalis, and Klebsiella pneumoniae. This study might orient clinical researchers on future therapeutic uses of S. aromaticum EO in the prevention and treatment of infectious diseases.

Nature stays natural: two novel chemo-enzymatic one-pot cascades for the synthesis of fragrance and flavor aldehydes

Novel synthetic strategies for the production of high-value chemicals based on the 12 principles of green chemistry are highly desired. Herein, we present a proof of concept for two novel chemo-enzymatic one-pot cascades allowing for the production of valuable fragrance and flavor aldehydes. We utilized renewable phenylpropenes, such as eugenol from cloves or estragole from estragon, as starting materials. For the first strategy, Pd-catalyzed isomerization of the allylic double bond and subsequent enzyme-mediated (aromatic dioxygenase, ADO) alkene cleavage were performed to obtain the desired aldehydes. In the second route, the double bond was oxidized to the corresponding ketone via a copper-free Wacker oxidation protocol followed by enzymatic Baeyer-Villiger oxidation (phenylacetone monooxygenase from Thermobifida fusca), esterase-mediated (esterase from Pseudomonas fluorescens, PfeI) hydrolysis and subsequent oxidation of the primary alcohol (alcohol dehydrogenase from Pseudomonas putida, AlkJ) to the respective aldehyde products. Eight different phenylpropene derivatives were subjected to these reaction sequences, allowing for the synthesis of seven aldehydes in up to 55% yield after 4 reaction steps (86% for each step).

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.

Assessment of acute and subacute toxicity, pharmacokinetics, and biodistribution of eugenol nanoparticles after oral exposure in Wistar rats

The present study aimed to assess the safety, toxicity, biodistribution, and pharmacokinetics of eugenol nanoparticles (EONs) following oral administration in Wistar rat models. In the acute toxicity study, the rats were given a fixed dose of 50, 300, and 2000 mg/kg body weight per group orally and screened for 2 weeks after administration. In the subacute study, three different doses (500, 1000, and 2000 mg/kg BW) of EON were administered for 28 days. The results indicated no significant differences in food and water consumption, bodyweight change, hematological and biochemical parameters, relative organ weights, gross findings, or histopathology compared to the control. Additionally, no significant changes were observed in the expression profiles of inflammatory cytokines such as IL-1, IL-6, and TNFα in the plasma, confirming the absence of systemic inflammation. Biodistribution analysis revealed rapid absorption of eugenol and improved bioavailability due to gradual and sustained release, leading to a maximum eugenol concentration of 15.05 μg/mL (Cmax) at approximately 8 h (Tmax) in the blood plasma. Thus, the study provides valuable insights into the utilization of EON for enhancing the stability, solubility, and sustained release of eugenol and highlights its promising safety profile in vivo.

Protective role of eugenol against diabetes-induced oxidative stress, DNA damage, and apoptosis in rat testes

Diabetes mellitus, a metabolic disorder alters gonadal development and spermatogenesis, reactive oxygen species production, DNA damage, and apoptosis, which subsequently lead to male subfertility. Eugenol is an antioxidant, traditionally used as medication for digestive disorders and antioxidant therapy, decrease transport of glucose from GIT to systemic circulation. This experiment was aimed to decipher cellular and molecular insights of eugenol in protecting diabetic germ cells in rats. Rats were assigned randomly into five groups: control, eugenol control (Eugenol 400; EUG), diabetic (DIA), diabetic + eugenol 100 (DIA + EUG 100), and diabetic + eugenol 400 (DIA + EUG 400). EUG 400 and DIA + EUG 400 groups received 400 mg/kg eugenol orally. DIA + EUG 100 group received 100 mg/kg eugenol. Treatment was conducted for 4 weeks. Type 1 diabetes was induced by injecting a single i.p. dose of streptozotocin (55 mg/kg). Morphometric, biochemical, sperm parameters, oxidative stress, hormonal levels, histopathology, and fibrosis in the testis and epididymis, were evaluated. DNA damage was evaluated using halo and comet assays; DNA fragmentation and apoptosis using TUNEL assay. Eugenol treatment significantly normalized biochemical parameters, reduced MDA while increased albumin and GSH levels in diabetes. Eugenol significantly increased sperm numbers, motility and attenuated abnormal sperm head morphology in diabetes. Moreover, eugenol significantly reversed diabetes-induced cellular damages, altered spermatogenesis, and collagen deposition in testis and epididymis. It also significantly attenuated diabetes-associated DNA breaks and apoptosis. These findings suggest that 4 weeks treatment with 400 mg/kg of eugenol could be beneficial for diabetic patients to prevent subfertility.

Catalase associated with antagonistic changes of abscisic acid and gibberellin response, biosynthesis and catabolism is involved in eugenol-inhibited seed germination in rice

KEY MESSAGE

The inhibitory effect of eugenol on rice germination is mediated by a two-step modulatory process: Eugenol first regulates the antagonism of GA and ABA, followed by activation of catalase activity. The natural monoterpene eugenol has been reported to inhibit preharvest sprouting in rice. However, the inhibitory mechanism remains obscure. In this study, simultaneous monitoring of GA and ABA responses by the in vivo GA and ABA-responsive dual-luciferase reporter system showed that eugenol strongly inhibited the GA response after 6 h of imbibition, whereas eugenol significantly enhanced the ABA response after 12 h of imbibition. Gene expression analysis revealed that eugenol significantly induced the ABA biosynthetic genes OsNCED2, OsNCED3, and OsNCED5, but notably suppressed the ABA catabolic genes OsABA8ox1 and OsABA8ox2. Conversely, eugenol inhibited the GA biosynthetic genes OsGA3ox2 and OsGA20ox4 but significantly induced the GA catabolic genes OsGA2ox1 and OsGA2ox3 during imbibition. OsABI4, the key signaling regulator of ABA and GA antagonism, was notably induced before 12 h and suppressed after 24 h by eugenol. Moreover, eugenol markedly reduced the accumulation of H2O2 in seeds after 36 h of imbibition. Further analysis showed that eugenol strongly induced catalase activity, protein accumulation, and the expression of three catalase genes. Most importantly, mitigation of eugenol-inhibited seed germination was found in the catc mutant. These findings indicate that catalase associated with antagonistic changes of ABA and GA is involved in the sequential regulation of eugenol-inhibited seed germination in rice.

The performance of plant essential oils against lactic acid bacteria and adverse microorganisms in silage production

Plant essential oils have played an important role in the field of antibiotic alternatives because of their efficient bacteriostatic and fungistatic activity. As plant essential oils are widely used, their activity to improve the quality of plant silage has also been explored. This review expounds on the active ingredients of essential oils, their bacteriostatic and fungistatic activity, and mechanisms, as well as discusses the application of plant essential oils in plant silage fermentation, to provide a reference for the development and application of plant essential oils as silage additives in plant silage fermentation feed.

Eugenol: In Vitro and In Ovo Assessment to Explore Cytotoxic Effects on Osteosarcoma and Oropharyngeal Cancer Cells

Cancer is a significant health problem worldwide; consequently, new therapeutic alternatives are being investigated, including those found in the vegetable kingdom. Eugenol (Eug) has attracted attention for its therapeutic properties, especially in stomatology. The purpose of this study was to investigate the cytotoxicity of Eug, in vitro, on osteosarcoma (SAOS-2) and oropharyngeal squamous cancer (Detroit-562) cells, as well as its potential irritant effect in ovo at the level of the chorioallantoic membrane (CAM). The data obtained following a 72 h Eug treatment highlighted the reduction in cell viability up to 41% in SAOS-2 cells and up to 37% in Detroit-562 cells, respectively. The apoptotic-like effect of Eug was indicated by the changes in cell morphology and nuclear aspect; the increase in caspase-3/7, -8 and -9 activity; the elevated expression of Bax and Bad genes; and the increase in luminescence signal (indicating phosphatidylserine externalization) that preceded the increase in fluorescence signal (indicating the compromise of membrane integrity). Regarding the vascular effects, slight signs of coagulation and vascular lysis were observed, with an irritation score of 1.69 for Eug 1 mM. Based on these results, the efficiency of Eug in cancer treatment is yet to be clarified.

Nature-Inspired Compounds: Synthesis and Antibacterial Susceptibility Testing of Eugenol Derivatives against H. pylori Strains

The antimicrobial properties of one of the most important secondary metabolites, Eugenol (EU), inspired us to design and synthesize three different series of derivatives enhancing its parent compound's anti-Helicobacter pylori activity. Thus, we prepared semisynthetic derivatives through (A) diazo aryl functionalization, (B) derivatization of the hydroxy group of EU, and (C) elongation of the allyl radical by incorporating a chalcogen atom. The antibacterial evaluation was performed on the reference NCTC 11637 strain and on three drug-resistant clinical isolates and the minimal inhibitory and bactericidal concentrations (MICs and MBCs) highlight the role of chalcogens in enhancing the antimicrobial activity (less than 4 µg/mL for some compounds) of the EU scaffold (32-64 µg/mL).

Therapeutic activity of eugenol towards mitigation of anaemia and oxidative organ damage caused by Plasmodium berghei

The parasite responsible for causing malaria infection, Plasmodium, is known to exhibit resistance to a number of already available treatments. This has prompted the continue search for new antimalarial drugs ranging from medicinal plant parts to synthetic compounds. In lieu of this, the mitigative action of the bioactive compound, eugenol towards P. berghei-induced anaemia and oxidative organ damage was investigated following a demonstration of in vitro and in vivo antiplasmodial effects. Mice were infected with chloroquine-sensitive strain of P. berghei and thereafter treated with eugenol at doses of 10 and 20 mg/kg body weight (BW) for seven days. The packed cell volume and redox sensitive biomarkers in the liver, brain and spleen were measured. Our result demonstrated that eugenol significantly (p < 0.05) ameliorated the P. berghei-associated anaemia at a dose of 10 mg/kg BW. In addition, the compound, at a dose of 10 mg/kg BW, significantly (p < 0.05) alleviated the P. berghei-induced organ damage. This evidently confirmed that eugenol plays an ameliorative role towards P. berghei-related pathological alterations. Hence, the study opens up a new therapeutic use of eugenol against plasmodium parasite.

Fine-Tuning of Ni/NiO over H-NbOx for Enhanced Eugenol Hydrogenation through Enhanced Oxygen Vacancies and Synergistic Participation of Active Sites

The hydrogenation of lignin-derived phenolics to produce valuable chemicals is a promising but challenging task. This study successfully demonstrates the use of sustainable transition metal-based catalysts to hydrogenate lignin-derived phenolics. A defect-induced oxygen vacancy containing H-NbOx prepared from commercial Nb2O5 was employed as a catalyst. H-NbOx exhibited higher oxygen vacancies (158.21 μmol/g) than commercial Nb2O5 (39.01 μmol/g), evaluated from O2-TPD. Upon supporting 10 wt % Ni, a Ni/NiO interface was formed over H-NbOx, which was intrinsically active for the hydrogenation of phenolics. 10Ni/H-NbOx exhibited a two-fold increase in activity than 10Ni/Nb2O5, achieving >99% eugenol conversion and affording ∼94% 4-propyl cyclohexanol selectivity, wherein ∼63% eugenol conversion and ∼73% 4-propyl cyclohexanol selectivity were obtained over 10Ni/Nb2O5. The Ni/NiO formation was confirmed by X-ray photoelectron spectroscopy, HR-TEM, and H2-TPR analysis, while the oxygen vacancies were verified by Raman spectroscopy and O2-TPD analysis. The resulting interface enhanced the synergy between Ni and H-NbOx and facilitated hydrogen dissociation, confirmed by H2-TPD. Remarkably, 10Ni/H-NbOx maintained its catalytic activity for five tested cycles and demonstrated exceptional activity with various phenolics. Our findings highlight the potential of a sustainable transition metal catalyst for the hydrogenation of lignin-derived phenolic compounds, which could pave the path to producing valuable chemicals in an environmentally friendly manner.

A tripartite microbial co-culture system for de novo biosynthesis of diverse plant phenylpropanoids

Plant-derived phenylpropanoids, in particular phenylpropenes, have diverse industrial applications ranging from flavors and fragrances to polymers and pharmaceuticals. Heterologous biosynthesis of these products has the potential to address low, seasonally dependent yields hindering ease of widespread manufacturing. However, previous efforts have been hindered by the inherent pathway promiscuity and the microbial toxicity of key pathway intermediates. Here, in this study, we establish the propensity of a tripartite microbial co-culture to overcome these limitations and demonstrate to our knowledge the first reported de novo phenylpropene production from simple sugar starting materials. After initially designing the system to accumulate eugenol, the platform modularity and downstream enzyme promiscuity was leveraged to quickly create avenues for hydroxychavicol and chavicol production. The consortia was found to be compatible with Engineered Living Material production platforms that allow for reusable, cold-chain-independent distributed manufacturing. This work lays the foundation for further deployment of modular microbial approaches to produce plant secondary metabolites.

Recent advances in bio-based polybenzoxazines as an interesting adhesive coating

Polybenzoxazine (PBz) is an excellent and highly intriguing resin for various sophisticated uses. Benzoxazines have piqued the curiosity of academics worldwide because of their peculiar properties. Nonetheless, most benzoxazine resin manufacturing and processing methods, notably bisphenol A-based benzoxazine, rely on petroleum resources. Because of the environmental consequences, bio-based benzoxazines are being researched as alternatives to petroleum-based benzoxazines. As a result of the environmental implications, bio-based benzoxazines are being developed to replace petroleum-based benzoxazines, and they are gaining traction. Bio-based polybenzoxazine, epoxy, and polysiloxane-based resins have piqued the interest of researchers in coatings, adhesives, and flame-retardant thermosets in recent years due to their anticorrosion, ecologically friendly, affordable, and low water absorption properties. As a result, numerous scientific studies and patents on polybenzoxazine continues to rise in polymer research. Based on its mechanical, thermal, and chemical characteristics, bio-based polybenzoxazine has several applications, including coatings (anticorrosion and antifouling), adhesives (highly crosslinked network, outstanding mechanical and thermal capabilities), and flame retardants (with the high charring capability). This review reports an overview of polybenzoxazine, highlighting the current advances and progress in synthesizing bio-based polybenzoxazine, their properties, and their use in coating applications.

Oleuropein: Chemistry, extraction techniques and nutraceutical perspectives-An update

Olive family (Oleaceae) contains several species among which Olea europaea L. is mostly used for production of olive oils. Various parts of olive tree are rich source of diverse bioactive compounds such as Apigenin, elenolic acid, Hydroxytyrosol, Ligstroside, Oleoside, Oleuropein, Oleuropein aglycone, Tyrosol, etc. Among these, oleuropein, a secoiridoid is predominantly found in olive leaves and young olive fruits of different species of Oleaceae family. Scientists have adopted numerous extraction methods (conventional & latest) to increase the yield of oleuropein. Among these techniques, maceration, soxhlet, microwave-assisted, ultrasonication, and supercritical fluid methods are most commonly employed for extraction of oleuropein. Evidently, this review emphasizes on various in-vitro and in-vivo studies focusing on nutraceutical properties of oleuropein. Available literature highlights the pharmaceutical potential of oleuropein against various diseases such as obesity, diabetes, cardiovascular complications, neurodegenerative diseases, cancer, inflammation, microbial infections, and oxidation. This review will benefit the scientific community as it narrates comprehensive literature regarding absorption, metabolism, bioavailability, extraction techniques, and nutraceutical perspectives associated with oleuropein.

Plausibility of natural immunomodulators in the treatment of COVID-19-A comprehensive analysis and future recommendations

The COVID-19 pandemic has inflicted millions of deaths worldwide. Despite the availability of several vaccines and some special drugs approved for emergency use to prevent or treat this disease still, there is a huge concern regarding their effectiveness, adverse effects, and most importantly, their efficacy against the new variants. A cascade of immune-inflammatory responses is involved with the pathogenesis and severe complications with COVID-19. People with dysfunctional and compromised immune systems display severe complications, including acute respiratory distress syndrome, sepsis, multiple organ failure etc., when they get infected with the SARS-CoV-2 virus. Plant-derived natural immune-suppressant compounds, such as resveratrol, quercetin, curcumin, berberine, luteolin, etc., have been reported to inhibit pro-inflammatory cytokines and chemokines. Therefore, natural products with immunomodulatory and anti-inflammatory potential could be plausible targets to treat this contagious disease. This review aims to delineate the clinical trials status and outcomes of natural compounds with immunomodulatory potential in COVID-19 patients along with the outcomes of their in-vivo studies. In clinical trials several natural immunomodulators resulted in significant improvement of COVID-19 patients by diminishing COVID-19 symptoms such as fever, cough, sore throat, and breathlessness. Most importantly, they reduced the duration of hospitalization and the need for supplemental oxygen therapy, improved clinical outcomes in patients with COVID-19, especially weakness, and eliminated acute lung injury and acute respiratory distress syndrome. This paper also discusses many potent natural immunomodulators yet to undergo clinical trials. In-vivo studies with natural immunomodulators demonstrated reduction of a wide range of proinflammatory cytokines. Natural immunomodulators that were found effective, safe, and well tolerated in small-scale clinical trials are warranted to undergo large-scale trials to be used as drugs to treat COVID-19 infections. Alongside, compounds yet to test clinically must undergo clinical trials to find their effectiveness and safety in the treatment of COVID-19 patients.

A straightforward access to trifluoromethylated natural products through late-stage functionalization

Covering: 2011 to 2021Trifluoromethyl (CF3)-modified natural products have attracted increasing interest due to their magical effect in binding affinity and/or drug metabolism and pharmacokinetic properties. However, the chemo and regioselective construction of natural products (NPs) bearing a CF3 group still remains a long-standing challenge due to the complex chemical scaffolds and diverse reactive sites of NPs. In recent years, the development of late-stage functionalization strategies, including metal catalysis, organocatalysis, light-driven reactions, and electrochemical synthesis, has paved the way for direct trifluoromethylation process. In this review, we summarize the applications of these strategies in the late-stage trifluoromethylation of natural products in the past ten years with particular emphasis on the reaction model of each method. We also discuss the challenges, limitations, and future prospects of this approach.

Multi-Targeting Neuroprotective Effects of Syzygium aromaticum Bud Extracts and Their Key Phytocompounds against Neurodegenerative Diseases

Alzheimer's disease (AD) is a neurodegenerative disease that causes a gradual loss of normal motor and cognitive function. The complex AD pathophysiology involves various factors such as oxidative stress, neuroinflammation, amyloid-beta (Aβ) aggregation, disturbed neurotransmission, and apoptosis. The available drugs suffer from a range of side effects and are not able to cover different aspects of the disease. Therefore, finding a safer therapeutic approach that can affect multiple targets at a time is highly desirable. In the present study, the underlying neuroprotective mechanism of an important culinary spice, Syzygium aromaticum (Clove) extract, and major bioactive compounds were studied in hydrogen peroxide-induced oxidative stress in human neuroblastoma SH-SY5Y cell lines as a model. The extracts were subjected to GC-MS to identify important bioactive components. The extracts and key bio-actives reduced reactive oxygen species (ROS), restored mitochondrial membrane potential (MMP), and provided neuroprotection from H2O2-induced oxidative stress in cell-based assays due to the antioxidant action. They also reduced lipid peroxidation significantly and restored GSH content. Clove extracts have also displayed anti-acetylcholinesterase (AChE) activity, anti-glycation potential, and Aβ aggregation/fibrilization inhibition. The multitarget neuroprotective approach displayed by Clove makes it a potential candidate for AD drug development.

Fighting cytokine storm and immunomodulatory deficiency: By using natural products therapy up to now

A novel coronavirus strain (COVID-19) caused severe illness and mortality worldwide from 31 December 2019 to 21 March 2023. As of this writing, 761,071,826 million cases have been diagnosed worldwide, with 6,879,677 million deaths accorded by WHO organization and has spread to 228 countries. The number of deaths is closely connected to the growth of innate immune cells in the lungs, mainly macrophages, which generate inflammatory cytokines (especially IL-6 and IL-1β) that induce "cytokine storm syndrome" (CSS), multi-organ failure, and death. We focus on promising natural products and their biologically active chemical constituents as potential phytopharmaceuticals that target virus-induced pro-inflammatory cytokines. Successful therapy for this condition is currently rare, and the introduction of an effective vaccine might take months. Blocking viral entrance and replication and regulating humoral and cellular immunity in the uninfected population are the most often employed treatment approaches for viral infections. Unfortunately, no presently FDA-approved medicine can prevent or reduce SARS-CoV-2 access and reproduction. Until now, the most important element in disease severity has been the host's immune response activation or suppression. Several medicines have been adapted for COVID-19 patients, including arbidol, favipiravir, ribavirin, lopinavir, ritonavir, hydroxychloroquine, chloroquine, dexamethasone, and anti-inflammatory pharmaceutical drugs, such as tocilizumab, glucocorticoids, anakinra (IL-1β cytokine inhibition), and siltuximab (IL-6 cytokine inhibition). However, these synthetic medications and therapies have several side effects, including heart failure, permanent retinal damage in the case of hydroxyl-chloroquine, and liver destruction in the case of remdesivir. This review summarizes four strategies for fighting cytokine storms and immunomodulatory deficiency induced by COVID-19 using natural product therapy as a potential therapeutic measure to control cytokine storms.

Nitrocellulose Based Film-Forming Gels with Cinnamon Essential Oil for Covering Surface Wounds

Acute and chronic wounds caused by assorted reasons impact patient's quality of life. Films are one of the main types of moisture retentive dressings for wounds. To improve the healing of the wound, films must ensure there is no microorganism contamination, protect from negative environmental effects, and support optimal moisture content. The aim of this study was to formulate optimal film-forming gel compositions that would have good physico-chemical properties and be suitable for wound treatment. Nitrocellulose, castor oil, ethanol (96%), ethyl acetate, and cinnamon leaf essential oil were used to create formulations. During the study, the drying rate, adhesion, flexibility, tensile strength, cohesiveness, swelling, water vapor penetration, pH value, and morphology properties of films were examined. Results showed that optimal concentrations of nitrocellulose for film-forming gel production were 13.4% and 15%. The concentrations of nitrocellulose and cinnamon leaf essential oil impacted the films' physicochemical properties (drying rate, swelling, adhesion, flexibility, etc.). The swelling test showed that films of formulations could absorb significant amounts of simulant wound exudate. Film-forming gels and films showed no microbial contamination and were stable three months after production.

Spermidine-Eugenol Supplement Preserved Inflammation-Challenged Intestinal Cells by Stimulating Autophagy

Increases in non-communicable and auto-immune diseases, with a shared etiology of defective autophagy and chronic inflammation, have motivated research both on natural products in drug discovery fields and on the interrelationship between autophagy and inflammation. Within this framework, the tolerability and protective effects of a wheat-germ spermidine (SPD) and clove eugenol (EUG) combination supplement (SUPPL) were investigated on inflammation status (after the administration of lipopolysaccharide (LPS)) and on autophagy using human Caco-2 and NCM460 cell lines. In comparison to the LPS treatment alone, the SUPPL + LPS significantly attenuated ROS levels and midkine expression in monocultures, as well as occludin expression and mucus production in reconstituted intestinal equivalents. Over a timeline of 2-4 h, the SUPPL and SUPPL + LPS treatments stimulated autophagy LC3-11 steady state expression and turnover, as well as P62 turnover. After completely blocking autophagy with dorsomorphin, inflammatory midkine was significantly reduced in the SUPPL + LPS treatment in a non-autophagy-dependent manner. After a 24 h timeline, preliminary results showed that mitophagy receptor BNIP3L expression was significantly downregulated in the SUPPL + LPS treatment compared to the LPS alone, whereas conventional autophagy protein expression was significantly higher. The SUPPL shows promise in reducing inflammation and increasing autophagy to improve intestinal health.

Application of Eugenol in Poultry to Control Salmonella Colonization and Spread

The poultry sector is an essential component of agriculture that has experienced unprecedented growth during the last few decades. It is especially true for the United States, where the average intake of chicken meat increased from 10 pounds (4.5 kg) per person in 1940 to 65.2 pounds (29.6 kg) per person in 2018, while the country produced 113 billion eggs in 2019 alone. Besides providing nutrition and contributing significantly to the economy, chicken is also a natural reservoir of Salmonella, which is responsible for salmonellosis in humans, one of the significant foodborne illnesses around the globe. The increasing use of chicken manure and antibiotics increases the spread of Salmonella and selects for multi-drug resistant strains. Various plant extracts, primarily essential oils, have been investigated for their antimicrobial activities. The multiple ways through which these plant-derived compounds exert their antimicrobial effects make the development of resistance against them unlikely. Eugenol, an aromatic oil primarily found in clove and cinnamon, has shown antimicrobial activities against various pathogenic bacteria. A few reports have also highlighted the anti-Salmonella effects of eugenol in chicken, especially in reducing the colonization by Salmonella Enteritidis and Salmonella Typhimurium, the primary Salmonella species responsible for human salmonellosis. Besides limiting Salmonella infection in chicken, the supplementation of eugenol also significantly improves intestinal health, improving overall well-being. In this review, we highlight the rising incidences of salmonellosis worldwide and the factors increasing its prevalence. We then propose the usage of eugenol as a natural feed supplement for containing Salmonella in chicken.

The gut odorant receptor and taste receptor make sense of dietary components: A focus on gut hormone secretion

Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells "smell" and "taste" dietary components and metabolites by taking advantage of chemoreceptors-ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases.

Eugenol promotes appetite through TRP channels mediated-CaMKK2/AMPK signaling pathway

Eugenol is a major component of clove oil. A recent study found that inhalation of eugenol promoted the appetite of mice. However, whether oral ingestion of eugenol promoted appetite is unclear and its mechanism await study. Here, mice were divided into four treatments (n = 20) and fed a basal diet supplemented with 0%, 0.005%, 0.01% and 0.02% eugenol for 4 weeks. In addition, mice (n = 7) were injected intraperitoneally with 3 mg/kg body weight eugenol. Our data showed that feeding mice with 0.01% and 0.02% eugenol promoted their appetite. In addition, the short-term intraperitoneal injection of eugenol enhanced the feed intake in mice within 1 h. Further studies found that dietary eugenol increased orexigenic factors expression and decreased anorexigenic factors expression in mice. We then carried out N38 cell experiments to explore the transient receptor potential (TRP) channels-dependent mechanism of eugenol in promoting appetite. We found that eugenol activated the TRP channels mediated-CaMKK2/AMPK signaling pathway in the hypothalamus and N38 cells. Besides, the inhibition of TRPV1 and AMPK eliminated the upregulation of eugenol on the agouti-related protein level in N38 cells. In conclusion, the study suggested that eugenol promotes appetite through TRPV1 mediated-CaMKK2/AMPK signaling pathway.

4-Allyl-2-methoxyphenol modulates the expression of genes involved in efflux pump, biofilm formation and sterol biosynthesis in azole resistant Aspergillus fumigatus

Introduction

Antifungal therapy for aspergillosis is becoming problematic because of the toxicity of currently available drugs, biofilm formation on host surface, and increasing prevalence of azole resistance in Aspergillus fumigatus. Plants are rich source of bioactive molecules and antimicrobial activity of aromatic bioactive compounds draws attention because of its promising biological properties. The present study elucidated the antibiofilm activity of 4-allyl-2-methoxyphenol (eugenol) against azole-resistant environmental A. fumigatus isolates.

Methods

Soil samples were collected from agricultural fields across India; azole-resistant A. fumigatus (ARAF) were isolated followed by their molecular identification. Antibiofilm activity of eugenol was calculated via tetrazolium based-MTT assay. The expression of the multidrug efflux pumps genes MDR1, MDR4, transporters of the MFS gene, erg11A gene encoding 14α demethylase, and transcription regulatory genes, MedA, SomA and SrbA, involved in biofilm formation of A. fumigatus were calculated by quantitative real time PCR.

Results

Out of 89 A. fumigatus isolates, 10 were identified as azole resistant. Eugenol exhibited antibiofilm activity against ARAF isolates, ranging from 312 to 500 µg/mL. Confocal laser scanning microscopy analysis revealed absence of extracellular matrix of ARAF biofilm after eugenol treatment. The gene expression indicated significantly low expression of efflux pumps genes MDR1, MDR4, erg11A and MedA in eugenol treated ARAF isolates when compared with untreated isolates.

Conclusions

Our results demonstrate that eugenol effects the expression of efflux pump and biofilm associated genes as well as inhibits biofilm formation in azole resistant isolates of A. fumigatus.