Syzygium aromaticum L.: phytochemical investigation and comparison of the scavenging activity of essential oil, extracts and eugenol

Clove Buds Volatile Compounds: Inhibitory Activity on Mycobacterium Growth and Molecular Docking on Mmr Efflux Pump Drug Resistance

Syzygium aromaticum is used in traditional and modern medicine for its various and outstanding pharmacological properties. Here, we studied the chemical composition of hexane extract and non-polar fractions (NPF) obtained from the maceration and fractionation of clove buds, in order to evaluate their in vitro antimycobacterial activity, as well as their contribution against efflux pump (EP) resistance through molecular docking experiments. The gas chromatography-mass spectrometry (GC-MS) analysis of the volatile profiles revealed the presence of eugenol, followed by eugenyl acetate, and β-caryophyllene as common major compounds. According to Resazurin microtiter assay (REMA), Mycobacterium tuberculosis H37 Rv strain was sensitive to all volatile samples at concentration range between 10 and 100 μg/mL. The NPF of ethanol extract was the best inhibitor with a MIC=10 μg/mL. The in silico study revealed a strong binding affinity between eugenol and Mmr EP protein (-8.1 Kcal/mol), involving two binding modes of hydrogen bond and π-alkyl interactions. The non-polarity character of clove volatile constituents, and their potential additive or synergistic effects could be responsible for the antimycobacterial activity. In addition, these findings suggest the benefic effect of eugenol in the management of mycobacterium drug resistance, whether as potential inhibitor of Mmr drug EP, or modulator during combination therapy.

Bioactivity of the Ethanol Extract of Clove (Syzygium aromaticum) as Antitoxin

Toxic compounds can induce the formation of free radicals (reactive oxygen species (ROS)) which can trigger damage and decrease cell viability. Clove (Syzygium aromaticum) contains phenolic compounds that are useful as antioxidants which can reduce ROS toxicity. However, little is known about the antitoxin activity of clove extract. Therefore, this study is aimed at determining the effect of ethanolic clove extract as an antitoxin agent against malachite green (MG) mutagen using the yeast Saccharomyces cerevisiae as a model. The methods used to analyze the ability of ethanolic clove extract as antitoxin were decolorization assay and cell viability test towards MG. The phenol contents of leaf and bud extract were 441.28 and 394.73 mg GAE g-1 extract, respectively. Clove leaf extract has strong antioxidant activity in vitro (IC50 9.29 ppm for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 29.57 for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)). Liquid chromatography quadrupole-mass spectrometry (LC-MS/MS) analysis showed the presence of 4-O-caffeoylquinic acid and several other bioactive compounds, in which these compounds had bioactivity against toxic compound. The addition of extract reduced the ability of S. cerevisiae to decolorize malachite green but increased cell viability. Based on the data, clove leaf extract shows the potential antitoxin activity. This research should facilitate a preliminary study to investigate the antitoxin agent derived from cloves leaf extract. Further research to analyze the antitoxin mechanism of this extract in yeast model is interesting to do to provide a comprehensive insight into the potential antitoxin agents of clove leaf extract.

Antibacterial, antioxidant, and cytotoxic activities of Syzygium aromaticum (L.) Merr. & Perry essential oil with identification of its chemical constituents

Aromatic plants embrace volatile compounds with efficiency in treating different diseases. In Jordan, Syzygium aromaticum flower buds (clove) are extensively used as folk medicine without awareness of its bio-safe dosage. Herein, clove buds were hydrodistilled using the Clevenger apparatus, and the resulting essential oil (CEO) was analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The antibacterial activity was evaluated against tested bacterial strains by agar diffusion test and micro-broth dilution assay. The antioxidant capacity was assessed using DPPH radical scavenging assay, while the cytotoxic potency was unraveled by determination of its anti-proliferative activity against MDA-MB-231 breast adenocarcinoma and normal Vero cell lines. CEO yield was 5.7 ± 1.3% (w/w); encompassed 24 volatile ingredients with eugenol as the principal compound (73.41%). The CEO inhibited the growth of both Gram-positive and Gram-negative bacterial test strains, causing the formation of 13.7 ± 1.5-17.3 ± 0.6 mm and 11.7 ± 1.5-20.7 ± 1.2 mm inhibition zones, respectively with MIC 1.25-5 μL/mL. Moreover, it showed antioxidant activity with IC₅₀ 0.0016 ± 0.0001 μL/mL (1.6 ± 0.1 μg/mL, 2.98 ± 0.4 µg Trolox^®/µg CEO). Intriguingly, the CEO was cytotoxic against both cancerous and noncancerous cell lines at IC₅₀ of 0.25 ± 0.02 μL/mL and 0.18 ± 0.01 μL/mL, respectively. Herein results unveil the potential application of CEO as a pharmaceutical remedy with considering its bio-safe dosage.

Antimicrobial Fibrous Bandage-like Scaffolds Using Clove Bud Oil

Wounds are characterised by an anatomical disruption of the skin; this leaves the body exposed to opportunistic pathogens which contribute to infections. Current wound healing bandages do little to protect against this and when they do, they can often utilise harmful additions. Historically, plant-based constituents have been extensively used for wound treatment and are proven beneficial in such environments. In this work, the essential oil of clove bud (Syzygium aromaticum) was incorporated in a polycaprolactone (PCL) solution, and 44.4% (v/v) oil-containing fibres were produced through pressurised gyration. The antimicrobial activity of these bandage-like fibres was analysed using in vitro disk diffusion and the physical fibre properties were also assessed. The work showed that advantageous fibre morphologies were achieved with diameters of 10.90 ± 4.99 μm. The clove bud oil fibres demonstrated good antimicrobial properties. They exhibited inhibition zone diameters of 30, 18, 11, and 20 mm against microbial colonies of C. albicans, E. coli, S. aureus, and S. pyogenes, respectively. These microbial species are commonly problematic in environments where the skin barrier is compromised. The outcomes of this study are thus very promising and suggest that clove bud oil is highly suitable to be applied as a natural sustainable alternative to modern medicine.

The Effect of Eugenol Treatment on Diabetic Cardiomyopathy in Streptozotocin-Induced Diabetic Rats

Cardiovascular diseases account for most of the morbidity and mortality associated with diabetes. Diabetic cardiomyopathy (DCM) is associated with heart failure in diabetic patients without relation to other cardiovascular diseases such as hypertension or coronary artery disorders. Eugenol is a phenolic compound extracted from the clove tree and exhibits effective mitigation of hyperglycemic conditions in diabetic animals. Thus, in the current study, we aimed to explore the effect of eugenol treatment on rats with DCM. The experimental animals included 30 Sprague Dawley male rats which are divided into three experimental groups (10 rats each) as the following: the non-diabetic control group (ND), diabetic group (D), and a treated-diabetic group (20mg/kg/day of eugenol) (D+E). Diabetes was induced by streptozotocin (STZ) injection (60 mg/ kg). After 6 weeks, blood samples and left ventricles were collected for analysis. Serum glucose levels, heart weight/body weight ratio, and the myocardial mRNA expression of transforming growth factor β1 (TGF-β1), tumor necrosis factor-α (TNF-α), caspase 3 (casp3), vascular endothelial growth factor-A (VEGF-A), and collagen IV were evaluated. Furthermore, the myocardial superoxide dismutase (SOD) activity was measured. Diabetic rats showed a significant appearance of hyperglycemia and increased expression of myocardial TNF-α, TGF-β1, caspase 3, and VEGF-A compared to the control group (P < 0.05), and a tendency to increase collagen IV (P < 0.1). On the other hand, the eugenol treatment mitigates diabetic-associated hyperglycemia and the increased mRNA expression levels of myocardial TGF-β1, VEGF-A, caspase 3, and TNF-α (P < 0.05). In addition, the overexpression of collagen IV was inhibited, and the myocardial SOD activity was improved in the diabetic rats treated with eugenol. The study provided evidence that eugenol may have a potential therapeutic effect in the experimental models of DCM by reducing the expression of pro-inflammatory, pro-fibrotic, angiogenic, and pro-apoptotic factors (TNF-α, TGF-β, collagen IV, VEGF-A, and caspase 3 respectively). It is recommended for further studies investigate the exact molecular processes by which eugenol may ameliorate the DCM phenotype.

Analysis of the chemical compositions of six essential oils and evaluation of their antioxidant and antibacterial activities against some drug-resistant bacteria in aquaculture

Introduction: The extensive use of chemicals and antimicrobial agents in aquaculture has decreased the immune mechanisms of cultivated species and promoted the emergence of drug-resistant microorganisms leading to diseases among cultivated fish, affecting consumers’ health. Thus, the investigation of natural antibacterial and anti-stress agents is crucial. In the current study, we focused on the evaluation of the potential use of essential oils (EOs) as an antioxidant and antimicrobial agents in aquaculture. Methods: The EOs, obtained by hydrodistillation from clove (Syzygium aromaticum), cinnamon (Cinnamomum verum), rosemary (Rosmarinus officinalis), artemisia (Artemisia herba-alba), cedarwood (Cedrus atlantica) and oregano (Origanum compactum) were analyzed by gas chromatography/mass spectrometry (GC/MS). Their antibacterial activities were carried out against five bacteria, pathogenic to fish in aquaculture, using the well diffusion and microatmosphere methods. The pathogens used were Vibrio anguillarum, Photobacterium damselae subsp damselae, Aeromonas salmonicida, Edwardsiella tarda, and Lactococcus garvieae. Then, the minimum inhibitory and bactericidal concentrations of each EO were determined. Furthermore, the antioxidant activity was performed in vitro. Results: The investigated EOs were effective against the pathogenic strains. They showed variable constituents such as phenols, sesquiterpenes, and monoterpenes. Regarding the antioxidant activity, cinnamon, clove, and oregano EOs showed their abilities to donate hydrogen to 2,2-diphenyl-1-picrylhydrazy (DPPH) radical and scavenge free radicals produced by 2,2-azino-bis-3-ethylbenzothiazoline6-sulfonic acid (ABTS), respectively. Conclusion: These results gave insight into the potential use of phytobiotics in aquaculture as a safe strategy to substitute antibiotics to protect fish from oxidative stress and inhibit the emergence of drug-resistant bacteria for safer consumption of cultivated fish.

The Healing Capability of Clove Flower Extract (CFE) in Streptozotocin-Induced (STZ-Induced) Diabetic Rat Wounds Infected with Multidrug Resistant Bacteria

Treatment of diabetic foot ulcer (DFU) is of great challenge as it is shown to be infected by multidrug resistant bacteria (MDR bacteria). Sixty four bacterial isolates were isolated from DFU cases; antibiotic susceptibility tests were carried out for all of them. One bacterial isolate (number 11) was shown to resist the action of 8 out of 12 antibiotics used and was identified by both a Vitek-2 system and 16S rRNA fingerprints as belonging to Proteus mirabilis, and was designated Proteus mirabilis LC587231 (P. mirabilis). Clove flower extract (CFE) inhibited distinctively the P. mirabilis bacterium obtained. GC-MS spectroscopy showed that this CFE contained nine bioactive compounds. The effect of CFE on wound healing of Type 1 diabetic albino rats (Rattus norvegicus) was studied. The results indicated that topical application of CFE hydrogel improved wound size, wound index, mRNA expression of the wound healing markers (Coli1, MMP9, Fibronectin, PCNA, and TGFβ), growth factor signaling pathways (PPAR-α, PGC1-α, GLP-1, GLPr-1, EGF-β, EGF-βr, VEGF-β, and FGF-β), inflammatory cytokine expression (IL8, TNFα, NFKβ, IL1β, and MCP1), as well as anti-inflammatory cytokines (IL4 & IL10), pro-apoptotic markers (FAS, FAS-L, BAX, BAX/BCL-2, Caspase-3, P53, P38), as well as an antiapoptotic one (BCL2). Furthermore, it improved the wound oxidative state and reduced the wound microbial load, as the cefepime therapy improved the wound healing parameters. Based on the previous notions, it could be concluded that CFE represents a valid antibiotics alternative for DFU therapy since it improves diabetic wound healing and exerts antibacterial activity either in vitro or in vivo.

Culinary Spices in Food and Medicine: An Overview of Syzygium aromaticum (L.) Merr. and L. M. Perry [Myrtaceae]

Spices-dried aromatic parts of plants (leaves, seeds, bark, roots, rhizomes, buds, etc) used to enhance flavour, taste and colour (sensory quality) of foods, are increasingly finding other useful roles in healthcare beyond their primary use as culinary organoleptic enhancers. Several spices are currently being investigated for their potential health benefits, because of the failing efficacy, toxicity and high cost associated with conventional drugs. One such spice: Syzygium aromaticum (L.) Merr. and L.M.Perry [Myrtaceae] (Clove), has a multi-dimensional role in diet, medicine, functional foods and nutraceuticals, agriculture, among other industries. Peer-reviewed articles, mostly from PubMed and Google Scholar, were consulted for the purpose of this review. The nutritional and phytochemical contents, selected biological activities as well as some functional foods and beverages of clove and their uses for human health are presented. Although these observations are largely empirical, the efficacious attributes have led to their pharmacological applications in the indigenous system of medicine all over the world and bridge between food, diet and medicine. Considering the GRAS status of clove, more studies on bioavailability, accumulation, toxicity, dosage and efficacy of clove as a spice drug or functional foods in biological systems especially in humans are required. Meanwhile, clove and its products can be used as co-adjuvants in the prevention, treatment and management of chronic diseases. Further, many applications of clove in food, health, cosmetics, pharmaceutics, nanoparticles and agricultural industries are still open for investigations.

Phytochemical Characterization and Evaluation of the Antioxidant and Anti-Enzymatic Activity of Five Common Spices: Focus on Their Essential Oils and Spent Material Extractives

The essential oil industry of aromatic herbs and spices is currently producing a significant amount of by-products, such as the spent plant materials remaining after steam or hydrodistillation, that are simply discarded. The aim of this study was to comparatively investigate the phytochemical composition, antioxidant and multi-enzymatic inhibitory potential of the essential oils and spent plant material extractives obtained from cinnamon, cumin, clove, laurel, and black pepper. The essential oils were characterized by the presence of several phytochemical markers (cinnamaldehyde, cuminaldehyde, eugenol, eucalyptol, α-terpinene, limonene, β-caryophyllene or β-pinene). On the other hand, the LC-HRMS/MS profiling of the spent material extracts allowed the annotation of species specific and non-specific metabolites, such as organic acids, phenolic acids, flavonoids, proanthocyanidins, hydrolysable tannins, fatty acids, or piperamides. All samples exhibited very strong antioxidant effects, with the clove essential oil displaying the strongest radical scavenging (525.78 and 936.44 mg TE/g in DPPH and ABTS assays), reducing (2848.28 and 1927.98 mg TE/g in CUPRAC and FRAP), and total antioxidant capacity (68.19 mmol TE/g). With respect to the anti-acetylcholinesterase (0.73-2.95 mg GALAE/g), anti-butyrylcholinesterase (0-3.41 mg GALAE/g), anti-tyrosinase (0-76.86 mg KAE/g), anti-amylase and anti-glucosidase (both 0-1.00 mmol ACAE/g) assays, the spice samples showed a modest activity. Overall, our study reports that, not only the volatile fractions of common spices, but also their spent plant materials remaining after hydrodistillation can be regarded as rich sources of bioactive molecules with antioxidant and multi-enzymatic inhibitory effects.

Antiaging Properties of the Ethanol Fractions of Clove (Syzygium aromaticum L.) Bud and Leaf at the Cellular Levels: Study in Yeast Schizosaccharomyces pombe

The exposure of reactive oxygen species is one of the aging triggers at cellular level. The antioxidants have been used as strategic efforts in overcoming the accumulation of ROS. Previous research using crude extracts of clove bud and leaves showed its potential as an antioxidant agent. However, no data were available regarding the antioxidant and antiaging activities of subsequent fractions of clove extracts. Therefore, this study aimed to analyze the antioxidant and antiaging activities of the n-hexane and ethanol fractions from clove bud and leaves. Antioxidant and antiaging activities were tested at the cellular level using the yeast model Schizosaccharomyces pombe. The highest flavonoid content was shown by clove leaf n-hexane fraction (25.6 mgQE·g−1). However, ethanol fraction of clove bud (FEB) showed the highest antioxidant activity based on TBA and antiglycation assays. FEB (8 μg·mL−1) and leaf ethanol fraction (FEL) (10 μg·mL−1) were able to induce yeast tolerance against oxidative stress. In addition, FEB could induce mitochondrial activity and delay the G1 phase of the cell cycle. FEB was found to be rich in gallic acid and (15Z)-9,12,13-trihydroxy-15-octadecenoic. Based on the data, FEB shows the potential antiaging activity, which is promising for further development as biopharmaceutical product formulations.

Exploring combined herbal extract-loaded phytoniosomes for antimalarial and antibacterial activity against methicillin-resistant Staphylococcus aureus

Antibiotic resistance in the context of treating malarial infections is a major challenge in India. Home remedies such as thulasi leaves (Ocimum tenuiflorum), black pepper seeds (Piper nigrum), clove buds (Syzygium aromaticum), cinnamon bark (Cinnamomum verum), and nilavembu whole plant powder (Andrographis paniculata) were taken to explore antimalarial and methicillin-resistant Staphylococcus aureus (MRSA) activity. Among the five extracts, the best two extracts, C. verum and P. nigrum extract, showed the presence of Quercetin. Phytoniosomes were prepared by simple probe sonication with the two extracts and the resultant vesicles were in the size range of (319.7 nm). They showed significant (P < 0.001) antimalarial potency IC₅₀ at 5.25 µg/ml against P. falciparum 3D7. In addition, their cytotoxicity (TC₅₀) against Vero cell line was found to be > 100 µg/ml. The therapeutic index was found to be > 32 µg/ml. Phytoniosomes were converted to a capsule dosage form by lyophilization and this capsule was stable up to 90 days.

Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea, Rosemary, Clove, and Oregano

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.

Molecular Basis of the Therapeutical Potential of Clove (Syzygium aromaticum L.) and Clues to Its Anti-COVID-19 Utility

The current COronaVIrus Disease 19 (COVID-19) pandemic caused by SARS-CoV-2 infection is enormously affecting the worldwide health and economy. In the wait for an effective global immunization, the development of a specific therapeutic protocol to treat COVID-19 patients is clearly necessary as a short-term solution of the problem. Drug repurposing and herbal medicine represent two of the most explored strategies for an anti-COVID-19 drug discovery. Clove (Syzygium aromaticum L.) is a well-known culinary spice that has been used for centuries in folk medicine in many disorders. Interestingly, traditional medicines have used clove since ancient times to treat respiratory ailments, whilst clove ingredients show antiviral and anti-inflammatory properties. Other interesting features are the clove antithrombotic, immunostimulatory, and antibacterial effects. Thus, in this review, we discuss the potential role of clove in the frame of anti-COVID-19 therapy, focusing on the antiviral, anti-inflammatory, and antithrombotic effects of clove and its molecular constituents described in the scientific literature.

Plant Natural Sources of the Endocannabinoid (E)-β-Caryophyllene: A Systematic Quantitative Analysis of Published Literature

(E)-β-caryophyllene (BCP) is a natural sesquiterpene hydrocarbon present in hundreds of plant species. BCP possesses several important pharmacological activities, ranging from pain treatment to neurological and metabolic disorders. These are mainly due to its ability to interact with the cannabinoid receptor 2 (CB2) and the complete lack of interaction with the brain CB1. A systematic analysis of plant species with essential oils containing a BCP percentage > 10% provided almost 300 entries with species belonging to 51 families. The essential oils were found to be extracted from 13 plant parts and samples originated from 56 countries worldwide. Statistical analyses included the evaluation of variability in BCP% and yield% as well as the statistical linkage between families, plant parts and countries of origin by cluster analysis. Identified species were also grouped according to their presence in the Belfrit list. The survey evidences the importance of essential oil yield evaluation in support of the chemical analysis. The results provide a comprehensive picture of the species with the highest BCP and yield percentages.

In Vitro Wound Healing Activities of Three Most Commonly Used Thai Medicinal Plants and Their Three Markers

Skin ensures that a constant internal environment can be maintained in an ever-changing external environment. When a wound occurs on the skin, the inflammatory and proliferative phases are initiated in response to injury. Thai traditional medicine (TTM), using medicinal plants and ancient knowledge, has been used to treat wounds. Eight Thai medicinal plants, most commonly used to treat wounds, were evaluated for their in vitro biological activities such as antioxidation by NBT assay, anti-inflammation by production inhibition of NO, promoting fibroblast cell proliferation, and wound closure activities. Plant materials were extracted with 95% ethanol or distilled water and then concentrated and dried. Statistical analysis of data was done using one-way ANOVA at p value of 0.05. The ethanolic extracts of Garcinia mangostana L., Glycyrrhiza glabra L., and Nigella sativa L. could inhibit the production of superoxide anion with the IC₅₀ values of 13.97 ± 0.38, 28.62 ± 1.91, and 71.54 ± 3.22 μg/ml and nitric oxide with the IC₅₀ values of 23.97 ± 0.91, 46.35 ± 0.43, and 78.48 ± 4.46 μg/ml, respectively. These extracts could promote cell proliferation and accelerate wound recovery at the rate of 2.02 ± 0.03, 2.12 ± 0.03, and 2.65 ± 0.05% per hour, respectively. Three established markers from these three plants were selected according to the selection criteria. Alpha-mangostin, glycyrrhizin, and thymoquinone were found to be the active markers for wound closure activities. The ethanolic extracts of G. mangostana, G. glabra, and N. sativa could scavenge superoxide anion and inhibit the production of nitric oxide; therefore these extracts could assist in surpassing the inflammatory phase and protected the cells surrounding the wound area. Most importantly, these extracts also increased the proliferation and accelerated wound closure, indicating that these plant extracts could be promoting wound healing processes and support the use of TTM.