Variability of the Chemical Composition and Bioactivity between the Essential Oils Isolated from Male and Female Specimens of Hedyosmum racemosum (Ruiz & Pav.) G. Don.

Hedyosmum racemosum (Ruiz & Pav.) G. is a native species of Ecuador used in traditional medicine for treatment of rheumatism, bronchitis, cold, cough, asthma, bone pain, and stomach pain. In this study, fresh H. racemosum leaves of male and female specimens were collected and subjected to hydrodistillation for the extraction of the essential oil. The chemical composition of male and female essential oil was determined by gas chromatography-gas chromatography equipped with a flame ionization detector and coupled to a mass spectrometer using a non-polar and a polar chromatographic column. The antibacterial activity was assayed against five Gram-positive and two Gram-negative bacteria, and two dermatophytes fungi. The scavenging radical properties of the essential oil were evaluated by DPPH and ABTS assays. The chemical analysis allowed us to identify forty-three compounds that represent more than 98% of the total composition. In the non-polar and polar column, α-phellandrene was the principal constituent in male (28.24 and 25.90%) and female (26.47 and 23.90%) essential oil. Other main compounds were methyl chavicol, germacrene D, methyl eugenol, and α-pinene. Female essential oil presented a strong activity against Klebsiella pneumoniae (ATCC 9997) with an minimum inhibitory concentration (MIC) of 500 µg/mL and a scavenging capacity SC50 of 800 µg/mL.

Eugenol as a Potential Drug Candidate: A Review.

Eugenol is a bioactive compound widely available in many herbs like clove, cinnamon, tulsi, pepper etc. The compound is known for its antioxidant, antimicrobial, anesthetic, anti-inflammatory, neuroprotective, anti-diabetic, and anti-cancer activities. In pharmaceutical analysis, eugenol is used as a marker for single drugs and drug products. Dental care, household, and personal hygiene products are other areas where it has established its potential. In the food industry, eugenol is used as a flavouring agent in non-alcoholic beverages, baked foods, and chewing gums. Considering the huge potential of eugenol, this review is an attempt to collate the regulatory information, physico-chemical properties, toxicity profile, marketed conventional and novel formulations, analytical methods, extraction procedures, recent patents and clinical trials of the moiety. Based on literature survey a schematic diagram of mechanism of action has also been made.

Dehydrodieugenol improved lung inflammation in an asthma model by inhibiting the STAT3/SOCS3 and MAPK pathways.

BACKGROUND: Eugenol, a common phenylpropanoid derivative found in different plant species, has well-described anti-inflammatory effects associated with the development of occupational hypersensitive asthma. Dehydrodieugenol, a dimeric eugenol derivative, exhibits anti-inflammatory and antioxidant activities and can be found in the Brazilian plant species Nectandra leucantha (Lauraceae). The biological effects of dehydrodieugenol on lung inflammation remain unclear. PURPOSE: This study aimed to investigate the effects of eugenol and dehydrodieugenol isolated from N. leucantha in an experimental model of asthma. METHODS: In the present work, the toxic effects of eugenol and dehydrodieugenol on RAW 264.7 cells and their oxidant and inflammatory effects before lipopolysaccharide (LPS) exposure were tested. Then, male BALB/c mice were sensitized with ovalbumin through a 29-day protocol and treated with vehicle, eugenol, dehydrodieugenol or dexamethasone for eight days beginning on the 22nd day until the end of the protocol. Lung function; the inflammatory profile; and the protein expression of ERK1/2, JNK, p38, VAChT, STAT3, and SOCS3 in the lung were evaluated by immunoblotting. RESULTS: Eugenol and dehydrodieugenol were nontoxic to cells. Both compounds inhibited NO release and the gene expression of IL-1ß and IL-6 in LPS-stimulated RAW 264.7 cells. In OVA-sensitized animals, dehydrodieugenol reduced lung inflammatory cell numbers and the lung concentrations of IL-4, IL-13, IL-17, and IL-10. These anti-inflammatory effects were associated with inhibition of the JNK, p38 and ERK1/2, VAChT and STAT3/SOCS3 pathways. Moreover, treatment with dehydrodieugenol effectively attenuated airway hyperresponsiveness. CONCLUSION: The obtained data demonstrate, for the first time, that dehydrodieugenol was more effective than eugenol in counteracting allergic airway inflammation in mice, especially its inhibition of the JNK, p38 and ERK1/2, components of MAPK pathway. Therefore, dehydrodieugenol can be considered a prototype for the development of new and effective agents for the treatment of asthmatic patients.

Comparative Analysis of In-Vitro Biological Activities of Methyl Eugenol Rich Cymbopogon khasianus Hack., Leaf Essential Oil with Pure Methyl Eugenol Compound.

BACKGROUND: The essential oil of methyl eugenol rich Cymbopogon khasianus Hack. was evaluated and its bioactivities were compared with pure methyl eugenol. So far, methyl eugenol rich essential oil of lemongrass was not studied for any biological activities; hence, the present study was conducted. OBJECTIVE: This study examined the chemical composition of essential oil of methyl eugenol rich Cymbopogon khasianus Hack., and evaluated its antioxidant, anti-inflammatory, antimicrobial, and herbicidal properties and genotoxicity, which were compared with pure compound, methyl eugenol. MATERIAL AND METHODS: Methyl eugenol rich variety of Cymbopogon khasianus Hack., with registration no. INGR18037 (c.v. Jor Lab L-9) was collected from experimental farm CSIR-NEIST, Jorhat, Assam (26.7378°N, 94.1570°E). The essential oil wasobtained by hydro-distillation using a Clevenger apparatus. The chemical composition of the essential oil was evaluated using GC/MS analysis and its antioxidant (DPPH assay, reducing power assay), anti-inflammatory (Egg albumin denaturation assay), and antimicrobial (Disc diffusion assay, MIC) properties, seed germination effect and genotoxicity (Allium cepa assay) were studied and compared with pure Methyl Eugenol compound (ME). RESULTS: Major components detected in the Essential Oil (EO) through Gas chromatography/mass spectroscopy analysis were methyl eugenol (73.17%) and ß-myrcene (8.58%). A total of 35components were detected with a total identified area percentage of 98.34%. DPPH assay revealed considerable antioxidant activity of methyl eugenol rich lemongrass essential oil (IC50= 2.263 µg/mL), which is lower than standard ascorbic acid (IC50 2.58 µg/mL), and higher than standard Methyl Eugenol (ME) (IC50 2.253 µg/mL). Methyl eugenol rich lemongrass EO showed IC50 38.00 µg/mL, ME 36.44 µg/mL, and sodium diclofenac 22.76 µg/mL, in in-vitro anti-inflammatory test. Moderate antimicrobial activity towards the 8 tested microbes was shown by methyl eugenol rich lemongrass essential oil whose effectiveness against the microbes was less as compared to pure ME standard. Seed germination assay further revealed the herbicidal properties of methyl eugenol rich essential oil. Moreover, Allium cepa assay revealed moderate genotoxicity of the essential oil. CONCLUSION: This paper compared the antioxidant, anti-inflammatory, antimicrobial, genotoxicity and herbicidal activities of methyl eugenol rich lemongrass with pure methyl eugenol. This methyl eugenol rich lemongrass variety can be used as an alternative of methyl eugenol pure compound. Hence, the essential oil of this variety has the potential of developing cost-effective, easily available antioxidative/ antimicrobial drugs but its use should be under the safety range of methyl eugenol and needs further clinical trials.

Electrospray mass-spectrometry guided target isolation of neolignans from Nectandra leucantha (Lauraceae) by high performance- and spiral-coil countercurrent chromatography.

Nectandra leucantha (Lauraceae) is a tree indigenous to the tropical Atlantic forests of Brazil, one of the most biodiverse flora hotspots worldwide. This plant species contains high concentrations of neolignan and dehydrodieugenol derivatives that express significant in-vitro activities against various parasite strains. These activities are however responsible for severe tropical human infections, such as Leishmaniasis (Leishmania spp.) and Chagas disease (Trypanosoma cruzi), which have been classified by the World Health Organization (WHO) as Neglected Tropical Diseases (NTDs). In order to optimize the isolation process for these target metabolites, n-hexane extract of the leaves was separated by means of semi-preparative high performance countercurrent chromatography (HPCCC) and scale-up spiral-coil countercurrent chromatography (sp-CCC) systems. Several biphasic solvent mixtures were evaluated for their partitioning effects on neolignans, resulting in the selection of an optimized system n-hexane - ethylacetate - methanol - water (7:3:7:3, v/v/v/v). The chromatographic experiments on the HPCCC and sp-CCC were run in the head-to-tail mode with 500 mg and 16 g injections, respectively. For specific and multiple metabolite detection, the recovered CCC-fractions were off-line injected, in the sequence of recovery, to an electrospray mass-spectrometry (ESI-MS/MS) device. A projection of the single ion traces of the target compounds, in the positive ionization mode at a scan range of m/z 100-1500, located chromatographic areas where the co-elution effects occurred and pure target metabolites were present. Five major target neolignans were specifically detected, which enabled the accurate pooling of CCC-fractions for an optimum recovery of the metabolites. The direct comparison of the performance characteristics of the two CCC-devices, with very different mechanical designs was achieved by the conversion of the time axis into a partition ratio (KD) separation scale. As a result, the compound specific KD-elution values of the target neolignan were determined in high precision, while the comparison of the calculated separation factor (α) and resolution factor (RS) values revealed a superior separation performance for the HPCCC system. Also, the reproducibility of detected metabolites in the two CCC experiments was confirmed by small variations (ΔKD ±0.1). Neolignan target compounds with anti-parasite activities were successfully isolated in the 100 mg to 4 g range in a single lab-scale countercurrent chromatographic process step.

Characterization of the Key Aroma Compounds in Marselan Wine by Gas Chromatography-Olfactometry, Quantitative Measurements, Aroma Recombination, and Omission Tests.

Key odorants of red wine made from the hybrid grapes of Marselan (Vitis vinifera L.) were isolated by solid-phase extraction (SPE) and explored by gas chromatography-olfactometry (GC-O) analysis. Application of aroma extract dilution analysis (AEDA) revealed 43 odor-active compounds, and 31 odorants among them were detected with flavor dilution (FD) factors ranging from 9 to 2187. Comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-TOF-MS) were exploited to quantitate the aroma-active compounds with FD ≥9. The identification indicated ß-damascenone as having the highest FD factors, followed by eugenol, 2,3-butanedione, citronellol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, phenethyl acetate, guaiacol, and 2-methoxy-4-vinylphenol. A total of 21 compounds were found to have odor activity values (OAVs) >1.0. Aroma reconstitution validation experiments showed a good similarity of blackberry, green pepper, honey, raspberry, caramel, smoky, and cinnamon aroma attributes between the original Marselan wine and the reconstructed wine. In addition, omission tests were carried out to further determine the contribution of odorants to the overall aroma.

Hydroxychavicol from Piper betle induces apoptosis, cell cycle arrest, and inhibits epithelial-mesenchymal transition in pancreatic cancer cells.

Pancreatic cancer is a major cause of cancer-related mortality around the world. Currently, options for diagnosis and treatment are extremely limited, which culminates in a very high mortality rate. Intensive research spanning more than four decades has met several roadblocks in terms of improvement in overall survival. In this study, we have evaluated the effect of Hydroxychavicol (HC), a naturally occurring and abundantly isolatable allylarene from Piper betle leaves on pancreatic cancer cells. Our investigation reveals that HC inhibits proliferation and epithelial-mesenchymal transition (EMT) in pancreatic cancer cells. HC induces DNA damage, as evidenced by γ-H2AX, 53BP1 induction and comet assay, which further results in mitotic catastrophe and apoptosis. The apoptosis induced by HC is JNK pathway-dependent and caspase-mediated. HC also inhibits migration and invasion of pancreatic cancer cells via a generalized repression of genes involved in EMT. A quantitative real time PCR-based array revealed at least 14 different genes to be differentially expressed upon HC treatment in pancreatic cancer cells. These results show significant potential of HC as an anticancer agent against pancreatic cancer.

Identification of key odorant compounds in starch-based polymers intended for food contact materials.

Biopolymers used for food contact materials must be evaluated in order to ensure food safety and quality. In this work, the aroma profile of starch-based packaging materials, presented as pellets and films has been characterized. Headspace solid phase microextraction (HS-SPME) technique and gas chromatography coupled to both mass spectrometry and a sniffing port (GC-MS-O) were used for identification. In total, 35 odorant compounds were detected. The results showed that aldehydes were the odorants with the highest aromatic impact in starch-based films. Eight odorant compounds, such as trimethylamine, 1-octen-3-one, sotolon, (Z) and (E)-2-nonenal, p-vinylguaiacol, eugenol and 1-undecanol, defined as aroma-impact compounds, obtained modified frequency values (MF%) above 60% in at least 3 out of 4 films. A sensory panel evaluated the toasted, sweet/fruity, green, flower, distasteful, fat and spices notes in the films and it was observed that the quality of all samples decreased when the toasted and spices notes increased.

In vitro susceptibility of Microsporum spp. and mammalian cells to Eugenia caryophyllus essential oil, eugenol and semisynthetic derivatives.

BACKGROUND: Microsporum spp. are keratinophilic dermatophytes that mainly invade the stratum corneum of the skin and hair causing clinical symptoms associated with tinea. Its treatment has several limitations, and the search for new active molecules is necessary. OBJECTIVE: To evaluate the antifungal and cytotoxic potential of Eugenia caryophyllus essential oil (EO), eugenol, isoeugenol and methylisoeugenol against Microsporum canis, M. gypseum and Vero cells. METHODS: The EO was extracted by conventional heating-assisted hydrodistillation, the eugenol obtained commercially and the derivatives through Williamson synthesis. Minimal inhibitory concentration (MICs), minimum fungicidal concentration, inhibition of radial mycelial growth and germination inhibition were used to evaluate the antifungal activity. In addition, a colorimetric test was conducted to evaluate cytotoxic activity. RESULTS: MIC and MFC values for all compounds were 62.5-500 µg/mL for both of the species of Microsporum evaluated. Also, concentrations of 300 µg/mL of the compounds inhibited 100% of M. canis mycelium. The inhibition of germination was observed after 6 hours of treatment (11.86 ± 3.46-85.31 ± 0%). No cytotoxicity was observed in Vero cells (CC50  > 105 µg/mL), whereas terbinafine showed CC50 31.00 ± 0.61 µg/mL. CONCLUSIONS: Our study indicates an interesting bioactivity of isoeugenol and methylisoeugenol against M. canis, M. gypseum and mammalian cells.

Eugenol and carvacrol migration from PHBV films and antibacterial action in different food matrices.

The antibacterial effect of PHBV films with oregano or clove essential oil, or their main compounds, carvacrol (CA) and eugenol (EU), respectively, was analysed in food matrices (cheese, chicken breast and pumpkin and melon) and in vitro test for Escherichia coli and Listeria innocua. The migration of CA and EU in the different food matrices was determined to analyse the food matrix effect on the film's antimicrobial effectiveness. The antimicrobial activity in foods was less remarkable than in in vitro test. Despite the antilisterial effect in the in vitro test, this was not noticed in any food matrix. The most significant antibacterial effects against E. coli were observed in cheese and pumpkin, whereas the highest migration of both CA and UE took place in melon. This lack of correlation reflected that many compositional factors affect the active compound's availability to exert its antibacterial action in a specific food.

Isolation of Chavibetol and Methyleugenol from Essential Oil of Pimenta pseudocaryophyllus by High Performance Liquid Chromatography.

A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of P. pseudocaryophyllus leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID. Chavibetol was isolated with high purity (98.7%) and mass recovery (94.6%). The mass recovery (86.4%) and purity (85.3%) of methyleugenol were lower than those of chavibetol. Both compounds were identified on the basis of spectral analysis. The results suggest that the method can provide chavibetol with high purity, mass recovery, and productivity from crude essential, which will be used in bioassays against stored insect pests.

Relaxant effects of Peperomia hispidula (Sw.) A. Dietr. on isolated rat tracheal rings / Efecto relajante de Peperomia hispidula (Sw.) A. Dietr. sobre anillos aislados de tráquea de rata

Peperomia hispidula (Sw.) A. Dietr. is used in Mexican traditional medicine for treating respiratory illnesses such as asthma. The latter disorder results from an excessive and inappropriate constriction of airway smooth muscle. The aim of the present study was to evaluate the relaxant activity of P. hispidula on isolated rat tracheal rings contracted with carbachol. The methyleugenol was identified as the main active constituent in the dichloromethane extract. To explore the possible mechanism of action, concentration-response curves were constructed in the presence and absence of propranolol (3 µM), indomethacin (10 µM), glibenclamide (1 µM), and L-NAME (300 µM), finding that neither reduced methyleugenol-induced smooth muscle relaxation. In conclusion, P. hispidula herein displayed relaxant activity on rat tracheal rings. The effect of methyleugenol, was probably not related to the activation of ß2-adrenoceptors, prostaglandins, K+ATP channels or nitric oxide.

Peperomia hispidula (Sw.) A. Dietr. es utilizada en la medicina tradicional mexicana para tratar enfermedades respiratorias como el asma. Este último trastorno es el resultado de una contracción excesiva e inapropiada del músculo liso de las vías respiratorias. El objetivo del presente estudio fue evaluar la actividad relajante de P. hispidula sobre anillos aislados de tráquea de rata contraídos con carbacol. El metileugenol fue identificado como el principal constituyente activo en el extracto de diclorometano. Para explorar el posible mecanismo de acción, se construyeron curvas concentración-respuesta en presencia y ausencia de propranolol (3 µM), indometacina (10 µM), glibenclamida (1 µM), y L-NAME (300 µM), encontrando que ninguno redujo la relajación del músculo liso inducida por metileugenol. En conclusión, P. hispidula muestra actividad relajante en anillos de tráquea de rata. El efecto de metileugenol, al parecer no está implicado con la activación de los receptores ß2-adrenérgicos, prostaglandinas, canales de K+ATP u óxido nítrico.

Structure-Activity Relationships and Docking Studies of Hydroxychavicol and Its Analogs as Xanthine Oxidase Inhibitors.

Hydroxychavicol (HC), which is obtained from the leaves of Piper betle LINN. (Piperaceae), inhibits xanthine oxidase (XO) with an IC50 value of 16.7 µM, making it more potent than the clinically used allopurinol (IC50=30.7 µM). Herein, a structure-activity relationship analysis of the polar part analogs of HC was conducted and an inhibitor was discovered with a potency 13 times that of HC. Kinetic studies have revealed that HC and its active analog inhibit XO in an uncompetitive manner. The binding structure prediction of these inhibitor molecules to the XO complex with xanthine suggested that both compounds (HC and its analog) could simultaneously form hydrogen bonds with xanthine and XO.

Phytochemical Analysis, Identification and Quantification of Antibacterial Active Compounds in Betel Leaves, Piper betle Methanolic Extract.

BACKGROUND AND OBJECTIVE: The problems of bacterial diseases in aquaculture are primarily controlled by antibiotics. Medicinal plants and herbs which are seemed to be candidates of replacements for conventional antibiotics have therefore gained increasing interest. Current study was performed to investigate the presence of phytochemical constituents, antibacterial activities and composition of antibacterial active compounds in methanolic extract of local herb, Piper betle . METHODOLOGY: Qualitative phytochemical analysis was firstly carried out to determine the possible active compounds in P. betle leaves methanolic extract. The antibacterial activities of major compounds from this extract against nine fish pathogenic bacteria were then assessed using TLC-bioautography agar overlay assay and their quantity were determined simultaneously by HPLC method. RESULTS: The use of methanol has proved to be successful in extracting numerous bioactive compounds including antibacterial compounds. The TLC-bioautography assay revealed the inhibitory action of two compounds which were identified as hydroxychavicol and eugenol. The $-caryophyllene however was totally inactive against all the tested bacterial species. In this study, the concentration of hydroxychavicol in extract was found to be 374.72±2.79 mg g-1, while eugenol was 49.67±0.16 mg g-1. CONCLUSION: Based on these findings, it could be concluded that hydroxychavicol and eugenol were the responsible compounds for the promising antibacterial activity of P. betle leaves methanolic extract. This inhibitory action has significantly correlated with the amount of the compounds in extract. Due to its potential, the extract of P. betle leaves or it compounds can be alternative source of potent natural antibacterial agents for aquaculture disease management.

The effect of drought stress on the expression of key genes involved in the biosynthesis of phenylpropanoids and essential oil components in basil (Ocimum basilicum L.).

Basil (Ocimum basilicum L.), a medicinal plant of the Lamiaceae family, is used in traditional medicine; its essential oil is a rich source of phenylpropanoids. Methylchavicol and methyleugenol are the most important constituents of basil essential oil. Drought stress is proposed to enhance the essential oil composition and expression levels of the genes involved in its biosynthesis. In the current investigation, an experiment based on a completely randomized design (CRD) with three replications was conducted in the greenhouse to study the effect of drought stress on the expression level of four genes involved in the phenylpropanoid biosynthesis pathway in O. basilicum c.v. Keshkeni luvelou. The genes studied were chavicol O-methyl transferase (CVOMT), eugenol O-methyl transferase (EOMT), cinnamate 4-hydroxylase (C4H), 4-coumarate coA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). The effect of drought stress on the essential oil compounds and their relationship with the expression levels of the studied genes were also investigated. Plants were subjected to levels of 100%, 75%, and 50% of field capacity (FC) at the 6-8 leaf stage. Essential oil compounds were identified by gas chromatography/mass spectrometry (GC-MS) at flowering stage and the levels of gene expression were determind by real time PCR in plant leaves at the same stage. Results showed that drought stress increased the amount of methylchavicol, methyleugenol, ß-Myrcene and α-bergamotene. The maximum amount of these compounds was observed at 50% FC. Real-time PCR analysis revealed that severe drought stress (50% FC) increased the expression level of CVOMT and EOMT by about 6.46 and 46.33 times, respectively, whereas those of CAD relatively remained unchanged. The expression level of 4CL and C4H reduced under drought stress conditions. Our results also demonstrated that changes in the expression levels of CVOMT and EOMT are significantly correlated with methylchavicol (r = 0.94, P ≤ 0.05) and methyleugenol (r = 0.98, P ≤ 0.05) content. Thus, drought stress probably increases the methylchavicol and methyleugenol content, in part, through increasing the expression levels of CVOMT and EOMT.

Anti-inflammatory activity of clove (Eugenia caryophyllata) essential oil in human dermal fibroblasts.

CONTEXT: Clove (Eugenia caryophyllata Thunb. [Myrtaceae]) essential oil (CEO) has been shown to possess antimicrobial, antifungal, antiviral, antioxidant, anti-inflammatory and anticancer properties. However, few studies have focused on its topical use. OBJECTIVE: We investigated the biological activity of a commercially available CEO in a human skin disease model. MATERIALS AND METHODS: We evaluated the effect of CEO on 17 protein biomarkers that play critical roles in inflammation and tissue remodelling in a validated human dermal fibroblast system, which was designed to model chronic inflammation and fibrosis. Four concentrations of CEO (0.011, 0.0037, 0.0012, and 0.00041%, v/v) were studied. The effect of 0.011% CEO on genome-wide gene expression was also evaluated. RESULTS AND DISCUSSION: CEO at a concentration of 0.011% showed robust antiproliferative effects on human dermal fibroblasts. It significantly inhibited the increased production of several proinflammatory biomarkers such as vascular cell adhesion molecule-1 (VCAM-1), interferon γ-induced protein 10 (IP-10), interferon-inducible T-cell α chemoattractant (I-TAC), and monokine induced by γ interferon (MIG). CEO also significantly inhibited tissue remodelling protein molecules, namely, collagen-I, collagen-III, macrophage colony-stimulating factor (M-CSF), and tissue inhibitor of metalloproteinase 2 (TIMP-2). Furthermore, it significantly modulated global gene expression and altered signalling pathways critical for inflammation, tissue remodelling, and cancer signalling processes. CEO significantly inhibited VCAM-1 and collagen III at both protein and gene expression levels. CONCLUSIONS: This study provides important evidence of CEO-induced anti-inflammatory and tissue remodelling activity in human dermal fibroblasts. This study also supports the anticancer properties of CEO and its major active component eugenol.

In Vitro Incorporation of Radioiodinated Eugenol on Adenocarcinoma Cell Lines (Caco2, MCF7, and PC3).

Recently, the synthesis of radiolabeled plant origin compounds has been increased due to their high uptake on some cancer cell lines. Eugenol (EUG), a phenolic natural compound in the essential oils of different spices such as Syzygium aromaticum (clove), Pimenta racemosa (bay leaves), and Cinnamomum verum (cinnamon leaf), has been exploited for various medicinal applications. EUG has antiviral, antioxidant, and anti-inflammatory functions and several anticancer properties. The objective of this article is to synthesize radioiodinated (131I) EUG and investigate its effect on Caco2, MCF7, and PC3 adenocarcinoma cell lines. It is observed that radioiodinated EUG would have potential on therapy and imaging due to its notable uptakes in studied cells.

Antibacterial activity of Pyrrosia petiolosa ethyl acetate extract against Staphylococcus aureus by decreasing hla and sea virulence genes.

The aim of this study was to explore the antibacterial activity of Pyrrosia petiolosa ethyl acetate extract (PPEAE) against Staphylococcus aureus in vitro and analyse its chemical components by gas chromatograph-mass spectrometry. The results of anti-microbial assay revealed that PPEAE had strong inhibitory activity against S .aureus, with MIC and MBC of 7.8 and 15.6 mg/mL, respectively. The transcriptional levels of hla and sea were reduced to 14.33 and 46.39% at the MIC compared to the control. Analysing test result exhibited that eugenol made a great contribution to antibacterial activity. This experiment indicated that PPEAE had prominent antibacterial activity against S. aureus.

Eugenol and Its Role in Chronic Diseases.

The active components in cloves are eugenol and isoeugenol. Eugenol has recently become a focus of interest because of its potential role in alleviating and preventing chronic diseases such as cancer, inflammatory reactions, and other conditions. The radical-scavenging and anti-inflammatory activities of eugenol have been shown to modulate chronic diseases in vitro and in vivo, but in humans, the therapeutic use of eugenol still remains to be explored. Based on a review of the recent literature, the antioxidant, anti-proliferative, and anti-inflammatory activities of eugenol and its related compounds are discussed in relation to experimentally determined antioxidant activity (stoichiometric factor n and inhibition rate constant) and theoretical parameters [phenolic O-H bond dissociation enthalpy (BDE), ionization potential (IP according to Koopman's theorem), and electrophilicity (ω)], calculated using a density functional theory method. Dimers of eugenol and its related compounds showed large antioxidant activities and high ω values and also exerted efficient anti-inflammatory activities. Eugenol appears to possess multiple antioxidant activities (dimerization, recycling, and chelating effect) in one molecule, thus having the potential to alleviate and prevent chronic diseases.

Comparative functional characterization of eugenol synthase from four different Ocimum species: Implications on eugenol accumulation.

Isoprenoids and phenylpropanoids are the major secondary metabolite constituents in Ocimum genus. Though enzymes from phenylpropanoid pathway have been characterized from few plants, limited information exists on how they modulate levels of secondary metabolites. Here, we performed phenylpropanoid profiling in different tissues from five Ocimum species, which revealed significant variations in secondary metabolites including eugenol, eugenol methyl ether, estragole and methyl cinnamate levels. Expression analysis of eugenol synthase (EGS) gene showed higher transcript levels especially in young leaves and inflorescence; and were positively correlated with eugenol contents. Additionally, transcript levels of coniferyl alcohol acyl transferase, a key enzyme diverting pool of substrate to phenylpropanoids, were in accordance with their abundance in respective species. In particular, eugenol methyl transferase expression positively correlated with higher levels of eugenol methyl ether in Ocimum tenuiflorum. Further, EGSs were functionally characterized from four Ocimum species varying in their eugenol contents. Kinetic and expression analyses indicated, higher enzyme turnover and transcripts levels, in species accumulating more eugenol. Moreover, biochemical and bioinformatics studies demonstrated that coniferyl acetate was the preferred substrate over coumaryl acetate when used, individually or together, in the enzyme assay. Overall, this study revealed the preliminary evidence for varied accumulation of eugenol and its abundance over chavicol in these Ocimum species. Current findings could potentially provide novel insights for metabolic modulations in medicinal and aromatic plants.