In vitro evaluation of the cytotoxicity of pure eugenol

Cytotoxicity, Differentiation, and Biocompatibility of Root-End Filling: A Comprehensive Study

Assessing the biocompatibility of endodontic root-end filling materials through cell line responses is both essential and of utmost importance. This study aimed to the cytotoxicity of the type of cell death through apoptosis and autophagy, and odontoblast cell-like differentiation effects of MTA, zinc oxide-eugenol, and two experimental Portland cements modified with bismuth (Portland Bi) and barium (Portland Ba) on primary cell cultures. Material and methods: The cells corresponded to human periodontal ligament and gingival fibroblasts (HPLF, HGF), human pulp cells (HPC), and human squamous carcinoma cells from three different patients (HSC-2, -3, -4). The cements were inoculcated in different concentrations for cytotoxicity evaluation, DNA fragmentation in electrophoresis, apoptosis caspase activation, and autophagy antigen reaction, odontoblast-like cells were differentiated and tested for mineral deposition. The data were subject to a non-parametric test. Results: All cements caused a dose-dependent reduction in cell viability. Contact with zinc oxide-eugenol induced neither DNA fragmentation nor apoptotic caspase-3 activation and autophagy inhibitors (3-methyladenine, bafilomycin). Portland Bi accelerated significantly (p < 0.05) the differentiation of odontoblast-like cells. Within the limitation of this study, it was concluded that Portland cement with bismuth exhibits cytocompatibility and promotes odontoblast-like cell differentiation. This research contributes valuable insights into biocompatibility, suggesting its potential use in endodontic repair and biomimetic remineralization.

Hematological and Biochemical Responses of Newly Formulated Primary Root Canal Obturating Material: An In Vivo Study

Background and objective Any drug or medicinal agent, when implanted into the body, gets biotransformed by various organ systems and the toxic byproducts of this process alter the normal physiological process. In this experimental study, we aimed to quantify the safety of newly formulated primary root canal obturating material by investigating the hematological and biochemical parameters related to liver function. Methodology Forty-eight Wistar rats (weighing 250-350 grams) were classified into three groups (n=16) through random allocation. Preoperative blood samples were collected by puncturing the orbital venous plexus, the values of which were used as control. Zinc oxide eugenol (ZOE), calcium hydroxide iodoform paste (Metapex), and newly formulated triple antibiotic obturating paste (TAOP) were implanted (100 µg) into dorsal connective tissues. Blood samples on the seventh, 15th, and 30th postoperative days were evaluated respectively by analyzing hematological, hepatic, and, renal function tests for acute and chronic inflammatory responses. Results  The intra-group and inter-group comparisons among all the test materials after seven days exhibited high significance in terms of hemoglobin (Hb), mean corpuscular volume (MCV), neutrophils, and serum glutamic-oxaloacetic transaminase (SGOT) (p<0.001), while others showed mixed responses (p<0.05 to p>0.05). After 15 days, the comparisons showed high significance with respect to packed cell volume (PCV), mean cell volume (MCV), and serum creatinine (p<0.001), while others showed significant to nonsignificant differences (p<0.05 to p>0.05). At the end of 30 days, all the parameters showed mixed responses (p<0.001 to p>0.05). Conclusion The newly formulated obturating material TAOP showed lower adverse hematological, hepatic, and renal effects in experimental animals compared to other test materials, with most parameters reverting to normal after 30 days.

Effect of 4-Allyl-1-hydroxy-2-methoxybenzene (eugenol) in the expression of genes involved in cellular cycle and apoptotic process in dental pulp fibroblasts

OBJECTIVE

This study sought to evaluate the effect of eugenol on the cell morphology and expression of genes involved in the apoptotic process in human dental pulp fibroblasts (hDPFs) from deciduous teeth.

MATERIALS AND METHODS

hDPFs were cultured with 4 concentrations of eugenol (0.06 nM, 0.6 nM, 6 nM, 12 nM) and compared with a control group. After a 72 h incubation period, the cytotoxic effect on cell morphology by optical microscopy and gene expression by RT-PCR were evaluated.

RESULTS

At 0.06 nM and 0.6 nM eugenol concentrations, vacuolisation of the cytoplasm was observed with atypical granulation of the hDPFs, and, at 6 nM and 12 nM cytoplasmic extensions disappeared almost completely. Casp-3, Casp-9, and telomerase genes were not expressed at the concentrations evaluated nor in the control group. The relative expression responses of Bcl-2 and TGF-β genes were overexpressed at the 4 concentrations. MAKP's 0.06 nM (p < .001), 0.6 nM (p < .05) and 12 nM (p < .05) and Cyclin 1 at 12 nM showed significant difference versus the control group (p < .05).

CONCLUSION

Eugenol is capable of causing morphological changes in hDPFs in a dose-dependent manner, higher concentrations may promote overexpression of apoptotic genes.

Pharmacological Properties and Health Benefits of Eugenol: A Comprehensive Review

The biologically active phytochemicals are sourced from edible and medicinally important plants and are important molecules being used for the formulation of thousands of drugs. These phytochemicals have great benefits against many ailments particularly the inflammatory diseases or oxidative stress-mediated chronic diseases. Eugenol (EUG) is a versatile naturally occurring molecule as phenolic monoterpenoid and frequently found in essential oils in a wide range of plant species. EUG bears huge industrial applications particularly in pharmaceutics, dentistry, flavoring of foods, agriculture, and cosmeceutics. It is being focused recently due to its great potential in preventing several chronic conditions. The World Health Organization (WHO) has declared EUG as a nonmutant and generally recognized as safe (GRAS) molecule. The available literature about pharmacological activities of EUG shows remarkable anti-inflammatory, antioxidant, analgesic, and antimicrobial properties and has a significant effect on human health. The current manuscript summarizes the pharmacological characteristics of EUG and its potential health benefits.

Aspirin Eugenol Ester Reduces H2O2-Induced Oxidative Stress of HUVECs via Mitochondria-Lysosome Axis

The oxidative stress of vessel endothelium is a major risk factor of cardiovascular disorders. Antioxidative stress drugs are widely used in cardiovascular therapy. Aspirin eugenol ester (AEE) is a new pharmaceutical compound synthesized by esterification reaction of aspirin with eugenols and possesses antioxidative activity. The present study was designed to investigate the mechanism how AEE protects human umbilical vein endothelial cells (HUVECs) from H₂O₂-induced oxidative stress. H₂O₂ was given to the HUVECs with or without AEE pretreatment. Changes in the oxidative stress-related factors, including those related to the mitochondria-lysosome axis, were determined with Western blotting, cellular immunofluorescence, and enzyme activity test. The results showed that, in the HUVECs, 300 μM H₂O₂ treatment significantly increased the apoptosis rate, MDA concentration, reactive oxygen species (ROS) production, mitochondrial membrane potential, expression of Bax and mature cathepsin D (CTSD), and activity of CTSD and Caspase3 (Cas3) but decreased the expression of Bcl2 and lysosomal membrane stability, while in the HUVECs pretreated with AEE, the above changes caused by either the stimulatory or the inhibitory effect of H₂O₂ on the relevant factors were significantly reduced. AEE pretreatment significantly enhanced the activity of cellular superoxide dismutase and glutathione peroxidase in the HUVECs. Our findings suggest that AEE effectively reduced H₂O₂-induced oxidative stress in the HUVECs via mitochondria-lysosome axis.

Smart textiles in wound care: functionalization of cotton/PET blends with antimicrobial nanocapsules

New antimicrobial pH-responsive wound dressings consisting of immobilized human serum albumin/silk fibroin nanocapsules were developed.

Expansion of Gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: A three-dimensional volumetric study using spiral computed tomography

Aim:

The purpose of this study was to evaluate the three-dimensional expansion of Gutta-percha (GP), at various powder/liquid ratios, of a zinc oxide-eugenol (ZOE)-based sealer using spiral computed tomography (SCT).

Materials and Methods:

Thirty-five freshly extracted human mandibular premolars were selected for this study. Cleaning and shaping were performed in all the teeth initially with hand K-files up to #25 and finally with RaCe rotary instruments (25/06). Teeth were randomly divided into five groups of 7 teeth each. Specimens were scanned using SCT. They were then viewed both cross-sectionally and longitudinally, with a constant thickness of 1 mm/slice. The volume of root canal in each tooth was estimated. Obturation was performed by GP points (25/04) and ZOE-based root canal sealer in all groups with different powder-liquid ratio. Groups 1, 2, 3, and 4, had powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, while in the control group, no sealer was used. The obturation was performed by sealer coated single cone GP. A second SCT scan was performed to determine the volume of GP and sealer in all four groups 1 day after obturation. The third and fourth SCT scans were taken 7 and 30 days after obturation, respectively. The mean volume of GP per group was calculated. Data were statistically analyzed using one-way ANOVA. Inter-group comparisons were done using Scheffe post hoc multiple comparisons test.

Results:

All groups with sealer showed expansion of GP at both 7^th day and 30^th day, which was statistically significant from the GP volume at 1^st day. Groups 2 and 3 with powder/liquid ratio of 1:2 and 1:3 gave the highest mean volume values during 30 days period and showed significant expansion in comparison with Groups 1 and 4 with powder/liquid ratio of 1:1 and 1:4, respectively.

Conclusion:

Increasing the ratio of eugenol in sealer resulted in the volumetric expansion of GP. However, further studies should be performed to confirm the expansion of GP, leading to the achievement of fluid impervious seal.

Antitumor phenylpropanoids found in essential oils

The search for new bioactive substances with anticancer activity and the understanding of their mechanisms of action are high-priorities in the research effort toward more effective treatments for cancer. The phenylpropanoids are natural products found in many aromatic and medicinal plants, food, and essential oils. They exhibit various pharmacological activities and have applications in the pharmaceutical industry. In this review, the anticancer potential of 17 phenylpropanoids and derivatives from essential oils is discussed. Chemical structures, experimental report, and mechanisms of action of bioactive substances are presented.

Expansion of gutta-percha in contact with various concentrations of zinc oxide-eugenol sealer: a three-dimensional volumetric study

INTRODUCTION

Successful endodontic treatment depends on achievement of a fluid-tight seal that is not possible solely with gutta-percha and requires the use of a root canal sealer. Eugenol, which is a principal component in zinc oxide-eugenol (ZOE) based sealers, is reported to produce a volumetric expansion of gutta-percha. The aim of this study was to evaluate the three-dimensional expansion of gutta-percha at various powder/liquid ratios of ZOE-based sealer by using spiral computed tomography (SCT).

METHODS

Fifty freshly extracted premolars with single canal were decoronated and instrumented by using RaCe rotary instruments (35/06). The teeth were divided into 5 groups of 10 each, and volume of the canal was measured by using SCT. The teeth were then obturated with gutta-percha cones (35/04) in groups ZE 1:1 to ZE 1:4 with Pulp Canal Sealer EWT (ZOE-based) with powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, and gutta-percha alone in control group (no sealer group). The filled volume in each canal was measured by using SCT 1 day, 7 days, and 1 month after obturation, and percentages of obturated volume and of volume changes in groups over time were calculated. The data were statistically analyzed by using one-way analysis of variance and post hoc multiple comparison tests.

RESULTS

The groups ZE 1:2 and ZE 1:3 gave the highest mean volume values during a 1-month period and were significantly different in comparison with groups ZE 1:1 and ZE 1:4 (P < .05).

CONCLUSIONS

Increasing the ratio of eugenol in sealer resulted in volumetric increase of gutta-percha. However, further studies should be performed to confirm the expansion and sealing ability of gutta-percha of the size corresponding to the prepared canal, leading to the achievement of fluid impervious seal.

Cytotoxic effect of eugenol on the expression of molecular markers related to the osteogenic differentiation of human dental pulp cells

The cytotoxic effect of eugenol on the expression of molecular markers related to the osteogenic differentiation of human dental pulp cells such as collagen synthesis and the expression of two osteogenesis-related genes, alkaline phosphatase (ALP) and bone sialoprotein (BSP), was studied using human dental pulp cells (D824 cells). Cellular growth and survival were decreased by treatment of cells with eugenol in a concentration-dependent manner. The incorporation rate of [(3)H] proline into the acid-insoluble fraction and the synthesis of type I-V collagens were also reduced by treatment of cells with eugenol in a concentration-dependent fashion. The mRNA expression of ALP was scarcely affected in cells exposed to eugenol, whereas the mRNA and protein expression of BSP was down-regulated depending on the concentrations of eugenol. The results suggest that because collagen synthesis and BSP expression play a critical role in hard tissue formation, eugenol used for endodontic treatment may give rise to cytotoxic effects to the normal function of stem cells reported to exist in human dental pulp tissue and periodontal ligament.

From Natural Products to Polymeric Derivatives of “Eugenol”: A New Approach for Preparation of Dental Composites and Orthopedic Bone Cements

Polymers with eugenol moieties covalently bonded to the macromolecular chains were synthesized for potential application in orthopedic and dental cements. First, eugenol was functionalized with polymerizable groups. The synthetic methods employed afforded two different methacrylic derivatives, where the acrylic and eugenol moieties were either directly bonded, eugenyl methacrylate (EgMA), or separated through an oxyethylene group, ethoxyeugenyl methacrylate (EEgMA). A typical Fisher esterification reaction was used for the synthesis of EgMA and EEgMA, affording the desired monomers in 80% yields. Polymerization of each of the novel monomers, at low conversion, provided soluble polymers consisting of hydrocarbon macromolecules with pendant eugenol moieties. At high conversions only cross-linked polymers were obtained, attributed to participation of the allylic double bonds in the polymerization reaction. In addition, copolymers of each eugenol derivative with ethyl methacrylate (EMA) were prepared at low conversion, with the copolymerization reaction studied by assuming the terminal model and the reactivity ratios determined according to linear and nonlinear methods. The values obtained were r(EgMA) = 1.48, r(EMA) = 0.55 and r(EEgMA) = 1.22, r(EMA) = 0.42. High molecular weight polymers and copolymers were obtained at low conversion. Analysis of thermal properties revealed a T(g) of 95 degrees C for PEgMA and of 20 degrees C for PEEgMA and an increase in the thermal stability for the eugenol derivatives polymers and copolymers with respect to that of PEMA. Water sorption of the copolymers was found to decrease with the eugenol derivative content. Both monomers EgMA and EEgMA showed antibacterial activity against Streptococcus mutans, producing inhibition halos of 7 and 21 mm, respectively. Finally, cell culture studies revealed that the copolymers did not leach any toxic eluants and showed good cellular proliferation with respect to PEMA. This study thus indicates that the eugenyl methacrylate derivatives are potentially good candidates for dental and orthopedic cements.

Interaction between 2-ethoxybenzoic acid (EBA) and eugenol, and related changes in cytotoxicity

The liquid of 2-ethoxybenzoic acid cements is composed of 2-ethoxybenzoic acid and eugenol (4-allyl-2-methoxyphenol). Recently, eugenol was reported to produce radicals at a higher pH, which consequently directly damages cells. We examined here whether eugenol radicals are generated from the mixture of eugenol/calcium hydroxide, and also whether 2-ethoxybenzoic acid or acetylsalicylic acid scavenges radicals, using electron spin resonance spectroscopy. Radicals were generated from the mixture of eugenol/calcium hydroxide in 50% dimethylsulfoxide solution. The radical intensity of eugenol in 50% dimethylsulfoxide with 0.1 M sodium bicarbonate buffer (pH 9.5) was dose-dependently reduced by 2-ethoxybenzoic acid, whereas it was enhanced by acetylsalicylic acid. Next, we investigated the cytotoxic effect of eugenol on 2-ethoxybenzoic acid, acetylsalicylic acid, or calcium hydroxide on human pulp fibroblasts or a human submandibular gland cancer cell line. The cytotoxicity of EBA was decreased, whereas that of acetylsalicylic acid was increased by eugenol. In contrast, that of calcium hydroxide was not affected by eugenol. Human pulp fibroblast but not human submandibular gland cells showed a high resistance against calcium hydroxide. The generation of eugenol radicals in the liquid of 2-ethoxybenzoic acid cements caused by oxidation may be suppressed by 2-ethoxybenzoic acid.

Reaction of bony tissue to implanted silver glass ionomer and a reinforced zinc oxide-eugenol cement

OBJECTIVE

To evaluate the tissue responses to implants of Ketac Silver and Super EBA cement in the guinea pig mandible.

STUDY DESIGN

Sixteen guinea pigs were used for 2 experimental periods of 4 and 12 weeks. Both materials were placed in Teflon applicators and implanted into surgically prepared sites in the mandible. A histologic examination for reaction to the material occurred after the animals were killed and processed.

RESULTS

After 4 weeks, minimal inflammatory reactions were observed in Ketac Silver implants, whereas the Super EBA implants showed minimal to moderate inflammation. Localized foreign body reaction was present in areas of fragmented small particles of Ketac Silver. At 12-weeks observation, no inflammatory reactions were present around either material. Direct bone contact was observed in 1 Ketac Silver implant.

CONCLUSIONS

Ketac Silver and Super EBA cement elicited mild reactions under the conditions of this model. From a biologic point of view, these 2 materials may offer equal utility in endodontic surgery.

Application of bis-eugenol to a zinc oxide eugenol cement

OBJECTIVES

To assess the usefulness of dimerized eugenol (bis-eugenol) in dentistry, the physical properties of zinc oxide eugenol cement (ZOE) with bis-eugenol and the cytotoxicity of bis-eugenol were studied.

METHODS

Setting time, compressive strength, solubility and disintegration of ZOE cement with bis-eugenol according to the specifications of JDMAS315 were evaluated. The cytotoxicity of bis-eugenol and eugenol toward two different cell types, HGF (a primary culture of human gingival fibroblast) and HSG (a human epidermoid carcinoma cell line derived from a salivary gland) was evaluated by the MTT test and in terms of cell survival.

RESULTS

Addition of bis-eugenol to ZOE did not decrease the physical properties when employed at the ratio of 9:1 or 6:1 (liquid ND:bis-eugenol, w/w). Bis-eugenol was less toxic than eugenol in the cell culture tests.

CONCLUSIONS

The results of this assay demonstrated that bis-eugenol is useful in ZOE.

Eugenol diffusion through dentin related to dentin hydraulic conductance

OBJECTIVES

The purpose of this study was (1) to find an easy way of evaluating the concentration of eugenol in cell culture fluids; (2) to confirm the relationship between the concentration and the cytotoxicity of eugenol in vitro; (3) to evaluate the cytotoxicity of four temporary eugenol-based filling materials: IRM, super EBA, Kalsogen and zinc oxide-eugenol cement; and (4) to establish a relationship between dentin permeability, eugenol diffusion and cytotoxicity.

METHODS

(1) The concentration of eugenol was measured with a spectrofluorimeter; (2) the cell viability of L 929 cells cultivated for 24 h with eugenol-containing medium was evaluated by the MTT assay; (3) after measurement of hydraulic conductance, occlusal cavities in human teeth in vitro were filled with the restorative materials. The cytotoxicity was measured with undiluted test medium and with various dilutions in culture medium; (4) after Lp measurement, the eugenol concentration in the media in the pulp chamber that diffused from IRM and 10(3) mol/l eugenol solution was measured.

RESULTS

(1) A proportional relationship (p = 0.001 and r = 1) was found between the concentration of eugenol; (2) eugenol started to be cytotoxic at 10(-5) mol/l and killed 95% of the cells at 10(-3) mol/l; (3) zinc oxide-eugenol cement was the most cytotoxic filling material when tested with the 1:100 dilution; (4) a significant relationship was found between Lp and cytotoxicity (p = 0.04) depending on the dilution of the test medium. A significant relationship was found between Lp and eugenol diffusion from a 10(-3) mol/l solution (p = 0.03) but not between Lp and eugenol diffusing from solid IRM (non significant).

SIGNIFICANCE

Eugenol diffusion from zinc oxide-eugenol cement appears to depend more on the role of hydrolysis of eugenol from zinc oxide-eugenol cement than on dentin permeability.

Dental materials: 1996 literature review

This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.