Concentrations Of Eugenol Research Articles

Effect of Eugenol on Gastric Function in Rats.

Eugenol, an active principle of clove, is an effective secretagogue in rats, causing dose-dependent augmentation of gastric secretion. Eugenol, when administered intragastrically at 100μg/kg body weight, stimulated maximum secretion of gastric free acid and serum pepsinogen. However, at higher concentrations it had an inhibitory effect on gastric secretion. Long-term oral treatment with eugenol at a dose of 100μg/kg body weight per day for three weeks significantly increased the serum pepsinogen levels, which positively correlated with gastric free acid secretion. The levels of serum mucoprotein and α-antitrypsin remained unchanged. Histopathological examination of the stomach of experimental animals did not show any damage to mucosal cells. Thus, stimulation of gastric secretion at a low concentration of eugenol, i. e., 100μg/kg body weight and below, should facilitate digestion.

Eugenol Induced Inhibition of Extracellular Enzyme Production by Bacillus subtilis

Eugenol, the major essential oil of clove, in sublethal concentrations (0.02–0.03%, v/v) inhibited the production of alpha-amylase, protease, and subtilisin by Bacillus subtilis in laboratory media. Microscopic observations revealed that at these eugenol concentrations, B. subtilis cells appeared swollen and distorted and/or appeared as very long and thin filaments (> 100 μm). Of 20 amino acids investigated, only L-glutamic or L-aspartic acid (>5.0 mg/ml) prevented such morphogenic distortions when added to eugenol-containing media before inoculation. Addition of these amino acids also resulted in an increase in biomass and protease production. In contrast, the addition of serine (> 1.0 mg/ml) enhanced filamentous growth but reduced the production of protease and subtilisin.

Acute inhalation toxicity of eugenol in rats.

The acute toxicity of inhaled eugenol was assessed by exposure of three groups of five male and five female rats to a submicron aerosol of eugenol for 4 h followed by a 14-day observation period. A fourth group, also of five male and five female rats and exposed to air only under similar conditions, served as a control group for comparison. The three concentrations of eugenol to which the different groups were exposed were 2.58, 1.37 and 0.77 mg/l. The mass median aerodynamic diameters and geometric standard deviations of the aerosols were, respectively, 0.82 micron (sigma g 2.26), 0.88 micron (sigma g 2.05) and 0.9 micron (sigma g 1.87). Clinical signs observed during exposure consisted principally of moderately increased salivation and restlessness (indicative of irritation) and abnormal breathing patterns. The signs were graded, being less marked in animals exposed to the lower concentrations of eugenol. All three groups, exposed to high, medium and low levels of eugenol, lost weight overnight following exposure. Associated with the weight loss were marked reductions in food and water intake. The responses appeared to be largely independent of the concentration of eugenol inhaled, although there was some evidence of a graded effect on water intake. There was rapid recovery, with food and water consumption data comparable with control values throughout most of the remainder of the 14-day observation period. Also, by the end of the observation period, group mean body weights were comparable. Upon sacrifice and macroscopic examination of the animals, abnormalities were detected in the lungs only of a few animals: 3/10 control, 2/10 eugenol 2.58 mg/l, and 2/10 eugenol 0.77 mg/l.(ABSTRACT TRUNCATED AT 250 WORDS)

DIfferential inhibition of A, B and C fibres in the rat vagus nerve by lidocaine, eugenol and formaldehyde

Evoked compound-action potentials (cAP) in all three fibre types of the isolated nerve were reversibly depressed by exposure to the drugs. After 20 min exposure, lidocaine (0.5 mM) depressed the amplitude of the A and B fibre potentials significantly more than the C fibre potential. With eugenol (0.8 mM), there was no significant difference in depression of A, B and C fibre activity. With formaldehyde (4.5 mM), the latency was longer, and the C fibres were initially significantly more depressed than the A and B fibres. As dull pain from a chronically-inflamed pulp is believed to be mediated through C fibres, these results may explain the difficulties in obtaining complete local analgesia with lidocaine. They indicate that application of low concentrations of eugenol and formaldehyde to the pulp-dentine organ may have an analgesic effect on pain mediated through both A and C fibres.

Effect of eugenol on respiration and division in human pulp, mouse fibroblasts, and liver cells in vitro.

Eugenol depressed cell respiration in homogenates of human dental pulp and in mouse fibroblast monolayers. The depression was concentration-dependent, with a threshold at about 10(-4)M and a maximum at 10(-3)M in both preparations. Onset of the depression appeared to be rapid. The effects of variation in both duration and concentration of eugenol exposure on subsequent uptake of 3H-thymidine were examined in mouse fibroblast monolayers and human pulp explants. Fibroblasts survived short-term (up to 12 hr) exposure to 10(-3)M eugenol or less, but died after exposure to 10(-3)M for one day or more. The cells survived exposure to 10(-4)M for ten days, the longest period examined. Human pulp maintained in tissue culture medium showed similar eugenol susceptibility. Analysis of these data, when coupled with those of previous studies on eugenol release from ZOE and diffusion through dentin, gives strong support for the concepts that: the blandness of ZOE when applied to intact dentin is due to eugenol reaching the pulp in sub-toxic concentrations, and the irritant effect of ZOE when applied directly to soft tissue is due to the development of concentrations of eugenol in tissue adjacent to ZOE sufficient to inhibit respiration and thus kill cells.

An analysis of the release and the diffusion through dentin of eugenol from zinc oxide-eugenol mixtures.

Tritium-labeled eugenol was released from mixtures of zinc oxide eugenol (ZOE) into aqueous solution at rates which declined exponentially with time, and which were directly proportional to the liquid-powder ratio. The release pattern was consistent with a model of progressive hydrolysis of zinc eugenolate in a limited-thickness ZOE surface layer. Intervening dentin had a profound effect on this pattern of release. In human teeth in vitro containing ZOE as a base or temporary filling, peak eugenol release at the pulpal surface of dentin was of the order of a thousand-fold less than that at the salivary surface. In such teeth, eugenol reached concentrations in excess of 10(-2) M in dentin just beneath ZOE, and 10(-4) M or less adjacent to the pulp space. Both pulpal outflow and dentin concentrations of eugenol remained relatively constant for more than a week, unlike release into aqueous solution. While these data were derived from studies on human teeth in vitro, they give a strong indication of probable events in vivo, and appear to provide a basis for the explanation of the paradox of the therapeutic and toxic actions of ZOE.

Eugenol and clove leaf oil: A survey of consumer patch-test sensitization

The potential of eugenol and of clove leaf oil, which contains a high concentration of eugenol, to induce delayed skin hypersensitivity or to elicit reactions due to pre-existing skin sensitization in man was evaluated by analysing patch-test data. Results from a total of 11,632 patch tests on eugenol itself, on various consumer products containing eugenol and/or clove leaf oil, and on fragrance blends containing eugenol and/or clove leaf oil were collected from fragrance and formulation companies. One instance of induced hypersensitivity and one instance of pre-existing sensitization were observed at eugenol patch-test concentrations of 5 × 10−2 and 9 × 10−2% respectively. In both cases, subsequent patch testing showed skin responses to mixtures of eugenol and isoeugenol, but no further attempt was made to define the causative agent. The survey indicates that, at the concentrations present in consumer products, eugenol alone or as part of clove leaf oil has a very low potential either to elicit pre-existing sensitization (‘elicited’ reactions) or to induce hypersensitivity (‘induced’ reactions).

Eugenol, a New Attractant for the Northern Corn Rootworm (Coleoptera: Chrysomelidae)1

Eugenol, a component of the best commercially available, food-type lure for Japanese beetles, Popillia japonica Newman, was attractive to adults of the northern corn rootworm (NCR), Diabrotica barberi Smith and Lawrence. Captures of NCR increased significantly as concentrations of eugenol in traps increased, and more beetles were attracted to eugenol-baited traps placed outside of a cornfield than to traps placed within the field. Adult western corn rootworms, Diabrotica virgifera virgifera Le Conte, which feed almost exclusively on corn, were not attracted to eugenol. Attraction of NCR to eugenol, a compound distributed widely in the plant kingdom, may indicate the extent to which NCR is adapted to feed on hosts other than corn.

The effect of eugenol on nerve transmission

Because of its long-time use as a sedative or anodyne in dental procedures, eugenol was studied to determine its effect on evoked nerve impulse transmission. The sciatic nerve of the bullfrog was stimulated in a nerve chamber, and the compound action potential was visualized on and recorded from an oscilloscope screen. It was determined that eugenol concentrations ranging from 100 per cent to 0.01 per cent extinguished the impulse-transmission capabilities of the nerve within 3 hours. No reversal was observed within this time frame.

The Role of Phenolics and Abscisic Acid in Nutsedge Tuber Dormancy

The phenolic content of purple nutsedge (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.) was determined. The major phenolic components were p-coumaric, ferulic, p-hydroxybenzoic, syringic, vanillic, salicylic, proto-catechuic, and caffeic acids, and eugenol. High concentrations of eugenol and salicylic acid inhibited the sprouting of nutsedge tubers. The lack of activity at lower concentrations argues against a major role for these compounds in maintaining nutsedge tuber dormancy. Exogenous abscisic acid inhibited nutsedge tuber sprouting and may be a natural dormancy factor in nutsedge.

Inheritance and Flavor Contribution of 2-Isobutylthiazole, Methyl Salicylate and Eugenol in Tomatoes1

Abstract The volatile compounds of tomato cultivars ‘Campbell 146’ and ‘Campbell 1327’ were studied by gas-liquid chromatography. Heritable concentration differences were found for 3 compounds identified by retention time and infrared spectroscopy as 2-isobutylthiazole, methyl salicylate and eugenol. Investigation of concentrations and flavor thresholds indicated that they probably contribute to tomato flavor. A study of the inheritance of the 3 compounds indicated that 2-isobutylthiazole concentration was determined by a single gene with additive effects. Concentrations of methyl salicylate and eugenol were determined by single genes closely linked in the coupling phase, with dominance for low concentration.