Re-evaluation of anti-inflammatory potential of eugenol in IL-1ß-stimulated gingival fibroblast and pulp cells.

BACKGROUND: We recently reported that eugenol exerted comparable cytotoxicity towards human normal and tumor cells. In the present study, we investigated the effect of eugenol on interleukin-8 (IL-8) production by IL-1ß-stimulated oral cells. MATERIALS AND METHODS: The viable cell number was determined by direct cell counting with a hemocytometer after trypsinization. IL-8 released into the culture medium was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: IL-1ß (5 ng/ml) induced two orders of magnitude higher production of IL-8 by human cultured cells than unstimulated cells. Upon IL-1ß stimulation, both gingival fibroblasts (HGF) and periodontal ligament fibroblasts (HPLF) produced the greatest amounts of IL-8 (approximately 200-300 ng/ml), followed by pulp cells (HPCs) (approximately 40-50 ng/ml), whereas skin keratinocyte (HaCat) and oral squamous cell carcinoma cells (HSC-2, HSC-4) produced much less IL-8 (less than 15 ng/ml). The production of IL-8 depended on growth factor(s), since the omission of fetal bovine serum from the culture medium resulted in an approximately 90% decline of IL-8 production. Eugenol (5-500 µM) significantly stimulated IL-8 production in HGF cells, but had bi-modal effects on HPCs, causing slight stimulation at lower concentration (5 µM) and a significant inhibition at higher concentration (500 µM), regardless of the presence or absence of serum. Eugenol exerted similar effects on lipopolysaccharide-stimulated HGFs and HPCs. CONCLUSION: These results demonstrate that an anti-inflammatory effect of eugenol is observed in HPCs, but not in HGFs. The narrow therapeutic range of eugenol suggests the importance of careful usage of this compound for dental treatment.

Changes of metabolic profiles in an oral squamous cell carcinoma cell line induced by eugenol.

BACKGROUND: We have recently reported that eugenol exerted indiscriminate cytotoxicity towards normal oral cells and oral squamous cell carcinoma (OSCC) cell lines without induction of apoptosis markers. In order to investigate the underlying mechanisms of cytotoxicity induction, we investigated the effect of short-term treatment with eugenol on the metabolic profiles of a human OSCC cell line (HSC-2). MATERIALS AND METHODS: The viable cell number was determined by direct cell counting with a hemocytometer after trypsinization. After washing with 5% D-mannitol solution (found to retain the highest amounts of intracellular metabolites among several washing conditions), cellular metabolites were extracted with methanol with internal markers and then subjected to metabolomic analysis. RESULTS: Cytotoxic concentrations of eugenol induced the reduction of ATP utilization (assessed by a significant reduction of the AMP/ATP and ADP/ATP ratio), of oxidative stress (assessed by the increase in oxidized form of glutathione, cysteine-glutathione disulfide and methionine sulfoxide), and an increase in the polyamines and glycolytic metabolites. CONCLUSION: The metabolic changes observed in this study suggest the induction of non-apoptotic cell death by eugenol.

Cytotoxicity of dental compounds towards human oral squamous cell carcinoma and normal oral cells.

AIM: The cytotoxicity of four dental compounds, hydroquinone, benzoquinone, eugenol and phtharal towards human oral squamous cell carcinoma (OSCC) cell lines, normal human oral cells (gingival fibroblast, pulp cell, periodontal ligament fibroblast) and skin keratinocytes was investigated. MATERIALS AND METHODS: Viable cell number was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method. The concentration that reduced the viable cells by 50% (CC(50)) and the concentration that increased the viability of UV-irradiated cells to 50% (EC(50)) were determined from the dose-response curves. The tumor-specificity index (TS) was determined by the ratio of the mean CC(50) for normal cells to the one for tumor cells. Apoptosis induction was monitored by assay of internucleosomal DNA fragmentation and caspase-3/-7 activation. RESULTS: When both oral OSCC and normal oral cells were incubated for 4 h with any of hydroquinone, benzoquinone, eugenol and phtharal, irreversible cell growth inhibition, accompanied by cell death occurred without induction of apoptotic markers, although caspase-3/-7 activation was observed at 6 h or later. These compounds exhibited very low tumor-specificity (TS=0.4-1.3), as compared with anticancer drugs (5-fluorouracil, melphalan, peplomycin) (TS=4.1-9.7). Human skin keratinocytes were the most resistant to these drugs, and a long incubation time was required to induce irreversible growth inhibition. However, all dental compounds exhibited very low tumor-specificity (TS=0.4-2.4), compared to human skin keratinocytes and OSCC cell lines. None of the dental compounds exhibited any hormetic growth stimulation, nor protected the cells from UV-induced damage. CONCLUSION: These results suggest that apoptosis is not involved in the early stage of growth inhibition induced by dental compounds.

Anti-UV activity of lignin-carbohydrate complex and related compounds.

BACKGROUND: We recently reported that an alkaline extract of the leaves of Sasa senanensis Rehder (SE) and Lentinus edodes mycelia extract (LEM), exhibiting lignin-carbohydrate complex (LCC)-like activity, protected cells from UV-induced injury (referred to as anti-UV activity). We investigated whether LCC is the major active components responsible for anti-UV activity. MATERIALS AND METHODS: Human oral squamous cell carcinoma HSC-2 cells were exposed to short UV irradiation in phosphate-buffered saline, containing different concentrations of LCC. After culturing for 48 h in fresh culture medium, the viable cell number was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. From the dose-response curve, the 50% cytotoxic concentration (CC(50)) and the concentration that increased the viability of the UV-irradiated cells to 50% of the control value (EC(50)) were determined. The selectivity index (SI) was determined by the following equation: SI=CC(50)/EC(50). RESULTS: LCCs (Fr. VI) of pine cones and seed shell, and sulfated LCC exhibited relatively high anti-UV activity (SI=7.1-38), compared with that of SE and LEM. LCCs with lower lignin content (Fr. VII) exhibited anti-UV activity, approximately one half that of Fr. VI. However, polysaccharides (laminarin, pullulan, dextran) introduced with dimethylaminoethyl- or sulfate groups with different substitution ratios were totally inactive (SI<1). The introduction of a sulfate group to LCC did not enhance the anti-UV activity of LCC. Sodium ascorbate and vanillin were the most active (SI=65), whereas gallic acid (SI=5), epigallocatechin gallate (SI=2.6), ar-trumeron (SI<1), and turmeric extract (SI<1) were much less active. CONCLUSION: The prominent anti-UV activity of SE and LEM seems to be generated by LCCs present in the extract.

Comparative inhibitory effects of magnolol, honokiol, eugenol and bis-eugenol on cyclooxygenase-2 expression and nuclear factor-kappa B activation in RAW264.7 macrophage-like cells stimulated with fimbriae of Porphyromonas gingivalis.

BACKGROUND: The anti-inflammatory activity of magnolol and related compounds is currently a focus of interest. In the present study, the inhibitory effects of these compounds on cyclooxygenase (COX-2) expression and nuclear factor-kappa B (NF-κB) activation were investigated in RAW264.7 macrophage-like cells stimulated with the fimbriae of Porphyromonas gingivalis, an oral anaerobe. MATERIALS AND METHODS: The cytotoxicity of magnolol, honokiol, eugenol and bis-eugenol against RAW264.7 cells was determined using a cell counting kit (CCK-8). The regulatory effect of these compounds on the expression of COX-2 mRNA, stimulated by exposure to the fimbriae was investigated by real-time polymerase chain reaction (PCR). NF-κB activation was evaluated by enzyme-linked immunosorbent assay (ELISA)-like microwell colorimetric transcription factor activity assay (Trans-AM) and western blot analysis. The radical-scavenging activity was determined using the induction period method in the methyl methacrylate-azobisisobutyronitrile (AIBN) polymerization system under nearly anaerobic conditions. The phenolic bond dissociation enthalpy (BDE) and orbital energy were calculated at the density functional theory (DFT) B3LYP/6-31G* level. RESULTS: The cytotoxicity against RAW264.7 cells declined in the order bis-eugenol>eugenol> honokiol>magnolol, whereas the radical-scavenging activity declined in the order honokiol, bis-eugenol>magnolol> eugenol. Magnolol and honokiol significantly inhibited the fimbria-induced expression of COX-2 at non-cytotoxic concentrations. Both the fimbria-stimulated binding of NF-κB to its consensus sequence and phosphorylation-dependent proteolysis of inhibitor κB-α were markedly inhibited by magnilol and honokiol, whereas eugenol and bis-eugenol did not inhibit COX-2 expression and NF-κB activation. Magnolol and honokiol possessed a high electronegativity (χ) value. CONCLUSION: Magnolol and honokiol exhibit antioxidative activity, low cytotoxicity, and anti-inflammatory activity. These compounds may be capable of preventing chronic inflammatory diseases induced by oral bacteria.

Pilot clinical study of Sasa senanensis Rehder leaf extract treatment on lichenoid dysplasia.

BACKGROUND: Previous studies have shown antiviral, antibacterial, and anti-inflammatory activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE). Here, we investigated whether SE is effective on oral lichenoid dysplasia and osteoclastogenesis. MATERIALS AND METHODS: A male patient with white lacy streaks in the oral mucosa was orally administered SE three times a day for 11 months. The area of white streaks was monitored by intraoral photography. Interleukin-6 and -8 in the saliva were determined by enzyme-linked immunosorbent assay. Osteoclastogenesis of mouse macrophage-like RAW264.7 cells, induced by receptor activator of nuclear factor-κB ligand (RANKL) was monitored by tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cell formation. RESULTS: Long-term treatment with SE progressively reduced both the area of white steaks and the levels of salivary interleukin-6 and -8. SE significantly inhibited the macrophage differentiation towards osteoclasts. CONCLUSION: The present study suggests the therapeutic potential of SE towards oral diseases.

Pilot study of changes in salivary metabolic profiles induced by template therapy.

BACKGROUND: Occlusal raising method (so-called 'Template therapy') has been reported to alleviate various diseases and symptoms, but the underlying mechanism is not clear. We searched the low-molecular weight metabolite(s) in the saliva, the concentration of which is significantly changed by the template therapy. MATERIALS AND METHODS: One female patient with headache underwent the template therapy for 12 days, and her total saliva was subjected to non-targeted analysis using capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS). RESULTS: One hundred and thirteen substances were identified in the saliva. Glycine was the most abundant amino acid in the saliva, followed by alanine, serine and proline. After the start of the template therapy, her headache was alleviated, accompanied by a significant (p=0.042) increase of salivary concentration of glycine, as compared with total amino acids whereas that of other amino acids was not significantly changed. In the metabolomics profile, salivary concentration of large number of metabolites as compared with total metabolite concentration decreased, including N-acetylneuraminate (p=0.025) and p-hydroxyphenylacetate (p=0.039). CONCLUSION: This pilot study demonstrated, to our knowledge for the first time, that only glycine exhibited unique changes among total metabolites, suggesting its significant role in template therapy.

Effects of curcumin and capsaicin irradiated with visible light on murine oral mucosa.

The purpose of this study was to evaluate the histopathological effects of curcumin and capsaicin, with or without visible light (VL) irradiation for 5 min, on the oral mucous membrane in mice. Capsaicin-treated, but not curcumin-treated, buccal epithelium exhibited slight tissue damage; VL irradiation caused excessive tissue damage, particularly when combined with the former treatment. The TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method demonstrated that both capsaicin and curcumin induced apoptosis, with the apoptotic effect of capsaicin appearing at an early stage of application. VL irradiation increased the number of apoptotic cells, particularly those upon in the capsaicin-treated area. Capsaicin and curcumin acted as photosensitizers exposure to VL, in the presence of oxygen. Curcumin and capsaicin with VL irradiation could thus be used for photodynamic therapy in the clinical setting, especially in precancerous oral diseases.

Effect of three fluoride compounds on the growth of oral normal and tumor cells.

AIM: Comparative study of the growth inhibition by different types of fluoride compounds used in dentistry has been limited. We investigated the effects of sodium fluoride (NaF), diammine silver fluoride [Ag(NH3)2F] and 5-fluorouracil (5-FU) on the growth of eleven human normal and tumor cells in total. MATERIALS AND METHODS: Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis induction was evaluated by caspase-3 activation and DNA fragmentation. Fluoride was determined using a fluoride-specific electrode. RESULTS: All compounds had little or no growth stimulating effect (hormesis) on all cells. Ag(NH3)2F exhibited the highest cytotoxicity towards both normal and tumor cells. 5-FU had the selective cytostatic activity towards oral squamous cell carcinoma cell lines, whereas NaF was selectively cytotoxic towards glioblastoma cell lines. None of the compounds induced internucleosomal DNA fragmentation and only 5-FU induced slight activation of caspase-3 in an oral squamous cell carcinoma cell line (HSC-2). Cytotoxicity of fluoride compounds was not reduced by superoxide dismutase and catalase, reducing the possibility of the involvement of reactive oxygen species in the mechanism of action. Approximately 0.01-0.09% initially added NaF was recovered from the cells, whereas the cellular uptake of Ag(NH3)2F and 5-FU was below the detection limit. CONCLUSION: Cytotoxicity of fluoride compounds may not be directly linked to their tumor specificity nor to their apoptosis-inducing activity.

Porphyromonas gingivalis Fimbria-Induced Expression of Inflammatory Cytokines and Cyclooxygenase-2 in Mouse Macrophages and Its Inhibition by the Bioactive Compounds Fibronectin and Melatonin.

Porphyromonas gingivalis (Pg) fimbriae, in addition to lipopolysaccharide, are involved in the pathogenesis of periodontal disease. At the same time, bioactive compounds such as fibronectin (FN) and melatonin in saliva and gingival crevicular fluid have been reported to exert a preventive effect against periodontitis. Here, we review current knowledge regarding the potent inhibitory effects of FN and melatonin against Pg fimbria-induced induction of proinflammatory cytokines, cyclooxygenase-2 (COX-2) expression, and NF-kappa B activation in mouse macrophages and discuss their possible clinical application for prevention of periodontal diseases induced by oral bacteria.

Effect of melatonin on cyclooxygenase-2 expression and nuclear factor-kappa B activation in RAW264.7 macrophage-like cells stimulated with fimbriae of Porphyromonas gingivalis.

BACKGROUND: The possible link between melatonin and anti-inflammatory activity is currently a focus of interest. In the present study, COX-2 expression and NF-κB activation in RAW264.7 macrophage-like cells stimulated with the fimbriae of Porphyromonas gingivalis, an oral anaerobe, in the absence and presence of melatonin were investigated. MATERIALS AND METHODS: The cytotoxicity of melatonin and indole against RAW264.7 cells was determined using a cell counting kit. The regulatory effect of melatonin, and of indole on the expression of COX-2 mRNA stimulated by exposure to the fimbriae was investigated by Northern blot analysis. NF-κB activation was evaluated by both electrophoretic mobility-shift assay and Western blot analysis. RESULTS: The half maximal (50%) effective concentration (EC(50)) values for melatonin and indole were 3300 µM and 130 µM, respectively. Melatonin at non-cytotoxic concentrations significantly inhibited the fimbria-induced expression of COX-2. The fimbria-stimulated binding of NF-κB to its consensus sequence and phosphorylation-dependent proteolysis of inhibitor κB-α were markedly inhibited by melatonin. However, indole did not inhibit COX-2 expression and NF-κB activation. CONCLUSION: Melatonin may be able to prevent diseases induced by oral bacteria.

Changes in salivary amino acid composition during aging.

BACKGROUND: it has been suggested that the features of saliva reflect the physiological and psychological state of primates as well as subprimates, however, studies revealing the relationship between aging and the concentrations of salivary amino acids are limited. In order to better understand their physiological role, age-related changes of salivary amino acids were investigated. MATERIALS AND METHODS: forty-five participants including 5 children [6.60 ± 1.67 (5-9) years old], 20 adults [46.55 ± 14.68 (23-64) years old), and 20 senior citizens [71.60 ± 4.27 (66-82) years old] took part in this study. Whole saliva (one sample per each person) was collected in the daytime (10:00-11:00 or 14:00-15:00). Salivary amino acids were recovered after deproteinization with 5% trichloroacetic acid and determined by an amino acid analyzer. RESULTS: glycine was the most abundant amino acid in the saliva. Glycine and lysine levels increased significantly (p<0.05) with aging, regardless of gender difference. When the glycine and lysine levels were plotted, much higher correlation (p<0.001) was observed. On the other hand, there was no significant correlation between the salivary concentration of glutamic acid or histidine and age. CONCLUSION: salivary amino acid levels may be regarded as markers of aging.

Multiple biological complex of alkaline extract of the leaves of Sasa senanensis Rehder.

Previous studies have shown anti-inflammatory potential of alkaline extract of the leaves of Sasa senanensis Rehder (SE). The aim of the present study was to clarity the molecular entity of SE, using various fractionation methods. SE inhibited the production of nitric oxide (NO), but not tumour necrosis factor-α by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells. Lignin carbohydrate complex prepared from SE inhibited the NO production to a comparable extent with SE, whereas chlorophyllin was more active. On successive extraction with organic solvents, nearly 90% of SE components, including chlorophyllin, were recovered from the aqueous layer. Anti-HIV activity of SE was comparable with that of lignin-carbohydrate complex, and much higher than that of chlorophyllin and n-butanol extract fractions. The CYP3A inhibitory activity of SE was significantly lower than that of grapefruit juice and chlorophyllin. Oral administration of SE slightly reduced the number of oral bacteria. When SE was applied to HPLC, nearly 70% of SE components were eluted as a single peak. These data suggest that multiple components of SE may be associated with each other in the native state or after extraction with alkaline solution.

Radical-scavenging activity and cytotoxicity of p-methoxyphenol and p-cresol dimers.

Compoundswith two phenolic OH groups like curcumin possess efficient antioxidant and anti-inflammatory activity. We synthesized p-cresol dimer (2,2'-dihydroxy-5,5'-dimethylbiphenol, 2a) and p-methoxyphenol dimer (2,2'-dihydroxy-5,5'-dimethoxybiphenol, 2b) by ortho-ortho coupling reactions of the parent monomers, p-cresol (1a) and p-methoxyphenol (1b), respectively. Their antioxidant activity was determined using the induction period method, and their cytotoxicity towards RAW 264.7 cells was also investigated using a cell counting kit. The stoichiometric factors n (number of free radicals trapped by one mole of antioxidant moiety) for 2a and 2b were 3 and 2.8, respectively, being greater than those for 1a and 1b. The ratio of the rate constant of inhibition to that of propagation (k(inh)/k(p)) for 2a and 2b was similar to that for 2-t-butyl-4-methoxyphenol (BHA), a conventional food antioxidant. The 50% inhibitory dose (ID50) declined in the order 1b > 1a >> 2b > 2a > BHA. The cytotoxicity for 2a and 2b was significantly greater than that for the parent monomers (p < 0.001), but smaller than that for BHA (p < 0.01). Compounds 2a and 2b may be useful as food antioxidants.

Antioxidant and cyclooxygenase-2-inhibiting activity of 4,4'-biphenol, 2,2'-biphenol and phenol.

The anthropogenic substance 4,4'-biphenol and its analogues are estrogenic and cytotoxic. It has been previously found that synthesized ortho-dimers of phenolic compounds possess potent antioxidative and anti-inflammatory activity. To clarify the relationships between radical-scavenging and anti-inflammatory activities, the radical-scavenging activities of 4,4'-biphenol, 2,2'-biphenol and phenol were investigated by using differential scanning calorimetry to measure the induction period for polymerization of methyl methacrylate initiated by thermal decomposition of 2,2'-azobisisobutyronitrile. We also investigated tThe inhibitory effects of these compounds on lipopolysaccharide (LPS)-stimulated cyclooxygenase-2 (COX-2) mRNA and protein expression and on binding of activator-protein-1 (AP-1) and nuclear factor kappa-B (NF-kappaB) to their respective consensus sequences were also investigated in RAW 264.7 cells. Furthermore, theoretical parameters such as phenolic-OH bond dissociation enthalpy (BDE) and ionization potential (IP(koopman)) were calculated at the density functional theory (DFT)/B3LYP levels. Cytotoxicity declined in the order 4,4'-biphenol > 2,2'-biphenol >> phenol. 2,2'-Biphenol, but not 4,4'-biphenol, showed inhibitory effects on LPS-stimulated COX-2 expression and on AP-1 and NF-kappaB binding to their consensus sequences at 1-10 muM. Expression of COX-2 in RAW cells was enhanced by 4,4'-biphenol plus LPS, possibly because of radical-mediated transformation of 4,4'-biphenol to the cytotoxic diphenylquinone, as judged by the stoichiometric factor (n value) of 3.429 and low IP(koopman) value of this biphenol. In contrast, the anti-inflammatory activity of 2,2'-biphenol may be the result of the formation of a dimer derived from oxidation of this compound, as suggested by its n value close to 1. Phenol showed anti-inflammatory activity but did not completely inhibit COX-2 expression, even at higher concentrations.

The relationship of Prevotella intermedia, Prevotella nigrescens and Prevotella melaninogenica in the supragingival plaque of children, caries and oral malodor.

PURPOSE: A relationship between the distribution of periodontal bacteria species and malodor in children has not been sufficiently investigated. The present study was undertaken to determine the presence of 3 periodontopathic bacteria (Prevotella spp. P. intermedia, P. nigrescens, P. melaninogenica) in the supragingival plaques of 3 to 16-year-old children with different oral health conditions and oral malodor. METHODS: The number of decayed and filled primary teeth (df) and Decayed, Missing and Filled permanent teeth (DMF), Papillary Marginal and Attached gingivitis (PMA) index, Oral Hygiene Index (OHI), and oral malodor of each subject were determined prior to the collection of supragingival plaques. Three periodontopathic bacteria (P. intermedia, P. nigrescens, P. melaninogenica) in supragingival plaques were detected by using an immunoslot blot assay with monoclonal antibodies specific for each microorganism. FINDINGS: The frequencies of periodontopathic bacteria in children with and without caries were not significantly different from each other. Positivity for P. intermedia, but not for P. nigrescens or P. melaninogenica was correlated with oral malodor. Oral malodor was also correlated with the debris index, a component of OHI. The group with the higher OHI showed a higher prevalence of periodontopathic bacteria. For the 3 periodontopathic bacteria in the subjects tested, plaques positive for any of them were not age related. However the frequencies of all 3 periodontopathic bacteria were the highest in the 3-6-year olds. CONCLUSION: The supragingival plaques in children can harbor 3 species of periodontopathic bacteria, P. intermedia, P. nigrescens, and P. melaninogenica.

Comparative anti-inflammatory activities of curcumin and tetrahydrocurcumin based on the phenolic O-H bond dissociation enthalpy, ionization potential and quantum chemical descriptor.

Curcumin and its reduced derivative tetrahydrocurcumin have been shown to exhibit chemopreventive activity. Cyclooxygenase-2 (COX-2) inhibition in lipopolysaccharide (LPS)- or Porphyromonas gingivalis fimbria-stimulated RAW 264.7 cells was investigated using Northern blot analysis. The fimbria-stimulated expression of the COX-2 gene was inhibited by curcumin but not by tetrahydrocurcumin. LPS-stimulated COX-2 gene expression was completely inhibited by curcumin, but an increase in the concentration of tetrahydrocurcumin did not cause complete inhibition of COX-2 expression. The inhibitory effect of curcumin on nuclear factor kappa B (NF-kappaB) activation in the cells was clearly observed, but that of tetrahydrocurcumin was incomplete even at a concentration of 20 microM. To explain the difference in effect between the two compounds, analysis of the frontier orbital was performed using ab initio 6-31G* wave function. The calculated chemical hardness (eta) for curcumin was clearly smaller, whereas its electronegativity (chi) and electrophilicity (omega) were clearly greater than the corresponding values for the curcumin-related compounds tetrahydrocurcumin, isoeugenol and eugenol. This suggested that the anti-inflammatory activities of curcumin may be related to eta-, chi- and/or omega-controlled enzymes. In addition, the bond dissociation enthalpy (BDE) of the phenolic OH was calculated using the density function theory (DFT)/B3LY. The total BDE values of curcumin and tetrahydrocurcumin were almost identical, but the BDE of one-electron oxidation and ionization potential (IP) for curcumin were lower than those for tetrahydrocurcumin, suggesting the highly pro-oxidative activity of curcumin. Curcumin has both oxidant and antioxidant properties. A causal link between the anti-inflammatory activities and molecular properties of phenolic antioxidants is suggested.

Effects of visible light-irradiated camphorquinone and 9-fluorenone on murine oral mucosa.

The purpose of this study was to evaluate the histopathological effects of camphorquinone (CQ) and 9-fluorenone (9F) with or without visible light (VL) irradiation on the oral mucous membranes of mice. VL irradiation resulted in a higher degree of tissue damage after CQ or 9F application, particularly the latter. Necrosis and apoptosis were responsible for the tissue damage after application of either agent in the presence of VL irradiation.

Re-evaluation of cyclooxygenase-2-inhibiting activity of vanillin and guaiacol in macrophages stimulated with lipopolysaccharide.

Phytophenols such as para-substituted 2-methoxyphenols exhibit antioxidant and anti-inflammatory activities, however, their biological activities are concentration-dependent, possibly due to their dual property of being both antioxidant and prooxidant. Eugenol (2-allyl-2-methoxyphenol) and isoeugenol (4-propenyl-2-methoxyphenol) did not reveal cyclooxygenase-2 (COX-2)-inhibiting activity in macrophages stimulated with lipopolysaccharide (LPS). In contrast, vanillin (2-hydroxy-3-methoxybenzaldehyde) and guaiacol (2-methoxyphenol), especially the former, inhibited LPS-stimulated nuclear factor kappa B (NF-kappaB) activation and cyclooxygenase (COX)-2 gene expression in cells of the RAW 264.7 murine macrophage cell line. Among the 2-methoxyphenols, vanillin demonstrated a potent anti-inflammatory activity. The phenolic O-H bond dissociation enthalpy (BDE) and molecular orbital energies (chemical hardness [eta], electronegativity [chi], and electrophilicity [omega]) were examined to clarify the mechanism responsible for inhibition of COX-2 expression. The BDE, chi, and omega values for vanillin were significantly higher than the corresponding values for the other 2-methoxyphenols. The anti-inflammatory activity of 2-methoxyphenols depended on the BDE and the phenol function was crucial for eliciting this activity. In addition, the anti-inflammatory activity depended on the chi and omega. These findings make vanillin attractive as a candidate therapeutic agent.

Re-evaluation of antitumor activity of Cepharanthin.

The antitumor potential of Cepharanthin was re-evaluated. Cepharanthin, a biscoclaurin alkaloid extracted from Stephania cepharantha Hayata, dose-dependently reduced the viable cell number of both normal and tumor cells, showing no tumor-specific cytotoxic action. Cepharanthin synergistically enhanced the cytotoxic activity of vitamin K3 and epigallocatechin gallate. Cepharanthin induced internucleosomal DNA fragmentation only in the human promyelocytic leukemic cell line HL-60. ESR spectroscopy showed that Cepharanthin effectively scavenged the superoxide anion (produced by hypoxanthine-xanthine oxidase reaction), the hydroxyl radical (produced by Fenton reaction) and nitric oxide (NO) (produced by NOC-7 in the presence of C-PTIO). The radical scavenging activity of Cepharanthin suggests its possible anticarcinogenic action. Cepharanthin dose-dependently inhibited the production of nitric oxide, but not that of tumor necrosis factor by lipopoysaccharide-stimulated mouse macrophage-like cells Raw 264.7. These data present a cautionary note that the cytotoxic activity of Cepharanthin is more prominent than its immunopotentiating activity.