Probiotics study with Streptococcus salivarius and its ability to produce bacteriocins and adherence to KB cells / Estudo de probióticos Streptococcus salivarius e sua habilidade de produzir bacteriocinas e aderência à células KB

Abstract Introduction Streptococcus salivarius is a dominant oral species and the best suitable candidate for probiotic of the oral cavity. Since Streptococcus salivarius is able to produce bacteriocins against Streptococcus pyogenes interest has been focused on the use of it as a probiotic to avoid sore throats by Streptococcus pyogenes. Objective This study is for selecting Streptococcus salivarius strains for potential use as probiotics for the oral mucosa, that is, production of bacteriocin against Streptococcus pyogenes and the ability to bind to KB cells. Material and method Tongue material from 45 students was collected and seeded on Mitis Salivarius Agar plaques. The strains were tested by the production of bacteriocin-like substances (BLIS) against S. pyogenes, biochemically and PCR for identification of S. salivarius. The best strains were tested for adherence to KB cells. Briefly, S. salivarius strains were cultured in broth, washed and suspended at 108cells/ml. KB cells were inoculated into plaques, washed and incubated with the bacteria, for adhesion. These were washed for lysis of the KB cells and release bacteria for determination of CFU. Result The bacteriocin test showed that 133 strains presented inhibition of S. pyogenes. The samples tested for adhesion to KB cells, presented different profiles and only three strains presenting high adhesion capacity. Conclusion The selection of strains of Streptococcus salivarius with high inhibitory activity against Streptococcus pyogenes, as well as adherence to KB cells leads us to the next future step, that is, to use the best strains for in vivo colonization tests

Resumo Introdução Streptococcus salivarius é uma espécie dominante na cavidade bucal e tem sido indicada como um ótimo candidato para uso como probiótico. Visto que a espécie Streptococcus salivarius é capaz de produzir bacteriocinas contra Streptococcus pyogenes, desenvolveu-se interesse no uso desse microrganismo como probiótico, para evitar amigdalites causadas por Streptococcus pyogenes. Objetivo A pesquisa em questão tem o objetivo de selecionar cepas de Streptococcus salivarius para seu uso potencial como probióticos na cavidade bucal, ou seja, produção de bacteriocinas contra Streptococcus pyogenes e habilidade de aderência à células KB. Material e método Coletou-se material de língua de 45 estudantes e semeou-se em placas de ágar Mitis Salivarius. As amostras foram testadas para verificar a produção de substâncias semelhantes à bacteriocina (BLIS) contra S. pyogenes, bioquimicamente e através de PCR para identificação de S. salivarius. As melhores cepas foram testadas quanto aderência à células KB. Resumidamente, as cepas de S. salivarius foram cultivadas em caldo, lavadas e suspensas à correspondência de 108 cels/ml. As células KB foram inoculadas em placas, lavadas e incubadas com as bactérias, para adesão. Estas foram lavadas para lise das células KB e liberação das bactérias para determinação de UFC. Resultado O teste de bacteriocina, mostrou que 133 cepas apresentaram atividade inibitória contra Streptococcus pyogenes. As cepas testadas para aderência à células KB, apresentaram diferentes perfis e somente três com alta capacidade de adesão. Conclusão: A seleção de cepas de Streptococcus salivarius com alta atividade inibitória contra Streptococcus pyogenes, bem como aderência a células KB, pode nos levar ao próximo passo, ou seja, o uso das melhores cepas para o estudo de colonização in vivo.

Effects of chrysin on the apoptosis in oral squamous carcinoma KB cell line and the underlying mechanisms / 中南大学学报(医学版)

To investigate the effect of chrysin on apoptosis of oral squamous carcinoma KB cell line and the possible mechanisms, and to provide new ideas for the treatment of oral cancer.
 Methods: Oral cancer KB cells were treated with different concentrations of chrysin (1, 2, 4, 8, 16, and 32 μmol/L) for 24 h. Cell proliferation was detected by MMT assay; apoptosis was detected by flow cytometry; the activity of caspase-3/7 was detected by chemiluminescent assay; mitochondrial membrane potential in KB cells was determined by JC-1 assay; and Western blotting was used to determine the activation of protein kinase B (AKT) and phosphoinositide-3-kinase (PI3K).
 Results: Chrysin inhibited the proliferation of KB cells in a concentration-dependent manner, accompanied by increase in apoptosis of KB cells, activation of caspase-3/7, decrease in mitochondrial membrane potential, and suppression of the phosphorylation of AKT and PI3K.
 Conclusion: The effect of chrysin on KB cell apoptosis may be related to mitochondrial dysfunction and inhibition of PI3K/AKT pathway.

Cytotoxic and apoptotic potential of Myristica fragrans Houtt. (mace) extract on human oral epidermal carcinoma KB cell lines

Several studies have revealed that certain naturally occurring medicinal plants inhibit the growth of various cancers. The present study was conducted to evaluate cytotoxicity and apoptotic induction potential of Myristica fragrans Houtt mace extract. The cytotoxic activity of the Myristica fragrans Houtt mace acetone extract was assayed by MTT assay on human oral epidermal carcinoma KB cell lines. KB cells were incubated with different concentration of mace extract ranging from 25 to 125 µg/mL for 24hrs. The apoptotic induction potential was also studied by the analysis of Bcl-2 protein and gene expression in mace extract incubated KB cell lines using western blotting technique and real-time polymerase chain reaction. The mace extract exhibited cytotoxicity and anticancer effect against KB cell lines and it also suppressed the growth of cancer cells, therefore growth inhibitory effect was noted in extract treated cell lines. The apoptotic potential of mace extract was accompanied by reduced gene expression of Bcl-2 compared to the untreated KB cells. The mace extract shows the cytotoxic activity and induced the apoptosis through the modulation of its target genes Bcl-2 in the KB cell lines, suggesting the potential of mace as a candidate for oral cancer chemoprevention. This can be further investigated in vivo for its anticancer potential.

Effect of β-carotene on Cell Growth Inhibition of KB Human Oral Cancer Cells

β-carotene is present in carrots, pumpkins, and sweet potatoes. It suppresses many types of cancers by regulating cellular proliferation and apoptosis through a variety of mechanisms. However, the effects of β -carotene on oral cancer cells have not been clearly established. The main goal of this study was to investigate the effects of β-carotene on cell growth and apoptosis in oral cancer cells. Our results demonstrate that treatment with β-carotene induced inhibition of cell growth, and that the effect was dependent on β-carotene treatment time and concentration in KB cells. Furthermore, treatment with β-carotene induced nuclear condensation and fragmentation in KB cells. β-carotene promoted proteolytic cleavage of procaspase-3, -7, -8 and -9 with associated increases in the concentration of cleaved caspase-3, -7, -8 and -9. In addition, the level of cleaved PARP was increased by β-carotene treatment in KB cells. These results suggest that β-carotene can suppress cell growth and induce apoptosis in KB human oral cancer cells, and that it may have potential usefulness in anti-cancer drug discovery efforts.

Influence of Tyrosol on Cell Growth Inhibition of KB Human Oral Cancer Cells

Tyrosol, a phenylethanoid and a derivative of phenethyl alcohol, possesses various biological properties, such as anti-oxidative and cardioprotective activity. Olive oil is the principal source of tyrosol in the human diet. However, so far the anti-cancer activity of tyrosol has not yet been well defined. This study therefore undertakes to examine the cytotoxic activity and the mechanism of cell death exhibited by tyrosol in KB human oral cancer cells. Treatment of KB cells with tyrosol induced the cell growth inhibition in a concentration- and a time-dependent manner. Furthermore, the treatment of tyrosol induced nuclear condensation and fragmentation of KB cells. Tyrosol also promoted proteolytic cleavage of procaspase-3, -7, -8 and -9, increasing the amounts of cleaved caspase-3, -7, -8 and -9. In addition, tyrosol increased the levels of cleaved PARP in KB cells. These results suggest that tyrosol induces the suppression of cell growth and cell apoptosis in KB human oral cancer cells, and is therefore a potential candidate for anti-cancer drug discovery.

In silico target fishing for the potential bioactive components contained in Huanglian Jiedu Tang (HLJDD) and elucidating molecular mechanisms for the treatment of sepsis / 中国天然药物

The present study was designed to target fish for potential bioactive components contained in a Huang Lian Jie Du decoction (HLJDD) and identify the underlying mechanisms of action for the treatment of sepsis at the molecular level. he bioactive components database of HLJDD was constructed and the sepsis-associated targets were comprehensively investigated. The 3D structures of the PAFR and TXA2R proteins were established using the homology modelling (HM) method, and the molecular effects for sepsis treatment were analysed by comparing the bioactive components database and the sepsis targets using computational biology methods. The results of the screening were validated with biological testing against the human oral epidermal carcinoma cell line KB in vitro. We found that multiple bioactive compounds contained in the HLJDD interacted with multiple targets. We also predicted the promising compound leads for sepsis treatment, and the first 28 compounds were characterized. Several compounds, such as berberine, berberrubine and epiberberine, dose-dependently inhibited PGE2 production in human KB cells, and the effects were similar in the presence or absence of TPA. This study demonstrates a novel approach to identifying natural chemical compounds as new leads for the treatment of sepsis.

Antimicrobial Effect of Coptidis rhizome Extract against Mutans Streptococci and Periodontopathogens

The purpose of the study was to investigate the antimicrobial activity of the methanol extract of Coptidis rhizome against the type strains of cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, and the periodontopathogens, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extract and the methanol extract fractions of Coptidis rhizome separated by silica gel chromatography were evaluated by determining the minimal bactericidal concentration (MBC) values, using the microdilution method. The cell viability test of the extracts of Coptidis rhizome on the KB cells was also studied by methyl thiazolyl tetrazolium (MTT) assay. Our results showed that the 11th fraction (F11) of the methanol extract had the greatest antimicrobial activity against the tested bacteria, with no associated cytotoxicity on the KB cells, upto a concentration of 50 microg/ml. These results suggest that the silica gel chromatography fraction F11 of the methanol extract of Coptidis rhizome, could be useful in the development of oral hygiene products as an antimicrobial agent for the prevention of dental caries and periodontal diseases.

Effect of smokers'sera on Porphyromonas gingivalis internalizing KB cells and the expression of matrix metalloproteinase-1, -9 and tissue inhibitor of metalloproteinase-1 / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of serum from smoking individuals or non-smoking individuals with periodontitis on Porphyromonas gingivalis (Pg) internalizing KB cells, and the expression of matrix metalloproteinase(MMP)-1, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1) in the culture supernatant of KB cells.</p><p><b>METHODS</b>The venous blood of 20 periodontitis patients' (10 smoking and 10 non-smoking) was extracted under the informed consent and centrifuged for serum. The smoking-individual serum (Y group) and non-smoking-individual (N group) serum were added to the model of Pg internalizing KB cells for 12 hours, plated on brain-heart infusion (BHI) and incubated anaerobically at 37 °C for 5 days. The colony forming units (CFU) of cell-invasive bacteria were estimated by colony counting. MMP-1, MMP-9 and TIMP-1 protein levels in culture supernatant were determined by enzyme-linked immunosorbent assay(ELISA) in the two groups following co-culture of Pg with KB cells for 12 hours.</p><p><b>RESULTS</b>The CFU were (11.2 ± 1.1)×10(4), (12.6 ± 1.2)×10(4), (44.7 ± 1.3)×10(4) CFU/ml when adding 200, 400, 800 µl Y-group serum to the model of Pg co-culture with KB cells and when the serum was extracted from N group, the CFU were (33.6 ± 1.4)×10(4),(38.9 ± 1.1)×10(4), (11.2 ± 1.2)×10(4) CFU/ml respectively. When 200, 400, 800 µl Y group-serum was added to co-culture fluid of Pg internalizing KB cells, the concentrations of MMP-1 secreted from KB cells were (107.2 ± 21.5), (165.9 ± 20.2), (434.4 ± 48.0) µg/L respectively, the concentrations of MMP-9 were (3.99 ± 0.29), (4.21 ± 0.61), (5.62 ± 0.47) µg/L respectively, the concentrations of TIMP-1 were (401.3 ± 12.7), (418.3 ± 28.5), (637.3 ± 37.3) µg/L. When the serum (200, 400, 800 µl) extracted from N group, the concentration of MMP-1 and MMP-9 secreted by KB cell were (77.6 ± 10.8), (84.7 ± 10.2) and (98.2 ± 9.7) µg/L and (3.84 ± 0.52), (4.02 ± 0.68), (4.25 ± 0.37) µg/L, respectively. The concentration of TIMP-1 were (67.3 ± 26.9) , (89.4 ± 22.7) and (78.2 ± 16.5) µg/L secreted by KB cells in the course of Pg internalized KB cell. With the increasing of Y group-serum, the more MMP-1, MMP-9 and TIMP-1 were secreted by KB cells(P < 0.05). When 800 µl Y group-serum was added compared with N group-serum to the Pg co-culture with KB model, the more MMP-1, MMP-9 and TIMP-1 were secreted by KB cells(P < 0.05), when 400 µl Y group-serum was added compared with N group-serum to the Pg co-culture with KB model, the more MMP-1 and TIMP-1 were secreted by KB cells (P < 0.05).</p><p><b>CONCLUSIONS</b>The smoking-serum might enhance Pg internalizing KB cells and enhance the expression of MMP-1, MMP-9 and TIMP-1 secreted from KB cells. The local microenvironment of smoking individual may contribute to the recurrence and progression of chronic periodontitis.</p>

Effects of metformin on human oral cancer KB cell proliferation and apoptosis in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of metformin on the proliferation and apoptosis of human oral cancer cell line KB in vitro.</p><p><b>METHODS</b>Human oral cancer cell line KB was exposed to different doses of metformin (0, 1.25, 2.5, 5, 10, and 20 mmol/L), and the changes in cell viability were detected using MTT assay. Colony formation of the cells was observed following an 8-day metformin exposure. The changes in mitochondrial membrane potential were measured by JC-1 assay, and PI staining was used to observe the cell apoptosis. Western blotting was employed to detect the changes in the protein expressions of GRP78 and activated caspase-3.</p><p><b>RESULTS</b>Metformin exposure caused time- and dose-dependent suppression of KB cell proliferation, and exposure to 5 mmol/L metformin for 24, 48 and 72 h resulted in cell survival rates of 68.0%, 36.9%, and 14.5%, respectively. Metformin significantly inhibited KB cell colony formation. Exposure of the cells to increased concentrations of metformin gradually increased the apoptotic rate and decreased mitochondrial membrane potential. Metformin caused an initial up-regulation followed by a down-regulation of GRP78 expression in KB cells and increased the expression of activated caspase-3.</p><p><b>CONCLUSION</b>Metformin can inhibit the proliferation and induce apoptosis of KB cells, the mechanism of which may involve the activation of the mitochondrial apoptotic pathway and endoplasmic reticulum stress.</p>

Small interfering RNA-mediated COX-2 gene silencing enhances chemosensitivity of KB/VCR cells by suppressing MDR-1 gene expression and P-glycoprotein activity / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA (siRNA)-mediated COX-2 gene silencing in enhancing the chemosensitivity of KB/VCR cell lines.</p><p><b>METHODS</b>KB/VCR cells were trasnfected with COX-2 siRNA were examined for expressions of COX-2 and MDR-1 mRNAs with RT-PCR and for Rho-123 accumulation using flow cytometry. MTT assay was used to analyze the proliferation of the transfected KB/VCR cells.</p><p><b>RESULTS</b>Compared with the negative and blank control groups, COX-2 siRNA transfection resulted in significant growth inhibition of KB/VCR cells exposed to vincristine (P<0.01), down-regulated the expressions of COX-2 and MDR-1 mRNAs, and obviously increased Rho-123 accumulation in KB/VCR cells.</p><p><b>CONCLUSION</b>COX-2 gene silencing can enhance the chemosensitivity of KB/VCR cells to vincristine, the mechanism of which may involve down-regulated MDR-1 gene expression and inhibition of P-glycoprotein activity.</p>

Antimicrobial Activity of Mulberry Leaf against Mutans Streptococci and Periodontopathogens

This study investigated the antimicrobial activity of methanol extract of mulberry leaf against 16 strains of mutans streptococci and four species of periodontopathogens: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of the crude extracts or silica gel chromatography fractions of methanol-extracted mulberry leaf were evaluated by determining minimal inhibitory concentrations using an established microdilution method. The cytotoxicity of the extracts of mulberry leaf on KB cells was tested by the methyl thiazolyl tetrazolium assay. Chromatography fraction 12 displayed the most potent antimicrobial activity against all 16 strains of mutans streptococci, P. gingivalis, and P. intermedia. No KB cell cytotoxicity was evident up to 128 microg/ml of fraction 12. The methanol extract had no antimicrobial activity against F. nucleatum and A. actinomycetemcomitans. These results suggest chromatography fraction 12 methanol extract of mulberry leaf could be useful in the development of oral hygiene products, such as dentifrice and oral hygiene solution, for the prevention of dental caries.

Celecoxib enhances chemosensitivity of oral cancer cells by blocking cell cycle progression in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of celecoxib in enhancing the chemosensitivity of oral cancer cells and the correlation of this effect with cell cycle arrest.</p><p><b>METHODS</b>KB/VCR cell line was treated with celecoxib (10, 20, 40, and 80 µmol/L) and/or VCR (0.375, 0.75, 1.5, and 3 µmol/L), and the growth inhibition rates of KB/VCR cells were assessed with MTT assay. Flow cytometry was employed to analyze the distribution of cell cycle. Western blotting was performed to detect the expression of P-glycoprotein (P-gp) and the cell cycle related proteins Cyclin D1 and p21(WAF1/CIP1).</p><p><b>RESULTS</b>Low concentrations of celecoxib (<20 µmol/L) produced no obvious effect on the proliferation of the cells. But at 10 µmol/L, celecoxib significantly enhanced the toxicity of VCR in a time-dependent manner, and the combined treatments for 24, 48, and 72 h caused growth inhibition rates of (37.53∓2.05)%, (46.67∓3.17)% and (54.02∓1.53)%, respectively, significantly higher than those following treatments with celecoxib or VCR alone (P<0.01). Compared with the cells treated with VCR alone , the cells with combined treatments showed a significantly increased cell percentage in G0/G1 phase [(56.08∓0.46)%] with decrease percentages in S phase [(22.83∓0.20)%] and G2/M phase [(21.09%∓0.66)%]. The combined treatment also significantly down-regulated cyclin D1, up-regulated p21(WAF1/CIP1), and reduced P-gp expressions in the cells.</p><p><b>CONCLUSIONS</b>Celecoxib enhances the chemosensitivity of KB/VCR cells by down-regulating P-gp expression, which is partially mediated by modification of cyclin D1 and p21(WAF1/CIP1) to result in cell cycle arrest.</p>

ABCG2-overexpressing S1-M1-80 cell xenografts in nude mice keep original biochemistry and cell biological properties / 癌症

S1-M1-80 cells, derived from human colon carcinoma S1 cells, are mitoxantrone-selected ABCG2-overexpressing cells and are widely used in in vitro studies of multidrug resistance(MDR). In this study, S1-M1-80 cell xenografts were established to investigate whether the MDR phenotype and cell biological properties were maintained in vivo. Our results showed that the proliferation, cell cycle, and ABCG2 expression level in S1-M1-80 cells were similar to those in cells isolated from S1-M1-80 cell xenografts (named xS1-M1-80 cells). Consistently, xS1-M1-80 cells exhibited high levels of resistance to ABCG2 substrates such as mitoxantrone and topotecan, but remained sensitive to the non-ABCG2 substrate cisplatin. Furthermore, the specific ABCG2 inhibitor Ko143 potently sensitized xS1-M1-80 cells to mitoxantrone and topotecan. These results suggest that S1-M1-80 cell xenografts in nude mice retain their original cytological characteristics at 9 weeks. Thus, this model could serve as a good system for further investigation of ABCG2-mediated MDR.

Effect of PG0839 gene of Porphyromonas gingivalis on inflammatory cytokine in human oral epidermoid carcinoma KB cell / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of PG0839 gene form Porphyromonas gingivalis (Pg) on inflammatory cytokine expression in human oral epidermoid carcinoma KB cell.</p><p><b>METHODS</b>A mutant in the PG0839 gene of Pg was created by insertional inactivation. Group 1 was chanllenged with PgW83 strain, group 2 with PG0839-defective mutant, and the control group with Dulbecco's modified Eagle's medium only. KB cells were co-cultured with presence of bacteria for 24 h. At the time point of 0.5, 2, 6, 12 and 24 h, cells were stored in Trizol. The mRNA expression of interleukin-1β (IL-1β) and Toll like recepector-4 (TLR-4) was examined by reverse transcription polymerase chain reaction.</p><p><b>RESULTS</b>At 2 h and 6 h, IL-1β mRNA expression was lower in group 2 than in group 1 (2 h: 0.31 ± 0.11 versus 0.95 ± 0.48, P < 0.05; 6 h: 0.57 ± 0.20 versus 1.29 ± 0.55, P < 0.05). At 0.5 h and 6 h, TLR-4 mRNA expression was lower in group 2 than in group 1 (0.5 h: 0.20 ± 0.09 versus 0.58 ± 0.09, P < 0.05; 6 h: 0.34 ± 0.04 versus 0.71 ± 0.18, P < 0.05).</p><p><b>CONCLUSIONS</b>PG0839 gene may play an important role in Pg-induced inflammatory effects of KB cell.</p>

Inhibition of Lymphatic Endothelial Growth Factor Receptor in a Murine Model of Oral Squamous Cell Carcinoma

Effect of Weissella cibaria on Fusobacterium nucleatum-induced Interleukin-6 and Interleukin-8 Production in KB Cells

Oral microorganisms, including pathogens together with commensals, interact with oral epithelial cells, which can lead to the activation and expression of a variety of inflammatory mediators in epithelial cells. Fusobacterium nucleatum is a filamentous human pathogen that is strongly associated with periodontal diseases. Our previous data suggest that Weissella cibaria, an oral commensal, inhibits the proliferation of periodontopathic bacteria including F. nucleatum. The aim of this study was to examine the effects of W. cibaria on the inflammatory mediators, interleukin (IL)-6 and IL-8, in KB cells stimulated by F. nucleatum. In a reverse transcription-polymerase chain reaction and an enzyme-linked immunosorbent assay, live F. nucleatum alone induced high levels of gene expression and protein release of IL-6 and IL-8, whereas W. cibaria alone did not induce IL-6 and IL-8 responses in KB cells. W. cibaria dose-dependently inhibited the increases of the IL-6 and IL-8 gene expression as well as IL-6 protein level in KB cells which was induced by F. nucleatum. Bacterial viability and its coaggregation with F. nucleatum are not essential in the inhibitory effect of W. cibaria. Visible effects of W. cibaria on the attachment and invasion of KB cells by F. nucleatum were observed. In conclusion, W. cibaria may exert immunomodulatory effects on the IL-6 and IL-8 responses to F. nucleatum-activated KB cells.

Anti-MDR tumor mechanism of CIP-36, a podophyllotoxin derivative / 药学学报

This study is to investigate the antitumor activity of CIP-36 on multidrug resistant human oral squamous carcinoma cell line (KBV200 cells) in vitro and the possible anticancer mechanisms. MTT assay, Hoechst fluorescein stain, RT-PCR and immunohistochemistry were carried out on KBV200 and KB cells. The growth of many tumor cells was obviously inhibited by CIP-36, especially the multidrug resistant cells KBV200. Obvious apoptosis could be observed in the Hoechst 33342 staining experiments. The results of RT-PCR showed that the levels of p53, p21, caspase-3 and bax mRNA increased, and meanwhile the expression of mdr-1 and bcl-2 mRNA decreased in a dose-dependent manner. The data were significantly different from that of vehicle. The expression of P-gp significantly decreased with the increasing dosage of CIP-36 examined by immunohistochemistry. It can be concluded that CIP-36 could change resistance-related genes and proteins to overcome multidrug resistance in the KBV200 cell line.

Antimicrobial Effects of Ursolic Acid against Mutans Streptococci Isolated from Koreans

Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 microg/ml and 4 microg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175T and S. sobrinus ATCC 33478T at > 2 x MIC (4 microg/ml) and 4 x MIC (8 microg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.

Cytotoxicity and genotoxicity of endodontic irrigants on human cells / Citotoxicidade e genotoxicidade de irrigantes endodônticos em células humanas

OBJECTIVE: Endodontic irrigants solutions with antibacterial activity have been used in treatment of teeth with infected root canals; however, these solutions can irritate periapical tissues. The aim of this study was to evaluate the cytotoxity and genotoxicity of different endodontic irrigants solutions – sodium hypochlorite (1% and 2%), calcium hydroxide (0.2%), and HCT20 in human KB cells. MATERIAL AND METHOD: Cells were incubated with solutions for 2 and 24 hours. The cell viability was assessed after the trypan blue exclusion and the frequency of cell death mechanism (apoptotic or necrotic) was determined by acridine orange/ethidium bromide fluorescent dyeing test. The genotoxicity effects were assessed by the micronucleus assays. RESULTS AND DISCUSSION: The results showed that Ca(OH)2 alone or in combination with tergentol (HCT20), and NaOCl induced cytotoxicity in KB causing death cells by apoptosis. The micronuclei test showed that KB treated with NaOCl (1%) present an increase in the frequency of micronucleus compared to the control group.

OBJETIVO: Soluções irrigadoras com atividade antibacteriana têm sido usadas no tratamento de dentes com canais radiculares infectados; entretanto, essas soluções podem irritar os tecidos periapicais. O objetivo deste estudo foi avaliar a citotoxicidade e genotoxicidade de diferentes soluções irrigadoras – hipoclorito de sódio (1% e 2%), hidróxidode cálcio (0,2 %) e HCT em células humanas KB. MATERIAL E MÉTODO: As células foram incubadas em soluções por 2 e 24 horas. A viabilidade celular foi determinada após exclusão do tripan blue e a frequência de mecanismo de morte celular (apoptótica ou necrótica) foi determinada pelo teste acridine Orange/ethidium bromide fluorescen dyeing. Os efeitos de genotoxicidade foram determinados pelo ensaio de micronúcleos. RESULTADOS E DISCUSSÃO: Os resultados demonstraram que o Ca(OH2), isoladamente ou em combinação com Tergentol™ (HCT20) e NaOCl, induziram citotoxicidade em KB, causando morte celular por apoptose. O teste de micronúcleos demonstrou que KB tratado codm NaOCl (1%) apresentou aumento na frequência de microdnúcleos quando comparadocom o grupo controle.

Characteristics of boningmycin induced cellular senescence of human tumor cells / 药学学报

Cellular senescence is one of the important steps against tumor. This study was to observe the characteristics of boningmycin induced senescence of human tumor cells. MIT method and clone formation assay were used to detect the growth-inhibitory effect. Cellular senescence was detected with senescence-associated beta-galactosidase staining. Cell cycle distribution and accumulation of intracellular reactive oxygen species (ROS) were analyzed with flow cytometry. Protein expression was detected by Western blotting. The results showed that the growth-inhibitory effect of boningmycin was obviously stronger on human oral epithelial carcinoma KB cells than that on non-small cell lung cancer A549 cells. Comparison to the similar action of doxorubicin, that boningmycin induced the features of cellular senescence in both cell lines, its due to the arrest at G2/M phase and an increase of ROS level. The molecular senescence marker P21 increased significantly after boningmycin treatment at a dosage of 0.1 micromol x L(-1), whereas a higher concentration of it induced apoptosis. The results indicated that cellular senescence induced by boningmycin was one of its mechanisms in tumor suppression.