Combined QSAR-based virtual screening and fluorescence binding assay to identify natural product mediators of Interferon Regulatory Factor 7 (IRF-7) in pulmonary infection

Interferon regulatory factor-7 (IRF-7) is involved in pulmonary infection and pneumonia. Here, a synthetic strategy that combined quantitative structure-activity relationship (QSAR)-based virtual screening and in vitro binding assay was described to identify new and potent mediator ligands of IRF-7 from natural products. In the procedure, a QSAR scoring function was developed and validated using Gaussian process (GP) regression and a structure-based set of protein-ligand affinity data. By integrating hotspot pocket prediction, pharmacokinetics profile analysis and molecular docking calculations, the scoring function was successfully applied to virtual screening against a large library of structurally diverse, drug-like natural products. With the method we were able to identify a number of potential hits, from which several compounds were found to have moderate or high affinity to IRF-7 using fluorescence binding assays, with dissociation constants K_d at micromolar level. We have also examined the structural basis and noncovalent interactions of computationally modelled IRF-7 complex with its potent ligands. It is revealed that hydrophobic forces and van der Waals contacts play a central role in stabilization of the complex architecture, while few hydrogen bonds confer additional specificity for the protein-ligand recognition.

Efficacy and safety of liraglutide versus sitagliptin, both in combination with metformin, in Chinese patients with type 2 diabetes: a 26-week, open-label, randomized, active comparator clinical trial

AIMS

To compare the efficacy and safety of liraglutide versus sitagliptin as add-on to metformin after 26 weeks of treatment in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

This 26-week open-label, active comparator trial (NCT02008682) randomized patients (aged 18-80 years) with T2DM inadequately controlled with metformin [glycated haemoglobin (HbA1c) 7.0-10.0% (53-86 mmol/mol)] 1 : 1 to once-daily subcutaneously administered liraglutide 1.8 mg (n = 184) or once-daily oral sitagliptin 100 mg (n = 184), both as add-on to metformin. The primary endpoint was change in HbA1c from baseline to week 26.

RESULTS

Liraglutide was superior to sitagliptin in reducing HbA1c from baseline [8.1% (65 mmol/mol)] to 26 weeks, as evidenced by estimated mean HbA1c change of -1.65% (-18.07 mmol/mol) versus -0.98% (-10.72 mmol/mol), respectively [estimated treatment difference for liraglutide vs sitagliptin of -0.67% (95% CI -0.86, -0.48) or -7.35 mmol/mol (95% CI -9.43; -5.26); p < 0.0001]. More patients receiving liraglutide (76.5%) than sitagliptin (52.6%) achieved the HbA1c target of <7.0% (53 mmol/mol) at week 26 [odds ratio 3.65 (95% CI 2.18, 6.12); p < 0.0001]. Reductions in fasting plasma glucose, 7-point self-measured plasma glucose and body weight were greater with liraglutide than with sitagliptin (p < 0.0001 for all). More patients experienced nausea (14.8% vs 0.5%), diarrhoea (8.2% vs 2.2%) and decreased appetite (10.9% vs 0.5%) with liraglutide than sitagliptin. Two hypoglycaemic episodes were confirmed for liraglutide and one for sitagliptin; none were severe or nocturnal.

CONCLUSIONS

Liraglutide provided better glycaemic control and greater body weight reduction than sitagliptin when administered as add-on to metformin. More patients had nausea, diarrhoea and decreased appetite with liraglutide versus sitagliptin.

The four and a half LIM domains 2 (FHL2) regulates ovarian granulosa cell tumor progression via controlling AKT1 transcription

The four and a half LIM domains 2 (FHL2) has been shown to play important roles in the regulation of cell proliferation, survival, adhesion, motility and signal transduction in a cell type and tissue-dependent manner. However, the function of FHL2 in ovarian physiology and pathology is unclear. The aim of this study was to determine the role and functional mechanism of FHL2 in the progression of ovarian granulosa cell tumors (GCTs). Immunohistochemical analysis indicated that FHL2 was overexpressed in GCT tissues. Cellular localization of FHL2 in GCT cells was cell cycle dependent. Knockdown of FHL2 suppressed GCT cell growth, reduced cell viability and inhibited cell migration. Consistently, ectopic expression of FHL2 in GCT cells with very low endogenous FHL2 promoted cell growth, improved cell viability and enhance cell migration. Importantly, overexpression of FHL2 promoted GCT progression in vivo. Mechanistic studies indicated that FHL2 regulates AKT1 gene expression in vitro and in vivo. Knockdown of FHL2 or AKT1 in GCT cell lines induced very similar phenotypes. Ectopic expression of constitutively active AKT1 rescued FHL2 knockdown-induced arrest of GCT cell growth and reduction of GCT cell viability, suggesting that FHL2 regulates GCT cell growth and viability through controlling AKT1 expression. Finally, co-immunoprecipitation and chromatin immunoprecipitation analyses indicated that FHL2 functions as a co-activator of NFκB and AP-1 to regulate AKT1 gene transcription. In conclusion, results from the present study indicate that FHL2 exerts its oncogenic action in GCT cells via controlling AKT1 gene expression. FHL2 is a promising target for the development of novel drugs against ovarian granulosa cell tumor.

A meta-analysis of erlotinib versus docetaxel for advanced nonsmall-cell lung cancer with poor prognosis

BACKGROUND

The extent of the benefit of erlotinib in the treatment of advanced nonsmall-cell lung cancer (NSCLC) is still controversial when compared with docetaxel. This meta-analysis was performed to compare the efficacy of erlotinib with docetaxel for different patients with advanced NSCLC.

MATERIALS AND METHODS

We searched Cochrane Library, PubMed, CNKI, and identified 23 randomized controlled clinical trials from 2008 to 2015. According to our further full-text screening, 6 clinical trials were included in the final meta-analysis.

RESULTS

Six papers were included in this study. The progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and toxicity were included in our outcomes. The pooled hazard ratio (HR) of PFS was 1.57 (95% confidential index [CI] = 1.47-1.69). The pooled HR of OS was 1.66 (95% CI = 1.43-1.92). The pooled risk ratio of ORR was 0.56 (95% CI = 0.35-0.91). The toxicity analysis showed odds ratio = 1.79 (95% CI = 1.20-2.69).

CONCLUSIONS

In terms of PFS, OS, and toxicity the effect of erlotinib in the treatment of advanced NSCLC patients is superior to docetaxel.

YAP induces high-grade serous carcinoma in fallopian tube secretory epithelial cells

Accumulating evidence indicates that ovarian high-grade serous carcinoma (HGSC) originates from fallopian tube secretory epithelial cells (FTSECs). However, the molecular mechanisms underlying the initiation and progression of HGSC derived from FTSECs remains unclear. In this study, we found that the Hippo/Yes-associated protein (YAP) signaling pathway has a critical role in the initiation and progression of fallopian tube and ovarian HGSC. Importantly, YAP was overexpressed in inflammatory and cancerous fallopian tube tissues. Further, overexpression of wild-type YAP, or constitutively active YAP in immortalized FTSECs, induced cell proliferation, migration, colony formation and tumorigenesis. Moreover, the Hippo/YAP and the fibroblast growth factor (FGF) signaling pathways formed an autocrine/paracrine-positive feedback loop to drive the progression of the FTSEC-derived HGSC. Evidence in this study strongly suggests that combined therapy with inhibitors of YAP (such as verteporfin) and FGF receptors (such as BGJ398) can provide a novel therapeutic strategy to treat fallopian tube and ovarian HGSC.

Evaluation of cytotoxicity of some common ophthalmic drugs

The article "Evaluation of cytotoxicity of some common ophthalmic drugs" by M. Li, X.-M. Chen, J.-J. Liu, D.-M. Wang, L. Gan, X. Lv, Y. Qiao, published in Eur Rev Med Pharmacol Sci 2015; 19 (11): 1945-1950 has been withdrawn.

EGFR signaling upregulates surface expression of the GluN2B-containing NMDA receptor and contributes to long-term potentiation in the hippocampus

N-methyl-d-aspartate receptors (NMDARs) have been known to be regulated by various receptor tyrosine kinases. Activation of epidermal growth factor receptor (EGFR) specifically increases NMDAR-mediated currents and enhances long-term potentiation (LTP) in the hippocampus. However, the mechanism through which EGFR regulates NMDARs remains to be elucidated. In this study we found that EGFR was highly expressed in the hippocampus and mainly localized in the non-synaptic region including the soma and neurites of cultured hippocampal neurons. EGFR activation led to an increase in ifenprodil-sensitive NMDAR currents. Consistent with this, we also observed that surface expression of GluN2B-containing NMDAR was upregulated. Our biochemical data from hippocampal slices and hippocampal cultured neurons demonstrated that EGF treatment in vitro significantly increased phosphorylation of the GluN2B subunit at Y1472 with a coincidental activation of Src family kinases (SFKs). EGFR blockade with a specific antagonist BIBX-1382 attenuated an increase of GluN2B in the postsynaptic density during high-frequency stimulation (HFS)-induced LTP. Moreover, BIBX blockade significantly impaired HFS-induced LTP. In conclusion, our findings suggest that EGFR signaling upregulates NMDARs through modification of the GluN2B subunit, and is required for HFS-induced LTP in the hippocampus.

Hypoxia upregulates Rab11-family interacting protein 4 through HIF-1α to promote the metastasis of hepatocellular carcinoma

Hypoxic microenvironment is a powerful driving force for the invasion and metastasis of hepatocellular carcinoma (HCC). Hypoxia-inducible factor 1α (HIF-1α), as a crucial regulator of transcriptional responses to hypoxia, induces the expression of multiple target genes involved in different steps of HCC metastatic process. It is critical to find target genes associated with metastasis under hypoxia for shedding new light on molecular mechanism of HCC metastasis. In this study, we uncovered that hypoxia could induce the upregulation of Rab11-family interacting protein 4 (Rab11-FIP4) and activation of Rab11-FIP4 promoter by HIF-1α. The overexpression of Rab11-FIP4 significantly enhanced the mobility and invasiveness of HCC cells in vitro, also contributed to distant lung metastasis in vivo, whereas silencing of Rab11-FIP4 decreased the ability of migration and invasion in HCC cells in vitro and suppressed lung metastasis in vivo. Rab11-FIP4 facilitated HCC metastasis through the phosphorylation of PRAS40, which was regulated by mTOR. Furthermore, the expression level of Rab11-FIP4 was significantly increased in HCC tissues and high expression of Rab11-FIP4 was closely correlated with vascular invasion and poor prognosis in HCC patients. A markedly positive correlation between the expression of Rab11-FIP4 and HIF-1α was observed in HCC tissues and combination of Rab11-FIP4 and HIF-1α was a more valuable predictor of poor prognosis for HCC patients. In conclusion, Rab11-FIP4 is a target gene of HIF-1α and has a pro-metastatic role in HCC, suggesting that Rab11-FIP4 may be a promising candidate target for HCC treatment.

Comparison of the effects on glycaemic control and β-cell function in newly diagnosed type 2 diabetes patients of treatment with exenatide, insulin or pioglitazone: a multicentre randomized parallel-group trial (the CONFIDENCE study)

OBJECTIVE

Progressive β-cell dysfunction hinders the maintenance of glycaemic control in type 2 diabetes, but comparative data on β-cell-protective therapies are lacking in the early stage of type 2 diabetes. Here we evaluated the comparative glycaemic efficacy and impact on β-cell function of three antihyperglycaemic agents that have a β-cell-protective effect, exenatide, insulin and pioglitazone, in newly diagnosed patients with type 2 diabetes.

DESIGN AND METHODS

In this 48-week, multicentre, parallel-group study, 416 patients newly diagnosed with type 2 diabetes were randomly assigned 1 : 1 : 1 to receive exenatide, insulin or pioglitazone. The primary end-point was the change in glycosylated haemoglobin (HbA1c) from baseline. Secondary end-points included effects on weight, blood pressure, lipid profiles and β-cell function assessed by homeostasis model assessment, fasting proinsulin:insulin (PI/I), disposition index (DI) and acute insulin response (AIR).

RESULTS

At week 48, mean [95% confidence interval (CI)] HbA1c changes from baseline were -1.8% (-1.55% to -2.05%) with exenatide, -1.7% (-1.52% to -1.96%) with insulin and -1.5% (-1.23% to -1.71%) with pioglitazone. Treatment differences were -0.20% (95% CI -0.46% to 0.06%) for exenatide versus insulin (P = 0.185), and -0.37% (95% CI -0.63% to -0.12%) for exenatide versus pioglitazone (P = 0.002). Significant improvements from baseline in AIR, PI/I and DI were observed with all treatments, with the greatest improvements in DI, as well as weight, blood pressure and lipid profile, observed with exenatide.

CONCLUSIONS

All three agents showed efficacy regarding glycaemic control and metabolic benefits; however, exenatide showed the greatest efficacy. β-cell function improved in all treatment groups; hence, early initiation of β-cell-protective therapy may halt the decline in β-cell function in type 2 diabetes.

Evaluation of cytotoxicity of some common ophthalmic drugs

OBJECTIVE

The study was aimed at evaluating the in vitro cytotoxicity of some commonly used drugs in ophthalmology. Hydrocortisone sodium succinate, Dexamethasone sodium phosphate, 5-Fluorouracil, Tobramycin and Pilocarpine nitrate are frequently used in various indications involving eye care, and the aim was to test the safety of these in cell culture.

MATERIALS AND METHODS

The in vitro cytotoxicity was carried out on the NIH 3T3 cell line by the Sulforhodamine B (SRB) assay.

RESULTS

With the exception of 5-Fluorouracil, none of the other drugs demonstrated appreciable cytotoxicity up to high concentrations of 200 µg/ml at 48 hours of drug exposure.

CONCLUSIONS

Hydrocortisone sodium succinate, Dexamethasone sodium phosphate, Tobramycin and Pilocarpine nitrate were confirmed to be non-cytotoxic while 5-Fluorouracil was highly cytotoxic especially at 48 hours at very low concentrations.

The association between HLA-DQB1 polymorphism and antituberculosis drug-induced liver injury: a Case-Control Study

WHAT IS KNOWN AND OBJECTIVE

Research on genetic factors associated with antitubercular drug-induced liver injuries (ATLI) has been reported. However, most of the research has focused on genetic polymorphisms of genes encoding metabolic enzymes, including NAT2, GST and CYP450. It is probable that the immune system also contributes to the onset of drug adverse effects. A few small studies have explored the possible association of HLA genes with drug-induced liver injuries (DILI), but more supportive evidence from larger studies or prospective cohort designs is needed. We aim to explore the possible association of HLA-DQB1 gene polymorphisms with ATLI in a case-control study.

METHODS

A case-control study design was used. ATLI was recorded in a prospectively followed-up cohort of patients receiving antituberculosis treatment. Identified cases were matched with control tuberculosis patients within the same cohort but with no adverse effects in 1 : 1 ratio. We used the sequence-based typing method to determine the HLA-DQB1 genotypes. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression.

RESULTS AND DISCUSSION

Eighty-nine cases were included in this case-control study. HLA-DQB1 typing was successful for 177 subjects. No association between frequency of HLA-DQB1 genotypes and ATLI was statistically significant in univariate analyses. Multivariate analysis using the conditional logistic regression model revealed that the individuals with two DQB1*05 alleles were at higher risk of ATLI than control subjects. The OR was 5.28 adjusted for use of liver protective drugs and weight (10/88 VS 2/88, 95% CI: 1.134-24.615, P = 0.034). Analysis according to the liver injury type showed that both mixed liver injury patients and cholestatic/mixed liver injury patients had higher proportions of DQB1*05 : 02 alleles (P values were 0.028 and 0.005, respectively).

WHAT IS NEW AND CONCLUSION

This study suggests that ATLI was more likely in subjects of HLA-DQB1*05/*05 genotype. Further studies are needed to verify this association.

Decreased levels of circulating sex hormones as a biomarker of lung cancer in male patients with solitary pulmonary nodules

BACKGROUND

An early differentiation of malignant from benign solitary pulmonary nodules (SPNs) is essential for management and prognosis of lung cancer.

OBJECTIVES

Here we investigated whether measurement of circulating sex hormones could be useful for an early detection of malignancy among patients with SPNs.

METHODS

We recruited 47 patients with malignant SPNs 45 patients with benign SPNs, and 32 healthy persons. Testosterone, estradiol, and progesterone were measured. Carcinoembryonic antigen (CEA) as well as TNF-α, IL-1 and IL-6 were also measured.

RESULTS

We found that sex hormones were decreased significantly in patients with malignant SPNs, as compared to patients with benign SPNs and healthy controls (P<0.05). Sex hormones levels showed a trend to decline in patients with benign SPNs as compared to normal controls, but the difference was not statistically significant (P>0.05). CEA levels were only abnormally elevated in eight patients with lung adenocarcinoma. The inflammatory cytokines were remarkably higher in both patients than in normal controls. However, there was no statistical difference in these cytokines among patients.

CONCLUSIONS

The reduced sex hormones levels seemed to be uniquely associated with lung cancer. Therefore, measurement of sex hormones may have clinical potential in the diagnosis of malignancy in patients with SPNs.

Dual-source CT versus single-source 64-section CT angiography for coronary artery disease: A meta-analysis

AIM

To perform a meta-analysis to compare the diagnostic performance of single-source 64-section computed tomography (CT) versus dual-source CT angiography for diagnosis of coronary artery disease (CAD).

MATERIALS AND METHODS

The Cochrane Library, MEDLINE, and EMBASE were searched for relevant original papers. Inclusion criteria were (1) significant CAD defined as ≥50% reduction in luminal diameter by invasive coronary angiography as reference standard; (2) single-source 64-section CT or dual-source CT was used; (3) results were reported in absolute numbers of true-positive, false-positive, true-negative, and false-negative results or sufficiently detailed data for deriving these numbers were presented. A random-effects model was used for the meta-analysis.

RESULTS

Fifty-one papers including 3966 patients who underwent single-source 64-section CT and 2047 patients who underwent dual-source CT at a per-patient level were pooled. The diagnostic values of single-source 64-section CT versus dual-source CT were 97% versus 97% for sensitivity (p = 0.386), 78% versus 86% for specificity (p < 0.001), 90% versus 85% for positive predictive value (PPV; p < 0.001), 93% versus 97% for negative predictive value (NPV; p = 0.001), 6.8 versus 6.5 for positive likelihood ratio (p = 0.018), 0.04 versus 0.04 for negative likelihood ratio (p = 0.625), and 191.59 versus 207.37 for diagnostic odds ratio (p = 0.043), respectively.

CONCLUSION

Dual-source CT and single-source 64-section CT have similar negative likelihood ratios and, therefore, there was no significant difference in their utility to rule out CAD in intermediate-risk patients. However, compared to single-source 64-section CT, dual-source CT has significantly higher specificity, so that CT-based decisions for subsequent coronary catheter angiography are more accurate.

Serological and virological surveillance of avian influenza A virus H9N2 subtype in humans and poultry in Shanghai, China, between 2008 and 2010

We report the serological evidence of low-pathogenic avian influenza (LPAI) H9N2 infection in an occupational poultry-exposed population and a general population. A serological survey of an occupational poultry-exposed population and a general population was conducted using a haemagglutinin-inhibiting (HI) assay in Shanghai, China, from January 2008 to December 2010. Evidence of higher anti-H9 antibodies was found in serum samples collected from poultry workers. During this period, 239 H9N2 avian influenza viruses (AIVs) were isolated from 9297 tracheal and cloacal paired specimens collected from the poultry in live poultry markets. In addition, a total of 733 influenza viruses were isolated from 1569 nasal and throat swabs collected from patients with influenza-like symptoms in a sentinel hospital, which include H3N2, H1N1, pandemic H1N1 and B, but no H9N2 virus was detected. These findings highlight the need for long-term surveillance of avian influenza viruses in occupational poultry-exposed workers.

Downregulation of FAP suppresses cell proliferation and metastasis through PTEN/PI3K/AKT and Ras-ERK signaling in oral squamous cell carcinoma

It is largely recognized that fibroblast activation protein (FAP) is expressed in cancer-associated fibroblasts (CAFs) of many human carcinomas. Furthermore, FAP was recently also reported to be expressed in carcinoma cells of the breast, stomach, pancreatic ductal adenocarcinoma, colorectum, and uterine cervix. The carcinoma cell expression pattern of FAP has been described in several types of cancers, but the role of FAP in oral squamous cell carcinoma (OSCC) is unknown. The role of endogenous FAP in epithelium-derived tumors and molecular mechanisms has also not been reported. In this study, FAP was found to be expressed in carcinoma cells of OSCC and was upregulated in OSCC tissue samples compared with benign tissue samples using immunohistochemistry. In addition, its expression level was closely correlated with overall survival of patients with OSCC. Silencing FAP inhibited the growth and metastasis of OSCC cells in vitro and in vivo. Mechanistically, knockdown of FAP inactivated PTEN/PI3K/AKT and Ras-ERK and its downstream signaling regulating proliferation, migration, and invasion in OSCC cells, as the inhibitory effects of FAP on the proliferation and metastasis could be rescued by PTEN silencing. Our study suggests that FAP acts as an oncogene and may be a potential therapeutic target for patients with OSCC.

Screening differential expression of serum proteins in AFP-negative HBV-related hepatocellular carcinoma using iTRAQ -MALDI-MS/MS

Hepatocellular carcinoma(HCC) is serious condition associated with a high morbidity and mortality. Therefore is an urgent need to develop novel noninvasive techniques for early diagnosis, particularly for patients with AFP-negative [AFP(-)] HCC. In this study, iTRAQ-MALDI-MS/MS was used to identify differentially expressed proteins in AFP(-) HBV-related HCC compared with non-cancerous hepatitis B virus (HBV) and healthy controls subjects.Serum was obtained from 18 patients with AFP(-) HBV-related HCC, 18 matched patients with HBV without HCC and 18 healthy control subjects. High abundance proteins were removed from serum and the differentially expressed proteins from the three groups were screened out using iTRAQ-MALDI-MS/MS. The Gene Ontology (GO) function and the interaction networks of differentially expressed proteins were then analyzed. A total of 24 expressed differential proteins associated with AFP(-) HBV-related HCC were screened out, 15 proteins were up-regulated and 9 down-regulated. The most common molecular function of the 24 differentially expressed proteins was enzyme inhibition. Interaction network of the 24 differentially expressed proteins showed that 14 proteins (C5, KNG1, FN1, LRG1, HRG, SERPINC1, CRP, APOB, SAA1, APCS, C4BPA, CFI, CFB and GSN) were central to the functional network. The expression levels of the GSN protein were down-regulated in AFP(-) HBV-related HCC subjects compared with healthy controls and the HBV group (p<0.01), consistent with the iTRAQ results.The 14 proteins from the serum of AFP(-) HBV-related HCC appeared at the fulcrum of the functional network and were differentially expressed compare to HBV and healthy controls suggesting a possible association with HCC progression.

The G-protein-coupled estrogen receptor agonist G-1 suppresses proliferation of ovarian cancer cells by blocking tubulin polymerization

The G-protein-coupled estrogen receptor 1 (GPER) has recently been reported to mediate the non-genomic action of estrogen in different types of cells and tissues. G-1 (1-[4-(6-bromobenzo[1,3] dioxol-5yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinolin-8-yl]-ethanone) was developed as a potent and selective agonist for GPER. G-1 has been shown to induce the expression of genes and activate pathways that facilitate cancer cell proliferation by activating GPER. Here we demonstrate that G-1 has an anticancer potential with a mechanism similar to vinca alkaloids, the commonly used chemotherapy drugs. We found that G-1 blocks tubulin polymerization and thereby interrupts microtubule assembly in ovarian cancer cells leading to the arrest of cell cycle in the prophase of mitosis and the suppression of ovarian cancer cell proliferation. G-1 treatment also induces apoptosis of ovarian cancer cells. The ability of G-1 to target microtubules to suppress ovarian cancer cell proliferation makes it a promising candidate drug for treatment of ovarian cancer.

The in vitro study of ursolic acid and oleanolic acid inhibiting cariogenic microorganisms as well as biofilm

OBJECTIVE

The aim of this study was to examine the effect of ursolic acid (UA) and oleanolic acid (OA), triterpenoid compounds that are isolated from many edible and medicinal plants, on cariogenic microorganisms and biofilms.

METHODS

A microtitre plate dilution assay was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of UA and OA against two Actinomyces spp. and four Streptococcus spp. The antibacterial activity of UA and OA was assessed by crystal violet staining, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).

RESULTS

UA and OA displayed differential antibacterial activities against the six tested bacteria, with UA showing greater antibacterial activity than OA. Furthermore, the two drugs had greater antibacterial activity against Actinomyces spp. than Streptococcus spp. UA and OA at 1/4 MIC can reduce bacterial biofilm formation, whereas higher UA concentrations displayed antibacterial activity against Actinomyces viscosus and Streptococcus mutans in mature biofilms. For instance, 2.0 mg ml(-1) UA was sufficient to kill an A. viscosus biofilm.

CONCLUSIONS

UA and OA inhibit the growth of cariogenic microorganisms, which suggests that UA and OA have considerable potential as antibacterial agents for dental caries prevention.