Capturing antibacterial natural products with in silico techniques.

The aim of the present study was to index natural products in order to facilitate the discovery of less expensive antibacterial therapeutic drugs. Thus, for modeling purposes, the present study utilized a set of 628 antibacterial drugs, representing the active domain, and 2,892 natural products, representing the inactive domain. In addition, using the iterative stochastic elimination algorithm, 36 unique filters were identified, which were then used to construct a highly discriminative and robust model tailored to index natural products for their antibacterial bioactivity. The area attained under the curve was 0.957, indicating a highly discriminative and robust prediction model. Utilizing the proposed model to virtually screen a mixed set of active and inactive substances enabled the present study to capture 72% of the antibacterial drugs in the top 1% of the sample, yielding an enrichment factor of 72. In total, 10 natural products that scored highly as antibacterial drug candidates with the proposed indexing model were reported. PubMed searches revealed that 2 molecules out of the 10 (caffeine and ricinine) have been tested and identified as showing antibacterial activity. The other 8 phytochemicals await experimental evaluation. Due to the efficiency and rapidity of the proposed prediction model, it could be applied to the virtual screening of large chemical databases to facilitate the drug discovery and development processes for antibacterial drug candidates.

Detection of Ureaplasma Species by a Semi-Quantitative PCR Test in Urine Samples: Can It Predict Clinical Significance?

BACKGROUND: Ureaplasma species (Usp) are the most prevalent genital Mycoplasma isolated from the urogenital tract of both men and women. Usp may be commensals in the genital tract but may also be contributors to a number of pathological conditions of the genital tract. Because they can also just colonize the genital tract of healthy people, their pathogenic role can be difficult to prove. OBJECTIVES: The aim of the study was to evaluate the efficacy of a quantitative polymerase chain reaction (qPCR) method for the discrimination between infection and colonization by measuring prevalence of Usp in asymptomatic versus symptomatic patients. METHODS: Urine samples were tested for U. parvum and U. urealyticum using a semi-quantitative multiplex PCR technique for sexually transmitted diseases (Anyplex™ STI-7 Detection Kit, Seegene, South Korea). A total of 250 symptomatic and 250 asymptomatic controls were included. RESULTS: A strong positive result for U. parvum was significantly more prevalent in symptomatic compared to asymptomatic patients. This finding was observed especially in women and in the young group (15-35 years of age). No significant differences were observed between the prevalence in symptomatic and asymptomatic patients of U. parvum with low strength of positivity and for U. urealyticum in all groups by age, gender, and strength of positivity. CONCLUSIONS: The significant difference between the symptomatic and asymptomatic group in the highest positivity group for U. parvum using the Anyplex™ STI-7 detection kit in urine may indicate a high probability of infection rather than colonization, especially in women and young patients.

Inhibitory capacity of Rhus coriaria L. extract and its major component methyl gallate on Streptococcus mutans biofilm formation by optical profilometry: Potential applications for oral health.

Streptococcus mutans (S. mutans) bacterium is the most well recognized pathogen involved in pathogenesis of dental caries. Its virulence arises from its ability to produce a biofilm and acidogenicity, causing tooth decay. Discovery of natural products capable to inhibit biofilm formation is of high importance for developing health care products. To the best of our knowledge, in all previous scientific reports, a colorimetric assay was applied to test the effect of sumac and methyl gallate (MG) on S. mutans adherence. Quantitative assessment of the developed biofilm should be further performed by applying an optical profilometry assay, and by testing the effect on both surface roughness and thickness parameters of the biofilm. To the best of our knowledge, this is the first study to report the effect of sumac extract and its constituent MG on biofilm formation using an optical profilometry assay. Testing antibacterial activity of the sumac extract and its fractions revealed that MG is the most bioactive component against S. mutans bacteria. It reduced S. mutans biofilm biomass on the polystyrene surface by 68­93%, whereas 1 mg/ml MG was able to decrease the biofilm roughness and thickness on the glass surface by 99%. MG also prevented a decrease in pH level by 97%. These bioactivities of MG occurred in a dose­dependent manner and were significant vs. untreated bacteria. The findings are important for the development of novel pharmaceuticals and formulations of natural products and extracts that possess anti­biofilm activities with primary applications for oral health, and in a broader context, for the treatment of various bacterial infections.

From medicinal plant extracts to defined chemical compounds targeting the histamine H4 receptor: Curcuma longa in the treatment of inflammation.

OBJECTIVES: The aim was to evaluate the activity of seven medicinal, anti-inflammatory plants at the hH4R with focus on defined chemical compounds from Curcuma longa. MATERIALS: Activities were analyzed with membrane preparations from Sf9 cells, transiently expressing the hH4R, Gαi2 and Gß1γ2 subunits. METHODS: From the methanolic extract of C. longa curcumin (1), demethoxycurcumin (2) and bis(4-hydroxy-cinnamoyl)methane (3) were isolated, purified with HPLC (elution-time 10.20, 9.66, 9.20 min, respectively) and together with six additional extracts, were characterized via radioligand binding studies at the hH4R. RESULTS: Compounds from C. longa were the most potent ligands at the hH4R. They exhibited estimated K i values of 4.26-6.26 µM (1.57-2.31 µg/mL) (1); 6.66--8.97 µM (2.26-3.04 µg/mL) (2) and 10.24-14.57 µM (3.16-4.49 µg/mL) (3) (95% CI). The estimated K i value of the crude extract of curcuma was 0.50-0.81 µg/mL. Fractionated curcumin and the crude extract surpassed the effect of pure curcumin with a K i value of 5.54 µM or 2.04 µg/mL [95% CI (4.47-6.86 µM), (1.65-2.53 µg/mL)]. CONCLUSION: Within this study, defined compounds of C. longa were recognized as potential ligands and reasonable lead structures at the hH4R. The mode of anti-inflammatory action of curcumin was further elucidated and the role of extracts in traditional phytomedicine was strengthened.

In vitro and in vivo properties of a fully human IgG1 monoclonal antibody that combats multidrug resistant Pseudomonas aeruginosa.

The development of an anti-bacterial drug in the form of a monoclonal antibody (mAb) targeting an exposed virulence factor, represents an innovative therapeutic strategy. Consequently, a fully human IgG1 mAb (LST-007) targeting Pseudomonas aeruginosa (PA) flagellin type b was recombinantly expressed and characterized in vitro and in an infection model driven by a multidrug resistant (MDR) PA strain. LST-007 demonstrated a highly specific binding towards whole PA bacteria harboring flagellin type b and its recombinant counterpart, with a K(D) of 7.4x10(-10) M. In bioactivity assays, LST-007 or titers of Cmax sera derived from pharmacokinetic studies, markedly attenuated PA motility in an equipotent manner. In vivo, parenteral LST-007 (20 mg/kg) given as a single or double-dosing paradigm post-infection, afforded survival (up to 75% at Day 7) in a lethal model of pneumonia driven by the intratracheal (i.t.) instillation of an LD(80) of the MDR PA isolate. This protective effect was markedly superior to that of imipenem (30% survival at Day 7) and totally devoid with an irrelevant, human isotype mAb. These data lay credence that LST-007 may be a valuable adjunct to the limited list of anti-bacterials that can tackle MDR PA strains, thereby warranting its continued development for eventual clinical evaluation.

Colony to colorimetry in 6 h: ELISA detection of a surface-expressed Pseudomonas aeruginosa virulence factor using immobilized bacteria.

A rapid ELISA employing intact Pseudomonas aeruginosa (PA) is described that allows discrimination between strains harboring flagellin type a or b. All 52 PA strains known to harbor flagellin type b were positive in this ELISA when screened with a fully human monoclonal antibody (LST-007) targeting flagellin type b. Completion of this assay in only 6 h, from picking a single bacterial colony to a colorimetric product, could easily be adapted to a clinical laboratory setting and permit the appropriate choice of therapeutic monoclonal antibody versus its homologous flagellin target in PA-infected patients.