Antimicrobial Activity of Pregnenolone in vitro

The antimicrobial effect of pregnenolone on clinical and reference strains of Escherichia coli and Staphylococcus aureus was tested. Pregnenolone was found to have inhibitory activity against all tested bacterial strains. Slightly higher sensitivity is shown by the strains of S. aureus. When applied directly, pregnenolone has a weak antimicrobial effect due to its very low water solubility, as it is in oleose state because the formulation studied in this experiment contains tocopherol (a fat-soluble vitamin) as a co-solvent. When emulsified with lecithin, as well as with methanol, its solubility in water increases and penetrates over a longer distance in the agar around the points of its application. Applied as an emulsion, it shows significantly higher inhibitory activity against E. coli and S. aureus. Even the non-emulsified version should still be useful in vivo due to the fact that intracellular environments are much more lipophilic than serum, the target of most antimicrobial substances is the intracellular space, and non-emulsified pregnenolone has been shown to have very high intracellular uptake.

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In Vitro Coliform Resistance to Bioactive Compounds in Urinary Infection, Assessed in a Lab Catheterization Model

Applied Sciences ◽

10.3390/app11094315 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4315

Author(s):

Emanuel Vamanu ◽

Laura Dorina Dinu ◽

Cristina Mihaela Luntraru ◽

Alexandru Suciu

Keyword(s):

Urinary Tract ◽

Bioactive Compounds ◽

Urinary Tract Infections ◽

Antimicrobial Effect ◽

Biologically Active ◽

Bacterial Strains ◽

E Coli ◽

Functional Product ◽

Tract Infections

Bioactive compounds and phenolic compounds are viable alternatives to antibiotics in recurrent urinary tract infections. This study aimed to use a natural functional product, based on the bioactive compounds’ composition, to inhibit the uropathogenic strains of Escherichia coli. E. coli ATCC 25922 was used to characterize the IVCM (new in vitro catheterization model). As support for reducing bacterial proliferation, the cytotoxicity against a strain of Candida albicans was also determined (over 75% at 1 mg/mL). The results were correlated with the analysis of the distribution of biologically active compounds (trans-ferulic acid-268.44 ± 0.001 mg/100 g extract and an equal quantity of Trans-p-coumaric acid and rosmarinic acid). A pronounced inhibitory effect against the uropathogenic strain E. coli 317 (4 log copy no./mL after 72 h) was determined. The results showed a targeted response to the product for tested bacterial strains. The importance of research resulted from the easy and fast characterization of the functional product with antimicrobial effect against uropathogenic strains of E. coli. This study demonstrated that the proposed in vitro model was a valuable tool for assessing urinary tract infections with E. coli.

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Monoclonal antibodies specific to a Ca2+-bound form of lipocortin I distinguish its Ca2+-dependent phospholipid-binding ability from its ability to inhibit phospholipase A2

Biochemical Journal ◽

10.1042/bj2690709 ◽

1990 ◽

Vol 269 (3) ◽

pp. 709-715 ◽

Cited By ~ 11

Author(s):

H Hayashi ◽

M K Owada ◽

S Sonobe ◽

K Domae ◽

T Yamanouchi ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Phospholipase A2 ◽

Inhibitory Activity ◽

Biological Effects ◽

Free Form ◽

E Coli ◽

Phospholipid Binding ◽

Ef Hand

Lipocortin I, a Ca2(+)-and phospholipid-binding protein without EF-hand structures, has many biological effects in vitro. Its actual role in vivo, however is unknown. We obtained and characterized five monoclonal antibodies to lipocortin I. Two of these monoclonal antibodies (L2 and L4-MAbs) reacted with the Ca(+)-bound form of lipocortin I, but not with the Ca2(+)-free form, both in vivo and in vitro. Lipocortin I required greater than or equal to 10 microM-Ca2+ to bind the two antibodies, and this Ca2+ requirement was not affected by phosphatidylserine. L2-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I and inhibited its binding to Escherichia coli membranes and to phosphatidylserine in vitro. L4-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I, but did not affect its binding to E. coli membranes or to phosphatidylserine. These findings indicated that the inhibition of phospholipase A2 by lipocortin I was not simply due to removal or capping of the substrates in E. coli membranes. Furthermore, an immunofluorescence study using L2-MAb showed the actual existence of Ca2(+)-bound form of lipocortin I in vivo.

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The Development of Novel Organotin Anti-Tumor Drugs: Structure and Activity

Metal-Based Drugs ◽

10.1155/mbd.1998.179 ◽

1998 ◽

Vol 5 (4) ◽

pp. 179-188 ◽

Cited By ~ 85

Author(s):

Dick de Vos ◽

Rudolph Willem ◽

Marcel Gielen ◽

Kyra E. van Wingerden ◽

Kees Nooter

Keyword(s):

Water Solubility ◽

Solubility In Water ◽

In Vivo Testing ◽

Polar Substituents ◽

Tumor Drugs ◽

Separate Class ◽

Structure And Activity ◽

Very High

An overview of the development of anti-tumor organotin derivatives in selected classes of compounds is presented and discussed. High to very high in vitro activity has been found, sometimes equaling that of doxorubicin. Solubility in water is an important issue, dominating the in vivo testing of compounds with promising in vitro properties. The cytotoxicity of the compounds was increased by the presence of a bulky group, an active substituent or one or more polar substituents. Polar substituents may also improve the water solubility. Although organotin derivatives constitute a separate class of compounds, the comparison with cisplatin is inevitable. Among the observed toxicities, neurotoxicity, known from platinum cytostatics, and gastrointestinal toxicity, typical for many oncology drugs, have been detected. Further research to develop novel, useful organotin anti-tumor compounds should be carried out.

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Antimicrobial Effect and Cytotoxic Evaluation of Mg-Doped Hydroxyapatite Functionalized with Au-Nano Rods

Molecules ◽

10.3390/molecules26041099 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1099

Author(s):

Domenico Franco ◽

Giovanna Calabrese ◽

Salvatore Petralia ◽

Giulia Neri ◽

Carmelo Corsaro ◽

...

Keyword(s):

Bone Matrix ◽

Antibacterial Properties ◽

Antimicrobial Effect ◽

Cell Number ◽

Bacterial Reduction ◽

E Coli ◽

Good Biocompatibility ◽

Inorganic Mineral

Hydroxyapatite (HA) is the main inorganic mineral that constitutes bone matrix and represents the most used biomaterial for bone regeneration. Over the years, it has been demonstrated that HA exhibits good biocompatibility, osteoconductivity, and osteoinductivity both in vitro and in vivo, and can be prepared by synthetic and natural sources via easy fabrication strategies. However, its low antibacterial property and its fragile nature restricts its usage for bone graft applications. In this study we functionalized a MgHA scaffold with gold nanorods (AuNRs) and evaluated its antibacterial effect against S. aureus and E. coli in both suspension and adhesion and its cytotoxicity over time (1 to 24 days). Results show that the AuNRs nano-functionalization improves the antibacterial activity with 100% bacterial reduction after 24 h. The toxicity study, however, indicates a 4.38-fold cell number decrease at 24 days. Although further optimization on nano-functionalization process are needed for cytotoxicity, these data indicated that Au-NRs nano-functionalization is a very promising method for improving the antibacterial properties of HA.

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Influence of the Sodium Salt of 3α,7α-Dihydroxy-12-Oxo-5β-Cholanate on Antimicrobial Activity of Ampicillin In Vitro

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.81166 ◽

2018 ◽

Vol 44 (1) ◽

pp. 6

Author(s):

Ljiljana Suvajdžić ◽

Slobodan Gigov ◽

Aleksandar Rašković ◽

Srđan Stojanović ◽

Maja Bekut ◽

...

Keyword(s):

Antimicrobial Activity ◽

Sodium Salt ◽

Antimicrobial Effect ◽

In Vivo Studies ◽

Bacterial Suspension ◽

Commercial Preparation ◽

E Coli ◽

Colony Forming Units

Background: Multiple resistances to antibiotics are an emergent problem worldwide. Scientists intensively search for new substances with the antimicrobial potential or the mode to restore the activity of old-generation antibiotics. Ampicillin is the antibiotic with the expanded range of antimicrobial activity, but its use has decreased due to the poor absorption and highly developed resistance. In vivo studies showed that ampicillin has better absorption and bioavailability if combined with bile acid salts. The aim of this study was to examine antimicrobial effects of ampicillin alone and its combination with semisynthetic monoketocholic acid salt (MKH) in vitro.Materials, Methods & Results: In this study, commercial preparation of ampicillin and sodium salt of 3α,7α-dihydroxy-12oxo-5β-cholanate were used. Their effects were evaluated on Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium), obtained from urine specimens of dogs with clinically manifested cystitis. The first two investigated strains were ampicillin-sensitive, while E. faecium was resistant to ampicillin. Modified macrodilution method according to Clinical and Laboratory Standards Institute Guidelines (M7-A8) was performed. Bacterial suspension equivalent to 0.5 McFarland was prepared in saline, compared to the standard (Biomerieux) ad oculi. The density was checked spectrophotometrically at a wavelength of 625 nm and adjusted if necessary to the desired absorbance from 0.08 to 0.1. The resultant suspension was diluted 1:100 and inoculated in test tubes. Number of bacteria was counted on Petri plates using dilutions from 10-3 to 10-7 in order to obtain valid and countable plates. One hundred microliters of appropriate dilutions were aseptically plated in triplicate onto nutrient agar. Plates were incubated on 37°C for 72 h, under aerobic conditions. The number of colony forming units (CFU) was determined by direct counting. As a valid for enumeration, we took plates with 30 to 300 CFU. Percentage of killed bacteria for ampicillin was from 69.33-95.19% for E. coli, 87.1296.92% for E. faecalis and 7.20-33.30% for E. faecium. Ampicillin applied in the combination with MKH killed 99.99% to 100% of E. coli, 94.59% to 99.91% of E. faecalis and 31.73% to 64.76% of E. faecium. Mean percentage of killed bacteria for ampicillin was 81.93% for E. coli, 91.64% for E. faecalis, and 18.13% for E. faecium, while in combination with MKH percentage was 99.96% for E. coli, 98.23% for E. faecalis and 47.54% for E. faecium.Discussion: Results are presented as pharmacological minimal inhibitory concentration (MIC) values. Ampicillin was applied at the concentration higher than the therapeutic one, which could explain high MIC values for E. coli and E. faecalis. The combination of ampicillin with MKH showed the best improvement of antimicrobial effect on E. faecium (Δ = 29.41%), isolate that was resistant to ampicillin when applied alone. In all the investigated isolates, the combinations with MKH were more effective than ampicillin administered alone. It seems that MKH demonstrates a synergistic antimicrobial activity with ampicillin in vitro, which considerably decreases MIC values for all investigated isolates. These results implicate that MKH could restore the previous activity of ampicillin against some bacteria, which could be a significant benefit for clinical practice.

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Copper(II) mixed-ligand complexes containing 1, 10-phenanthroline, adenine and thymine: Synthesis, characterization and antibacterial activities

10.31221/osf.io/d95yt ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Copper Complexes ◽

Antimicrobial Agents ◽

Conductivity Measurement ◽

Antibacterial Activities ◽

Antimicrobial Activities ◽

Bacterial Strains ◽

E Coli ◽

In Vivo Cytotoxicity

New copper complexes, [Cu(phen)2(Thy)]2Cl and [Cu(phen)2(Ad)]2Cl (phen = 1,10-phenantroline, Ad (Adenine, a purine nucleobase) and Thy (Thymine, a pyrimidine nucleobase)), were synthesized and characterized by atomic absorption spectroscopy (AAS), conductivity measurement, UV-visible and infrared (IR) techniques. The complexes were tested for their antimicrobial activity against two gram positive and two gram negative bacterial strains. The results of in vitro antimicrobial activities were compared with the commercially available antimicrobial agents (ciprofloxacin and chloramphenicol). This comparative study has demonstrated that [Cu(phen)2(Thy)]2Cl inhibited the growth of methicillin resistant Staphylococcus aureous (MRSA), Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumonia) better than chloramphenicol by 11.25%, 19.41% and 25.35%, respectively. It also showed better activities than ciprofloxacine on MRSA and K. pneumoniae by 2.50% and 12.13%, respectively. Similarly, [Cu(phen)2(Ad)]2Cl demonstrated better inhibitions than chloramphenicol against MRSA, E. coli and K. pneumoniae by 11.24%, 2.48% and 9.06%, respectively. Therefore, after in vivo cytotoxicity investigations, these complexes could be considered as potential antimicrobial agents.

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The Disulfide Bond of the Peptide Thanatin Is Dispensible for Its Antimicrobial ActivityIn VivoandIn Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00041-16 ◽

2016 ◽

Vol 60 (7) ◽

pp. 4283-4289 ◽

Cited By ~ 16

Author(s):

Bo Ma ◽

Chao Niu ◽

Ying Zhou ◽

Xiaoyan Xue ◽

Jingru Meng ◽

...

Keyword(s):

Disulfide Bond ◽

Umbilical Vein ◽

Low Cost ◽

Survival Rates ◽

Antimicrobial Activities ◽

Bacterial Strains ◽

Content Type ◽

E Coli

ABSTRACTThanatin (THA) displays potent antibiotic activity, especially against extended-spectrum-β-lactamase (ESBL)-producingEscherichia colibothin vitroandin vivo, with minimal hemolytic toxicity and satisfactory stability in plasma. However, the high cost of thanatin significantly limits its development and clinical application. To reduce the cost of peptide synthesis, a formulation of cyclic thanatin (C-thanatin) called linear thanatin (L-thanatin) was synthesized and its activity was evaluatedin vivoandin vitro. Results showed that C-thanatin and L-thanatin MICs did not differ against eight Gram-negative and two Gram-positive bacterial strains. Furthermore, the survival rates of ESBL-producing-E. coli-infected mice were consistent after C-thanatin or L-thanatin treatment at 5 or 10 mg/kg of body weight. Neither C-thanatin nor L-thanatin showed toxicity for human red blood cells (hRBCs) and human umbilical vein endothelial cells (HUVECs) at a concentration as high as 256 μg/ml. Results of circular dichroism spectroscopy indicated that the secondary structure of L-thanatin is extremely similar to that of C-thanatin. Membrane permeabilization and depolarization assays showed that C-thanatin and L-thanatin have similar abilities to permeabilize the outer and inner membranes and to induce membrane depolarization in ESBL-producingE. coli. However, neither of them caused significant HUVEC membrane permeability. These findings indicate that the two peptides have similar effects on bacterial cell membranes and that the disulfide bond in thanatin is not essential for its antimicrobial activitiesin vivoandin vitro. L-thanatin is thus a promising low-cost peptide candidate for treating ESBL-producingE. coliinfections.

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Evaluation of antimicrobial activity of magnesium oxide nanocomposite film in combination with ε-poly-L-lysine against Foodborne pathogens in vacuum packaged beef

10.21203/rs.3.rs-294697/v1 ◽

2021 ◽

Author(s):

Masumeh Samadi ◽

Seyed Shahram Shekarforoush ◽

Hamid Reza Gheisari

Keyword(s):

Antimicrobial Activity ◽

Magnesium Oxide ◽

Culture Media ◽

Antimicrobial Effect ◽

Inhibitory Effect ◽

Melt Mixing ◽

E Coli ◽

Mgo Nanoparticle

Abstract Background: The aim of this study was to evaluate the antimicrobial activity of magnesium oxide nanocomposite (MgO NC) film based on Low-density polyethylene (LDPE) alone or in combination with three concentrations of ε-poly-L-lysine (500, 1000 and 2000 µg/ml) on Escherichia coli O157:H7 and Listeria monocytogenes in culture media and fresh beef. Methods: MgO NC film were prepared by melt mixing LDPE and MgO nanoparticle in the extruder. For in vitro antibacterial analysis, the MgO NC film alone or in combination with polylysine were evaluated in tryptic soy broth for 5 days at 37 °C. For in vivo analysis, beef samples were inoculated with the selected bacteria and packaged in MgO NC film under vacuum and stored at 4 °C and evaluated for up to 20 days. Results: Polylysine had an antibacterial effect against E. coli and L. monocytogenes in TSB. But MgO NC film had a bacteriostatic effect only against E. coli. MgO NC film inhibited the growth of E. coli on the surface of beef samples. Pollysine at concentrations of 500 µg/ml or more showed inhibitory activity against E. coli and L. monocytogenes in beef samples. No additional reduction was observed by combining the different concentrations of polylysine with MgO NC film.Conclusions: Polylysine at all concentrations had an inhibitory effect on E. coli and L. monocytogenes in the culture medium and beef. Although the migration of MgO nanoparticle from the film to beef was very low, but as it has little antimicrobial effect, it is not recommended as a suitable package for improving the safety of raw beef.

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Antibacterial and molecular docking studies of newly synthesized nucleosides and Schiff bases derived from sulfadimidines

Scientific Reports ◽

10.1038/s41598-021-97297-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hamada H. Amer ◽

Essam Hassan Eldrehmy ◽

Salama Mostafa Abdel-Hafez ◽

Youssef Saeed Alghamdi ◽

Magdy Yassin Hassan ◽

...

Keyword(s):

Molecular Docking ◽

Schiff Bases ◽

Docking Studies ◽

Bacterial Strains ◽

Antibacterial Effects ◽

Molecular Docking Studies ◽

E Coli ◽

Inhibition Zones

AbstractA new series of nucleosides, moieties, and Schiff bases were synthesized from sulfadimidine. Infrared (IR), 1HNMR, 13C NMR, and mass spectrometry techniques and elemental analysis were employed to elucidate the synthesized compounds. The prepared analogues were purified by different chromatographic techniques (preparative TLC and column chromatography). Molecular docking studies of synthesized compounds 3a, 4b, 6a, and 6e demonstrated the binding mode involved in the active site of DNA gyrase. Finally, all synthesized compounds were tested against selected bacterial strains. The most effective synthesized compounds against S. aureus were 3a, 4d, 4b, 3b, 3c, 4c, and 6f, which exhibited inhibition zones of inhibition of 24.33 ± 1.528, 24.67 ± 0.577, 23.67 ± 0.577, 22.33 ± 1.528, 18.67 ± 1.528 and 19.33 ± 0.577, respectively. Notably, the smallest zones were observed for 4a, 6d, 6e and 6g (6.33 ± 1.528, 11.33 ± 1.528, 11.67 ± 1.528 and 14.66 ± 1.155, respectively). Finally, 6b and 6c gave negative zone values. K. pneumoniae was treated with the same compounds and the following results were obtained. The most effective compounds were 4d, 4c, 4b and 3c, which showed inhibition zones of 29.67 ± 1.528, 24.67 ± 0.577, 23.67 ± 1.155 and 19.33 ± 1.528, respectively, followed by 4a and 3d (15.33 ± 1.528 for both), while moderate results (13.67 ± 1.155 and 11.33 ± 1.528) were obtained for 6f and 6g, respectively. Finally, 6a, 6b, 6c, 3a, and 3b did not show any inhibition. The most effective compounds observed for the treatment of E. coli were 4d, 4b, 4c, 3d, 6e and 6f (inhibition zones of 26.33 ± 0.577, 21.67 ± 1.528, 21.67 ± 1.528, 19.67 ± 1.528, 17.67 ± 1.155 and 16.67 ± 1.155, respectively). Compounds 3b, 3c, 6a, 6c, and 6g gave moderate results (13.67 ± 1.528, 12.67 ± 1.528, 11.33 ± 0.577, 15.33 ± 1.528 and 12.67 ± 1.528, respectively), while 6b showed no effect. The MIC values against S. aureus ranged from 50 to 3.125 mg, while those against E. coli and K. pneumoniae ranged from 50 to 1562 mg. In vitro, the antibacterial effects were promising. Further research is required to study the in vivo antibacterial effects of these compounds and determine therapeutic doses.

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In Vitro Digestion of Chestnut and Quebracho Tannin Extracts: Antimicrobial Effect, Antioxidant Capacity and Cytomodulatory Activity in Swine Intestinal IPEC-J2 Cells

Animals ◽

10.3390/ani10020195 ◽

2020 ◽

Vol 10 (2) ◽

pp. 195 ◽

Cited By ~ 4

Author(s):

Serena Reggi ◽

Carlotta Giromini ◽

Matteo Dell’Anno ◽

Antonella Baldi ◽

Raffaella Rebucci ◽

...

Keyword(s):

Antioxidant Capacity ◽

Inhibitory Activity ◽

Antimicrobial Effect ◽

In Vitro Digestion ◽

Intestinal Epithelial ◽

E Coli ◽

Growth Inhibitory ◽

Growth Inhibitory Activity ◽

Coli Growth

Quebracho (Qu) and chestnut (Ch) are natural sources of tannins and they are currently used in animal nutrition as feed ingredients. However, to date the bio-accessibility, antimicrobial, antioxidant, and intestinal epithelial cell stimulatory doses of Qu and Ch have not been determined. Our study investigates the antioxidant and E. coli F4+ and F18+ growth inhibitory activity of Qu, Ch, and their combinations after solubilization in water (to evaluate the already bio-accessible molecules) and after simulated gastro-intestinal digestion in vitro. The effect of an in vitro digested Ch and Qu combination was also tested on intestinal epithelial IPEC-J2 cells experimentally stressed with hydrogen peroxide (H2O2) and Dextran Sodium Sulfate (DSS). The results showed that undigested Qu and Ch alone, and in combination, exerted a valuable antioxidant capacity and E. coli F4+ and F18+ growth inhibitory activity. The concentration of 1200 µg/mL exhibited the highest E. coli growth inhibitory activity for all the samples tested. In addition, after in vitro digestion, Qu and Qu50%–Ch50% maintained E. coli growth inhibitory activity and a modest antioxidant capacity. Three hours pre-treatment with in vitro digested Qu50%–Ch50% counteracted the H2O2 and DSS experimentally-induced stress in the intestinal IPEC-J2 cells. Ch and Qu tannin extracts, particularly when combined, may exert E. coli F4+ and F18+ growth inhibitory activity and valuable antioxidant and cell viability modulation activities.

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