Minimum Bacterial Concentration Research Articles

Lemongrass (Cymbopogon citratus) oil nanoparticle synthesis, characteristic, and evaluation of antibacterial and antifungal effects and the influence on hardness of acrylic resin

Context: Acrylic resin is used in dentistry as a removable denture base. It can cause various pathologies when not properly cleaned. One of the pathologies is denture stomatitis caused by Candida albicans and Streptococcus mutans accumulation on the acrylic resin surface. Therefore, microbial agents such as denture cleansers are needed. Aims: To evaluate the characteristics of lemongrass (Cymbopogon citratus) nanoparticles as a better antibacterial and antifungal herbal ingredient and their relationship with acrylic hardness. Methods: C. citratus oil nanoparticles (LON) were synthesized and analyzed by transmission electron microscopy (TEM). Electrospray ionization tandem mass spectrometry (ESI-MS) analysis was used to analyze the characteristics of LON bioactive components. Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) against C. albicans and S. mutans and mechanical hardness test of acrylic were performed. Results: The LON concentration of MIC and MBC against C. albicans and S. mutans was 25 and 100%, respectively. One-way ANOVA showed no significant difference between groups of LON with different concentrations (p=0.687). A paired t-test showed significant differences in acrylic resin hardness before and after treatment of LON with 100% (p=0.022) and 50% (p=0.021) concentration. There was no significant difference in hardness before and after treatment of other concentrations of LON and chlorhexidine as positive control. Conclusions: LON treatment on acrylic resin decreased the growth of C. albicans and S. mutans without altering the mechanical properties (hardness).

Synthesis, biological evaluation, molecular docking analyses, and ADMET study of azo derivatives containing 1-naphthol against MβL-producing S. maltophilia

Stenotrophomonas maltophilia is a model organism exhibiting intrinsic antibiotic resistance, primarily due to its production of Mβ-lactamase enzymes that inactivate β-lactam antibiotics. This study aims to synthesize an azo derivative containing an oxazepine ring as a potential inhibitor of Mβ-lactamase. The molecular docking results revealed that the binding energies of the Mβ-lactamases ranged from − 5.95 to − 6.09 kcal/mol, indicating favourable interactions with the synthesized compounds. Two compounds were prepared: the first via aldol condensation of (A1) with p-hydroxybenzaldehyde to form (K1) and the second through Azo-Schiff base formation from 3,5-dimethylaniline, resulting in (L2) and (L18). Characterization of these compounds was conducted via FT-IR, CHN, 1H NMR, and 13C NMR spectroscopy. Antimicrobial activity was assessed through minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) tests, which yielded values ranging from 1.19 ± 1 to 0.02 µg/mL and from 1.12 ± 1 to > 0.04 µg/mL, respectively. Notably, the MBC/MIC ratios indicated that L2 and L18 exhibited significant bactericidal activity. In silico analysis via MOE 2015 software allowed us to determine the binding poses and energies of the synthesized inhibitors against Mβ-lactamase (PDB ID: 6UAF). The most stable conformation from the docking results was selected for further evaluation. Compared with standard ceftazidime, the synthesized compounds significantly inhibited Mβ-lactamase activity. Additionally, ADMET analysis indicated favourable pharmacokinetic profiles and low toxicity, suggesting promising oral drug-like properties for the synthesized molecules.

Preliminary Study to Assess the Antioxidant and Antibacterial Activity of Extracts from the Leaves of Morelia Senegalensis (A Rich)

frican populations rely heavily on traditional medicine, which uses plants to treat human and animal diseases. However, scientific validation of this empirical knowledge concerning the efficacy, toxicity and dosage of the proposed treatments is urgently needed. The aim of this study was to evaluate the antioxidant and antibacterial activity of Morelia senegalensis leaf extracts on the 2,2-diphenyl-1-picrylhydrawyl (DPPH) radical and the (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid) ABTS cation radical and on four reference bacterial strains (E. coli 25922, E. coli 35218, E. faecalis 29212 and S. aureus 29213) using protocols already described in the literature. The phytochemical screening test revealed the presence of flavonoids, alkaloids, tannins, saponins, reducing compounds and sterols in Morelia senegalensis leaves. All the extracts showed antioxidant activity to varying degrees. The most active ethyl acetate (AE) extract had half-maximum inhibition concentration (IC50 )of 0.33 and 0.62 mg/mL for the ABTS and DPPH tests respectively, followed by DCM and EB extracts with IC50 of 0.86 and 0.88 mg/mL for the ABTS test respectively, while the vitamin C used as a reference was more active with IC50 of 0.04 and 0.06 mg/mL. Antibacterial activity showed inhibition diameters ranging from 7 to 16 mm depending on the concentration and strain considered. The ethyl acetate fraction was the most active on S aureus 29213 with an inhibition diameter of 16 mm at 50 mg/mL. These interesting results were confirmed by the Minimal Inhibitory Concentration inhibitory (MIC) and Minimal Bacterial Concentration (MBC) studies, which showed that all the extracts had a bactericidal effect on all the studied strains. Morelia senegalensis plant has shown promising preliminary results in the treatment of bacterial infections. Further studies are needed to isolate and characterize the secondary metabolites contained in the leaves of this plant.

Single Atom Engineered Antibiotics Overcome Bacterial Resistance

AbstractThe outbreak of antibiotic‐resistant bacteria, or “superbugs”, poses a global public health hazard due to their resilience against the most effective last‐line antibiotics. Identifying potent antibacterial agents capable of evading bacterial resistance mechanisms represents the ultimate defense strategy. This study shows that –the otherwise essential micronutrient– manganese turns into a broad‐spectrum potent antibiotic when coordinated with a carboxylated nitrogen‐doped graphene. This antibiotic material (termed NGA‐Mn) not only inhibits the growth of a wide spectrum of multidrug‐resistant bacteria but also heals wounds infected by bacteria in vivo and, most importantly, effectively evades bacterial resistance development. NGA‐Mn exhibits up to 25‐fold higher cytocompatibility to human cells than its minimum bacterial inhibitory concentration, demonstrating its potential as a next‐generation antibacterial agent. Experimental findings suggest that NGA‐Mn acts on the outer side of the bacterial cell membrane via a multimolecular collective binding, blocking vital functions in both Gram‐positive and Gram‐negative bacteria. The results underscore the potential of single‐atom engineering toward potent antibiotics, offering simultaneously a long‐sought solution for evading drug resistance development while being cytocompatible to human cells.

Effect of High-Pressure Processing on the Antioxidant and Antibacterial Properties of Honey

AbstractHigh pressure processing (HPP) have the potential to be used as an alternative to commercial thermal processing of honey. Its impact on the antioxidant and antibacterial properties of honey have yet to be understood properly. This study focuses on the effects of HPP on the antioxidant and antibacterial properties of honey. Six different honey samples were subjected to HPP at 400 and 600 MPa for 10 and 15 min. The antioxidant properties were measured in terms of total phenolic content, total flavonoid content, the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging assay. The antibacterial activity was measured as the minimum bacteriocidal and minimum bacterial inhibition concentration of honey against S. aureus, P. aeruginosa and E. coli. HPP decreased the total phenolic content and increased the total flavanoid content. There was an increase in the antibacterial activity of HPP honey against S. aureus, whereas no significant changes were observed against P. aeruginosa, and E. coli. It was evident that the changes in the antioxidant and antibacterial activity of honey samples were dependent on the HPP processing parameters and the type of honey.

Design, Synthesis and Antibacterial Assessment of Active (4-Arylazo-3-Methyl-2-Thienyl) 4-Antipyrine Ketones.

The chemicals formed from antipyrines are flexible organic building blocks that are employed in the development of pharmaceuticals. By diazotizing (4-arylazo-3-hydroxy-2-thienyl) 4-antipyrine ketones 1a, 1b and 1c and (4-arylazo-3-methyl-2-thienyl) 4-antipyrine ketones (2a, 2b and 2c) further replaced with six other coupling components, a broad spectrum of hybrid molecules have been created. Mass spectra, NMR, FTIR, and elemental analyses have all been used to confirm the structures of the synthesised compounds. The antimicrobial screening was investigated by agar well diffusion and diluting the broth technique against both Gram-negative and positive-tested bacterial strains. (3-methyl-5-(phenylamino)-4-(4-tolylazo)-2-thienyl) 4-antipyrine ketone (2a) was found to be superior to Ciprofloxacin against test strains: Acinetobacter sp (34.33±1.15 mm), Listeria monocytogenes (29.33±1.15 mm) and Streptococcus sp. (19.33±1.15 mm). Also, good to moderate activities were expressed as minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) which were recorded at 9±1 to 59.67±4.51 μg/mL and 16±4 to >512 μg/mL, respectively, using compounds 2a, 2b, and 2c. MBC/MIC ratio showed, that only, 2a and 2b have a bactericidal effect but other antipyrines with bacteriostatic strength. To conclude, it was suggested that the use of these novel synthesized (4-arylazo-3-methyl-2-thienyl) 4-antipyrine ketone derivatives molecules as a new chemical class of antimicrobial agents to perform new drug discovery in pharmaceutical preparations and medicinal research.

An in vitro evaluation of the efficacy of kaempferol as an antimicrobial agent on periodontal pathogens: An in vitro study

Aims: Kaempferol, a flavonoid found in many edible plants, has been attributed to having antimicrobial activity against microorganisms. The current work focused on ascertaining the minimum inhibitory concentration (MIC) and conducting time-kill analysis of pure kaempferol against periodontal pathogens, along with elucidation of the antiproteolytic effect of kaempferol against Porphyromonas gingivalis protease. Method: Kaempferol dissolved in dimethyl sulfoxide was tested against six standard periodontal pathogens, namely P. gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Candida albicans, to determine the minimum bacterial concentration (MBC), MIC, and conduct time-kill analysis using serial dilution and plating method. The gelatin liquefaction test was conducted to determine the antiproteolytic activity against P. gingivalis. Results: Kaempferol was found to exhibit bactericidal activity against all analyzed periodontal pathogens. The MBC ranged from 6.25 to 100 µL/mL (P. gingivalis and P. intermedia—6.25 µL/mL; T. forsythia and C. albicans—12.5 µL/mL; F. nucleatum—50 µL/mL; A. actinomycetemcomitans—100 µL/mL). MIC ranged from 3.12 to 50 µL/mL. Time-kill analysis demonstrated that the C. albicans was inhibited by 90% within the first 2 hours of incubation and P. gingivalis and F. nucleatum by 80% within 6 hours. Complete inhibition of protease activity was established at 12.5 µL/mL concentration of kaempferol. Conclusion: The study results demonstrated kaempferol’s antimicrobial efficacy against periodontal pathogens and its ability to inhibit protease activity in P. gingivalis. Kaempferol holds promise as a safer alternative to conventional antibiotics in the treatment of periodontitis, thus expanding the therapeutic options in antimicrobial strategies.

Screening and characterization of antagonistic Streptomyces sp. JS20 from marine sediment in Vaan Island

In the present study, we have isolated twenty four different Actinomycetia strains from marine sediment in Vaan Island, Tuticorin district (8.83639°N/78.21047°E), Tamil Nadu, India. Among these, the isolate JS20 has been identified as Streptomyces sp. JS20 by 16S rRNA phylogenetic analysis, which exhibited prominent antibacterial activity against panel of WHO priority pathogens mostly, MRSA a clinical pathogen. The bioassay guided fractionation dependent active compound exhibits RT at 3.0 with maximum UV absorption of 250 nm. Furthermore, FT-IR, 1H NMR, 13C NMR and LC-MS spectral analysis confirms the existence of polyketide metabolites with molecular mass of m/z 380.74 [M+Na]+ and m/z 397.00 [M+K]+ adducts. Minimum Inhibitory Concentration (MIC) and Minimum Bacterial Concentration (MBC) value of the purified compound against MRSA was found to be 7.81 µg/mL and 125 µg/mL respectively. Additionally, the anti-MRSA campaign of the purified compound was upheld qualitatively using the high content screening (HCS) and quantitatively by Flow Cytometry (FACS) analysis which indicates concentration of bactericidal activity increases when the concentration of the purified compound was increased. The action of bioactive compound was determined by cell morphology disruption on MRSA bacterial cells as results, the cytoplasm cellular contents and ATP leaky were ahead. Apart from these studies, NaCl tolerant, the multiple passage studies and post antibiotic effect of bioactive compound has been evaluated against the MRSA. Hence, the study revealed that the bioactive compound from the Streptomyces sp. JS20 can be used as a lead compound to inhibit the MRSA in future.

Lyophilized cell-free supernatants of Limosilactobacillus fermentum T0701 exhibited antibacterial activity against Helicobacter pylori

Helicobacter pylori is a prominent gastrointestinal pathogen associated with various gastrointestinal illnesses. It presents substantial health risks due to its antibiotic resistance. Therefore, it is crucial to identify alternative treatments for H. pylori infections. Limosilactobacillus spp exhibit probiotic properties with beneficial effects in humans; however, the mechanisms by which it counteracts H. pylori infection are unknown. This study aimed to evaluate the potential of Limosilactobacillus fermentum T0701 lyophilized cell-free supernatants (LCFS) against H. pylori. The LCFS has varying antimicrobial activities, with inhibition zones of up to 10.67 mm. The minimum inhibitory concentration and minimum bacterial concentration of LCFS are 6.25–25.00 mg/mL and 6.25 mg/mL to > 50.00 mg/mL, respectively, indicating its capability to inhibit H. pylori. There is morphological damage observed in H. pylori treated with LCFS. Additionally, H. pylori adhesion to AGS cells (human gastric adenocarcinoma epithelial cells) reduces by 74.23%, highlighting the LCFS role in preventing bacterial colonization. Moreover, LCFS exhibits no cytotoxicity or morphological changes in AGS cells, and with no detected virulence or antimicrobial resistance genes, further supporting its safety profile. L. fermentum T0701 LCFS shows promise as a safe and effective non-toxic agent against H. pylori, with the potential to prevent gastric colonization.

Fabrication of Silver Nanoparticles Using Acalypha paniculata Extract, AI-Based Interaction Analysis and Its Activity Explication

This study showcases eco-friendly silver nanoparticle synthesis using Acalypha paniculata herb and its biological activity. Artificial Intelligence (AI) tools are used to analyze the interaction between phytoconstituent and silver ion to find the capping and nanoparticle fabricating phytoconstituents. Ethanolic extract was added to silver nitrate solution and irradiated under sunlight until the formation of silver nanoparticles. These particles were sedimented, characterised by spectral technique and biological activity was measured. Finally, a Computational simulation algorithm was used to visualize the interactions of phytoconstituent and silver nanoparticles. Ultra Violet (UV)-visible spectrum revealed a visible peak at 420nm in the brownish solution, Dynamic Light Scattering (DLS) size of 54.7nm, spherical crystalline morphology of the nanoparticle by Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD) analysis. The synthesized silver nanoparticle antagonised Escherichia coli, and Bacillus cereus and showed the Minimum Inhibitory Concentration (MIC) of 65 µg/mL, and 78 µg/mL respectively and Minimum Bacterial Concentration (MBC) of 52.5 µg/mL for B.cereus and 61.5µg/mL for E.coli. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals IC50 was found to be 97.414 µg/mL and it revealed the dose-dependent antioxidant activity of phyto-capped silver particles. The cytotoxicity of fabricated nanoparticles was studied on Vero cells and the results indicate that IC50 of 47.28 µg/mL. Furthermore, an AI-based study concludes that Alloaromadendrene adsorbed highly by the Silver (Ag) ion compared to the nitrate with an affinity of -30.6755 kcal/mol. This research introduces an innovative, cost-effective method for stable Acalypha paniculata Silver Nanoparticles (AP-AgNPs) fabrication, crucial for diverse biomedical uses.

Effect of Moringa Oleifera Seed Extracts on Escherichia Coli

This work is to determine the effect of wonder plant (Moringa oleifera) seed extracts on Escherichia coli. E. coli was isolated, characterized and identified. The moringa seed extract was extracted and characterized, concentration was prepared, preparation of sensitivity disc with the extract, determination of minimum inhibitory concentration and minimum bacterial concentration of extract were done while antibiotics susceptibility test served as the control. The results show that ethanol/extract was highly effective followed by hot water/extract while cold water/extract was the least as the P>0.5. The extracts show promise as a natural antibacterial agent that could be used to combat microorganisms responsible for waterborne illnesses.

Total Phenolic Compound and Antimicrobial Activity of Spirogyra spp.

Spirogyra spp. is widely distributed in freshwater habitats and is included in the category of natural resources whose significance and advantages have been researched. In this study, 6 samples of Spirogyra spp. were collected: Spirogyra ellipsospora Transeua from Bueng Kan province, Spirogyra sp.1 from Sakon Nakhon Province and S. neglecta (Hassall) Kützing, S. ellipsospora Transeua, Spirogyra sp.2, and Spirogyra sp.3 from Nakhon Phanom province. The highest value of total phenolic compound was measured at 18.53±0.23 mg GAE/mg in Spirogyra sp. 2. The evaluation of antimicrobial activity of algal extracts against fungal Candida sp. and bacteria Staphylococcus aureus and Escherichia coli was performed by using the disk diffusion method along with determination of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum bacterial concentration (MBC). The result of disk diffusion and MIC determination showed the efficiency of all extract samples against all tested strains at a concentration of 10 mg/mL. The most effective algal extract against Candida sp. showed with the MFC’s ranged from 10 to 20 mg/mL, whereas MBC of all extracts destroyed the two tested bacterial strains ranged from 10 to 20 mg/mL within 24 hours and up to 30 mg/mL after 48 hours. The results of this study support that Spirogyra spp. contains bioactive compounds that are the basis for further application in cosmeceuticals.

Antimicrobial Activity and Phytochemical Composition of Allium sativum Bulb Extracts against Selected Gram-Negative Bacteria

As a result of increasing antibiotics resistance due to multidrug resistance leads to the use of the medicinal plants as alternative antimicrobial agents. The study aimed to investigate the antimicrobial and phytochemical properties of Allium sativum bulb extracts against some selected gram-negative bacteria isolates. Allium sativum oil was extracted using Soxhlet extraction procedures; Clinical bacterial isolates were collected from pathology department of General Hospital Potiskum in Yobe state. Isolates were identified using standard methods. Antibacterial activity of different concentrations (20, 40, 60, 80 and 100) % of oil extract of Allium sativum bulb were investigated against five clinical bacterial isolates including, Proteus vulgaris, Pseudomonas aeruginosa, Escherichia coli, Shigella boydii and Klebsiella oxytoca.. The oil extract of the bulbs showed antimicrobial activity against all five clinical isolates. MICs and MBCs were evaluated by broth dilution method. The minimum inhibitory concentration (MIC) values for all the three oil extracts ranged between 0.5 and 1.0%, while the minimum bacterial concentration (MBC) values ranged between 1.0 and 1.5%. Important bioactive constituents were present in the different oil extraction method; alkaloids (for ethanol extracts, 19.04±0.04, for hexane extracts, 20.04±0.14 and for chloroform extracts, 20.04±0.07) and 0.51±0.01were detected for sterols in all the three oil extraction methods while others such as flavonoids, saponins, tannins and phenols were not detected. The yield extracts of the oil extract of the bulbs, for hexane were 12.6%, chloroform, 15.2% and ethanol, 16.2%, indicating that ethanol was the better of the three solvents used. The potential applications of Allium sativum oil extracts as natural antimicrobial agents call for the importance of further investigation into their nutritional potential.

Trans-cinnamaldehyde fumigation inhibits Escherichia coli by affecting the mechanism of intracellular biological macromolecules

This study aimed to determine the antibacterial mechanism of cinnamaldehyde fumigation in Escherichia coli (E. coli). Through vapour fumigation, cinnamaldehyde was confirmed to exhibit effective antibacterial activity against E. coli. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) were 0.25 μL/mL and 0.5 μL/mL, respectively. Based on transmission electron microscopy, the wrinkled bacterial cells observed after fumigation could be related to the leakage of intracellular substances. Laser tweezers Raman spectroscopy revealed changes in the main chain of proteins, the hydrogen bond system and spatial structure, and single- and double-stranded DNA breaks. In addition, breakage of the fatty acyl chain backbone was found to affect the vertical order degree of the lipid bilayer and cell membrane fluidity, thereby inhibiting the growth of E. coli. Overall, our findings indicate that cinnamaldehyde fumigation inhibits E. coli growth by inducing changes in intracellular biological macromolecules.

Preparation of biguanidine quaternary ammonium salts grafted chitosan with enhanced antibacterial and antibiofilm activities

N-(4-N′-pyridine-benzylcarbonyl chloride) chitosan (CBPyC), N-p-biguanidine benzoyl chitosan (CSBG), and N-(p-biguanidine -1-pyridine-4-benzylcarbonyl chloride) chitosan (CSQPG) were synthesized. The structures of prepared chitosan derivatives were characterized using nuclear magnetic resonance spectroscopy (NMR) and ultraviolet–visible (UV–vis) spectroscopy, and the degree of substitution was determined through elemental analysis (EA) and evaluated on the basis of the integral values in 1H NMR. The antibacterial activities of chitosan derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated in vitro using antibacterial rate, minimal inhibitory concentration and minimum bacterial concentration assays. The antibiofilm activity was also assessed using the crystal violet assay. CSQPC exhibited higher antibacterial and antibiofilm activities against E. coli and S. aureus compared to CBPyC and CSBG.The antibacterial rate of CSQPG against E. coli and S. aureus at a concentration of 0.5 mg/mL was 43.3% and 100%, respectively. The biofilm inhibition rate of CSQPG at 0.5 MIC against E. coli and S. aureus was 56.5% and 69.1%, respectively. At a concentration of 2.5 mg/mL, the biofilm removal rates of E. coli and S. aureus were 72.9% and 90.1%, respectively. The antibacterial and antibiofilm activities of CSQPG were better than CSBG and CBPyC, and the combination of guanidine and quaternary ammonium further improved the positive charge density of chitosan and enhanced its antibacterial activity.

Antibody functionalized capacitance sensor for label-free and real-time detection of bacteria and antibiotic susceptibility

The effective management of infectious diseases and the growing concern of antibiotic resistance necessitates accurate and targeted therapies, highlighting the importance of antibiotic susceptibility testing. This study aimed to develop a real-time impedimetric biosensor for identifying and monitoring bacterial growth and antibiotic susceptibility. The biosensor employed a gold 8-channel disk-shaped microelectrode array with specific antibodies as bio-recognition elements. This setup was allowed for the analysis of bacterial samples, including Staphylococcus aureus, Bacillus cereus, and Micrococcus luteus. These microorganisms were successfully cultured and detected within 1 h of incubation even with a minimal bacterial concentration of 10 CFU/ml. Overall, the developed biosensor array exhibits promising capabilities for monitoring S. aureus, B. cereus and M. luteus, showcasing an excellent linear response ranging from 10 to 104 CFU/ml with a detection limit of 0.95, 1.22 and 1.04 CFU/mL respectively. Moreover, real-time monitoring of antibiotic susceptibility was facilitated by changes in capacitance, which dropped when bacteria were exposed to antibiotic doses higher than their minimum inhibitory concentration (MIC), indicating suppressed bacterial growth. The capacitance measurements enabled determination of half-maximal cytotoxic concentrations (CC50) values for each bacteria-antibiotic pair. As a proof-of-concept application, the developed sensor array was employed as a sensing platform for the real time detection of bacteria in milk samples, which ensured the reliability of the sensor for in-field detection of foodborne pathogens and rapid antimicrobial susceptibility tests (ASTs).

Effect of zinc nanoparticles on the mechanical properties and stability of the resin-dentin bonded interface

To evaluate the effect of zinc oxide and zinc fluoride nanoparticle solution (ZNS) as pretreatment on the mechanical properties and stability of resin-dentin bonded interface. Pretreatment solutions were applied after phosphoric acid: 5 and 10% Zinc Oxide (ZO5; ZO10); 1.5 and 3% Zinc Fluoride (ZF1.5 and ZF3); 0.2% chlorhexidine (CHX-positive control) and no pretreatment (NC-negative control). The treated teeth were restored and stored for 24 h and 12 m prior to microtensile bond strength (µTBS) testing (n = 8). Failure mode, nanohardness (NH) and young’s modulus (YM) (n = 3) were also evaluated. In situ zymography (n = 3) and interface morphology (n = 3) were evaluated after 24 h. The antibacterial activity was determined by minimum inhibitory (MIC) and bacterial (MBC) concentration. The µTBS was evaluated by two-way mixed ANOVA and NH and YM data were analyzed by two-way mixed repeated-measures ANOVA (α = 0.05). In situ zymography, interface morphology, MIC and MBC were descriptively analyzed. The µTBS of ZF3, ZO10 and CHX was maintained over time, while for ZF1.5 and Z05 it was increased. Mixed failures were the most prevalent for all groups. ZF3 presented higher values of NH and YM with incorporation of nanoparticles being observed within the hybrid layer on the interface morphology image. CHX presented the lowest enzymatic activity followed by ZO5. MIC and MBC for ZO were 62.5 µg/mL and ZF 3.25 µg/mL, respectively. Pretreatment with ZNS, specially zinc fluoride, seems to be a promising method to increase the longevity of restorations.

In Vitro Antibacterial Activity of a Novel Acid-Activated Antimicrobial Peptide against Streptococcus mutans.

Dental caries is an oral disease associated with infection by microbial biofilm. The metabolic activity of cariogenic bacteria results in a pH decrease in the plaque biofilm, causing tooth demineralization. This acidic environment favors the growth of cariogenic bacteria that are highly resistant to strong acids, which, in turn, produce more acid resulting in a further decrease in the pH of the plaque biofilm. Therefore, the strategy of utilizing the acidic dental plaque microenvironment to prevent and treat dental caries has become a hot research topic in recent years, such as the development of pH-sensitive drug delivery systems. Design of a new acid-activated antibacterial peptide. To design and synthesis an acid targeted antimicrobial peptide with the GWHHFFHFFHFF sequence. Minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) testing confirmed its antibacterial activity. Propidium iodide (PI) staining was used to detect nucleic acid leakage. Determination of anti-biofilm activity by biofilm inhibition assay. A phototoxicity study confirmed the phototoxicity of PPIX-P12. MIC and MBC testing confirmed that P12 possessed acid-activated anti-Streptococcus mutans activity. Bactericidal kinetic experiments and propidium iodide (PI) staining experiments showed that P12 killed planktonic S. mutans UA159 cells leading to the leakage of nucleic acids in the acidic medium. Moreover, P12 showed acid-activated anti-biofilms at the early and mature biofilm stages. P12 was conjugated with the phototherapeutic agent protoporphyrin IX (PpIX) to construct the protoporphyrin derivative PpIX-P12. In vitro experiments revealed that PpIX-P12 displayed better antibacterial activity in pH 5.5 medium than in pH 7.2 medium. In conclusion, we designed an acid-activated AMP, which had no antimicrobial activity at neutral pH, but had antimicrobial activity at an acidic pH.

Antimicrobial, Nutritional and Bioactive Properties of Cola Lepidota &Cola Pachycarpa (Ochicha) Seed Extracts on Three Strains of Organisms.

This study evaluated the phytochemical composition, antioxidant activity, and antimicrobial potentials of Cola lepidota and Cola pachycarpa seeds. Ethanol and distilled water were used as solvents for phytochemical extraction, while the test bacterial strains were obtained from the National Veterinary Research Institute, Vom, Jos, Plateau State. The plant bioactive compounds were detected using qualitative and quantitative phytochemical evaluation, including gas chromatography-mass spectrometry (GC/MS) analytical methods. Proximate composition was determined, and antioxidant activity was assessed using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH), reducing power activity, and ABTS+ assays. The antibacterial activity of the seed extract was evaluated via the minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) using the agar-well diffusion method. The result of quantitative analysis showed lower concentrations of phenols (1.26 mg/g and 1.35 mg/g), flavonoids (0.87 mg/g and 0.93 mg/g), tannins (1.08 mg/g and 1.17 mg/g), saponins (1.49 mg/g and 1.57 mg/g), and alkaloids (0.43 mg/g and 0.46 mg/g) in C. lepidota than in C. pachycarpa. Conversely, the mineral composition was higher in C. lepidota, recording 3.92%, 1.02%, 0.17%, 0.02%, and 0.01% for potassium, phosphorus, calcium, sodium, and iron, respectively. The extracts showed no inhibitory activity against the bacterial strains: Escherichia coli ATCC 0157, Staphylococcus aureus ATCC 6538, and Bacillus substilis ATCC 6633. As such, failed to justify the ethno-pharmaceutical uses in the treatment of bacterial diseases. However, they demonstrated rich innate antioxidant activity and may be helpful in the prevention or reduction of oxidation or similar associated disorders in humans.

Nutritional and Bioactive Properties of Cola Lepidota & Cola Pachycarpa (Ochicha) Seed Extracts on Three Strains of Organisms

This study evaluated the phytochemical composition, antioxidant activity, and antimicrobial potentials of Cola lepidota and Cola pachycarpa seeds. Ethanol and distilled water were used as solvents for phytochemical extraction, while the test bacterial strains were obtained from the National Veterinary Research Institute, Vom, Jos, Plateau State. The plant bioactive compounds were detected using qualitative and quantitative phytochemical evaluation, including gas chromatography-mass spectrometry (GC/MS) analytical methods. Proximate composition was determined, and antioxidant activity was assessed using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH), reducing power activity, and ABTS+ assays. The antibacterial activity of the seed extract was evaluated via the minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) using the agar-well diffusion method. The result of quantitative analysis showed lower concentrations of phenols (1.26 mg/g and 1.35 mg/g), flavonoids (0.87 mg/g and 0.93 mg/g), tannins (1.08 mg/g and 1.17 mg/g), saponins (1.49 mg/g and 1.57 mg/g), and alkaloids (0.43 mg/g and 0.46 mg/g) in C. lepidota than in C. pachycarpa. Conversely, the mineral composition was higher in C. lepidota, recording 3.92%, 1.02%, 0.17%, 0.02%, and 0.01% for potassium, phosphorus, calcium, sodium, and iron, respectively. The extracts showed no inhibitory activity against the bacterial strains: Escherichia coli ATCC 0157, Staphylococcus aureus ATCC 6538, and Bacillus substilis ATCC 6633. As such, failed to justify the ethno-pharmaceutical uses in the treatment of bacterial diseases. However, they demonstrated rich innate antioxidant activity and may be helpful in the prevention or reduction of oxidation or similar associated disorders in humans.