A new fabricated hetero-atom doped carbon quantum dots as a fluorescent probe for metronidazole determination using garlic and red lentils with microwave assistance.

Biocompatible and highly fluorescent phosphorus, nitrogen and sulfur carbon quantum dots (P,N,S-CQDs) were synthesized using a quick and ecologically friendly process inspired from plant sources. Garlic and red lentils were utilized as natural and inexpensive sources for efficient synthesis of the carbon-based quantum dots using green microwave-irradiation, which provides an ultrafast route for carbonization of the organic biomass and subsequent fabrication of P,N,S-CQDs within only 3 min. The formed P,N,S-CQDs showed excellent blue fluorescence at λem = 412 nm when excited at 325 nm with a quantum yield up to 26.4%. These fluorescent dots were used as a nano-sensor for the determination of the commonly used antibacterial and antiprotozoal drug, metronidazole (MTR). As MTR lacked native fluorescence and prior published techniques had several limitations, the proposed methodology became increasingly relevant. This approach affords sensitive detection with a wide linear range of 0.5-100.0 µM and LOD and LOQ values of 0.14 µM and 0.42 µM, respectively. As well as, it is cost-effective and ecologically benign. The MTT test was used to evaluate the in-vitro cytotoxicity of the fabricated P,N,S-CQDs. The findings supported a minimally cytotoxic impact and good biocompatibility, which provide a future perspective for the applicability of these CQDs in biomedical applications.

Anti-quorum sensing activity of α-amidoamides against Agrobacterium tumefaciensNT1: Insights from molecular docking and dynamic investigations to synergistic approach of metronidazole release from gel formulations.

A unique approach is imperative for the development of drugs aimed at inhibiting various stages of infection, rather than solely focusing on bacterial viability. Among the array of unconventional targets explored for formulating novel antimicrobial medications, blocking the quorum-sensing (QS) system emerges as a highly effective and promising strategy against a variety of pathogenic microbes. In this investigation, we have successfully assessed nine α-aminoamides for their anti-QS activity using Agrobacterium tumefaciensNT1 as a biosensor strain. Among these compounds, three (2, 3and, 4) have been identified as potential anti-QS candidates. Molecular docking studies have further reinforced these findings, indicating that these compounds exhibit favorable pharmacokinetic profiles. Additionally, we have assessed the ligand's stability within the protein's binding pocket using molecular dynamics (MD) simulations and MMGBSA analysis. Further, combination of antiquorum sensing properties with antibiotics viaself-assembly represents a promising approach to enhance antibacterial efficacy, overcome resistance, and mitigate the virulence of bacterial pathogens. The release study also reflects a slow and gradual release of the metronidazole at both pH 6.5 and pH 7.4, avoiding the peaks and troughs associated with more immediate release formulations.

[Porphyromonas gingivalis persisters induce the immuno-inflammatory responses in macrophages by upregulating the forkhead box1 signaling pathway].

Objective: To investigate the effects of Porphyromonas gingivalis (Pg) persisters (Ps) on immuno-inflammatory responses in macrophages, and to explore the underlying mechanisms. Methods: Pg cells were cultured to the stationary phase (72 h), and subsequently treated by high concentration of metronidazole at 100 mg/L, amoxicillin at 100 mg/L and the combination of them for different time period, named as metronidazole group, amoxicillin group and (metronidazole+amoxicillin) group. Pg cells without treatment were used as Blank control. The survival profile of PgPs cells was measured by colony-forming unit assay. The living state of PgPs was observed by Live/Dead staining. Then, Pg and metronidazole-treated PgPs (M-PgPs) were used to treat macrophages, named as Pg group and M-PgPs group. Transmission electron microscopy (TEM) was used to observe the bacteria in the macrophages. The expression levels of proinflammatory cytokines in macrophages were determined by real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay. The location of forkhead box transcription factor 1 (FOXO1) was detected by confocal immunofluorescence microscopy. After inhibiting or enhancing the FOXO1 expressions using inhibitors (Fi) or activators (Fa) respectively, the macrophages were treated with Pg and M-PgPs, divided as Blank group, Pg group, M-PgPs group, Fi group, (Fi+Pg) group, (Fi+M-PgPs) group, Fa group, (Fa+Pg) group and (Fa+M-PgPs) group. Then, the expression pattens of proinflammatory cytokines were assessed. Results: Remarkable number of lived PgPs was observed, both in planktonic culture and Pg biofilms either treated with metronidazole, amoxicillin or both, and those persisters could form new colonies. Pg and M-PgPs were able to enter into the macrophages and the protein expression levels of interleukin (IL)-1ß, IL-6, IL-8 and tumor necrosis factor-α (TNF-α) [Pg group: (2 392±188), (162±29), (5 558±661), (789±155) µg/L; M-PgPs group: (2 415±420), (155±3), (5 732±782), (821±176) µg/L] were significantly upregulated than those in Blank group [(485±140), (21±9), (2 332±87), (77±7) µg/L] (P<0.01). Moreover, Pg and M-PgPs could facilitate the nuclear translocation and accumulation of FOXO1. In addition, the relative mRNA expression levels of FOXO1, B-cell lymphoma 6 and Krüppel-like factor 2 were upregulated when compared to Blank group (P<0.05). Furthermore, the protein expression levels of IL-1ß, IL-6, IL-8 and TNF-α in Fi+Pg group [(1 081±168), (70±8), (1 976±544), (420±47) µg/L] were remarkably lower than Pg group [(4 411±137), (179±6), (5 161±929), (934±24) µg/L] (P<0.05). Similarly, the protein expression levels of IL-1ß, IL-6, IL-8 and TNF-α in Fi+M-PgPs group [(1 032±237), (74±10), (1 861±614), (405±32) µg/L] were remarkably lower than M-PgPs group [(4 342±314), (164±17), (4 438±1 374), (957±25) µg/L] (P<0.05). On the contrary, the protein expression levels of IL-1ß, IL-6, IL-8 and TNF-α in Fa+Pg group [(8 198±1 825), (431±28), (8 919±650), (2 186±301) µg/L] and Fa+M-PgPs group [(8 159±2 627), (475±26), (8 995±653), (2 255±387) µg/L] were significantly higher than Pg group and M-PgPs group, respectively (P<0.05). Conclusions: PgPs are highly tolerant to metronidazole and amoxicillin. The M-PgPs could enhance the immuno-inflammatory responses in macrophages by upregulating the FOXO1 signaling pathway, while this effect exhibits no significant difference with Pg.

Investigation of the Antitrichomonal Activity of Cinnamaldehyde, Carvacrol and Thymol and Synergy with Metronidazole.

Objective: Trichomonas vaginalis is a sexually transmitted protozoan parasite that usually causes infections in women. Metronidazole is used as the first choice in the treatment of this parasitic disease, but there is a need for new drugs since 1980's with increasing numbers of reported resistance. In this study, it was aimed to determine the antitrichomonal activity of the major components of Cinnamomum zeylanicum (cinnamon) and Thymus vulgaris (thyme) essential oils, cinnamaldehyde, carvacrol and thymol against metronidazole resistant and susceptible T. vaginalis strains, and to determine their interaction with metronidazole by checkerboard method. Methods: Cinnamaldehyde, carvacrol, thymol and metronidazole were obtained commercially. Two clinical isolates and one metronidazole resistant T. vaginalis reference strain were used in the study. MIC50 and MLC values of essential oil components and metronidazole were determined by broth microdilution method. The combinations of essential oil components with metronidazole were determined by the checkerboard method. Results: According to in vitro activity tests, cinnamaldehyde was determined to be most effective essential oil component. Clinical isolates were susceptible to metronidazole. In combination study, metronidazole showed synergy with cinnamaldehyde and carvacrol, and partial synergy with thymol. Conclusion: It was determined that cinnamaldehyde, carvacrol and thymol, which are known to have high antimicrobial activity, also have strong activity against T. vaginalis isolates and show a synergistic interaction with metronidazole. The use of metronidazole at lower doses in the synergistic interaction may contribute to the literature in terms of reducing drug side effects, creating a versatile antimicrobial target, and reducing the rate of resistance development.

Imidazole Carbamates as a Promising Alternative for Treating Trichomoniasis: In Vitro Effects on the Growth and Gene Expression of Trichomonas vaginalis.

Metronidazole (MTZ) is the most common drug used against Trichomonas vaginalis (T. vaginalis) infections; however, treatment failures and high rates of recurrence of trichomoniasis have been reported, suggesting the presence of resistance in T. vaginalis to MTZ. Therefore, research into new therapeutic options against T. vaginalis infections has become increasingly urgent. This study investigated the trichomonacidal activity of a series of five imidazole carbamate compounds (AGR-1, AGR-2, AGR-3, AGR-4, and AGR-5) through in vitro susceptibility assays to determine the IC50 value of each compound. All five compounds demonstrated potent trichomonacidal activity, with IC50 values in the nanomolar range and AGR-2 being the most potent (IC50 400 nM). To gain insight into molecular events related to AGR-induced cell death in T. vaginalis, we analyzed the expression profiles of some metabolic genes in the trophozoites exposed to AGR compounds and MTZ. It was found that both AGR and MTZ compounds reduced the expression of the glycolytic genes (CK, PFK, TPI, and ENOL) and genes involved in metabolism (G6PD, TKT, TALDO, NADHOX, ACT, and TUB), suggesting that disturbing these key metabolic genes alters the survival of the T. vaginalis parasite and that they probably share a similar mechanism of action. Additionally, the compounds showed low cytotoxicity in the Caco-2 and HT29 cell lines, and the results of the ADMET analysis indicated that these compounds have pharmacokinetic properties similar to those of MTZ. The findings offer significant insights that can serve as a basis for future in vivo studies of the compounds as a potential new treatment against T. vaginalis.

Nano-sensitizer with self-amplified drug release and hypoxia normalization properties potentiates efficient chemoradiotherapy of pancreatic cancer.

The hypoxic nature of pancreatic cancer, one of the most lethal malignancies worldwide, significantly impedes the effectiveness of chemoradiotherapy. Although the development of oxygen carriers and hypoxic sensitizers has shown promise in overcoming tumor hypoxia. The heterogeneity of hypoxia-primarily caused by limited oxygen penetration-has posed challenges. In this study, we designed a hypoxia-responsive nano-sensitizer by co-loading tirapazamine (TPZ), KP372-1, and MK-2206 in a metronidazole-modified polymeric vesicle. This nano-sensitizer relies on efficient endogenous NAD(P)H quinone oxidoreductase 1-mediated redox cycling induced by KP372-1, continuously consuming periphery oxygen and achieving evenly distributed hypoxia. Consequently, the normalized tumor microenvironment facilitates the self-amplified release and activation of TPZ without requiring deep penetration. The activated TPZ and metronidazole further sensitize radiotherapy, significantly reducing the radiation dose needed for extensive cell damage. Additionally, the coloaded MK-2206 complements inhibition of therapeutic resistance caused by Akt activation, synergistically enhancing the hypoxic chemoradiotherapy. This successful hypoxia normalization strategy not only overcomes hypoxia resistance in pancreatic cancer but also provides a potential universal approach to sensitize hypoxic tumor chemoradiotherapy by reshaping the hypoxic distribution.

Green synthesis of nanohydroxyapatite with Elaeagnus angustifolia L. extract as a metronidazole nanocarrier for in vitro pulpitis model treatment.

The aim of this study is to introduce a dental capping agent for the treatment of pulp inflammation (pulpitis). Nanohydroxyapatite with Elaeagnus angustifolia L. extract (nHAEA) loaded with metronidazole (nHAEA@MTZ) was synthesized and evaluated using a lipopolysaccharide (LPS) in vitro model of pulpitis. nHAEA was synthesized through sol-gel method and analyzed using Scanning Electron Microscopy, Transmission Electron Microscopy, and Brunauer Emmett Teller. Inflammation in human dental pulp stem cells (HDPSCs) induced by LPS. A scratch test assessed cell migration, RT PCR measured cytokines levels, and Alizarin red staining quantified odontogenesis. The nHAEA nanorods were 17-23 nm wide and 93-146 nm length, with an average pore diameter of 27/312 nm, and a surface area of 210.89 m2/g. MTZ loading content with controlled release, suggesting suitability for therapeutic applications. nHAEA@MTZ did not affect the odontogenic abilities of HDPSCs more than nHAEA. However, it was observed that nHAEA@MTZ demonstrated a more pronounced anti-inflammatory effect. HDPSCs treated with nanoparticles exhibited improved migration compared to other groups. These findings demonstrated that nHAEA@MTZ could be an effective material for pulp capping and may be more effective than nHAEA in reducing inflammation and activating HDPSCs to enhance pulp repair after pulp damage.

Small molecule MarR modulators potentiate metronidazole antibiotic activity in aerobic E. coli by inducing activation by the nitroreductase NfsA.

Antibiotic-resistant Enterobacterales pose a major threat to healthcare systems worldwide, necessitating the development of novel strategies to fight such hard-to-kill bacteria. One potential approach is to develop molecules that force bacteria to hyper-activate prodrug antibiotics, thus rendering them more effective. In the present work, we aimed to obtain proof-of-concept data to support that small molecules targeting transcriptional regulators can potentiate the antibiotic activity of the prodrug metronidazole (MTZ) against Escherichia coli under aerobic conditions. By screening a chemical library of small molecules, a series of structurally related molecules were identified that had little inherent antibiotic activity but showed substantial activity in combination with ineffective concentrations of MTZ. Transcriptome analyses, functional genetics, thermal shift assays, and electrophoretic mobility shift assays were then used to demonstrate that these MTZ boosters target the transcriptional repressor MarR, resulting in the upregulation of the marRAB operon and its downstream MarA regulon. The associated upregulation of the flavin-containing nitroreductase, NfsA, was then shown to be critical for the booster-mediated potentiation of MTZ antibiotic activity. Transcriptomic studies, biochemical assays, and electron paramagnetic resonance measurements were then used to show that under aerobic conditions, NfsA catalyzed 1-electron reduction of MTZ to the MTZ radical anion which in turn induced lethal DNA damage in E. coli. This work reports the first example of prodrug boosting in Enterobacterales by transcriptional modulators and highlights that MTZ antibiotic activity can be chemically induced under anaerobic growth conditions.

Structural Evaluation of a Nitroreductase Engineered for Improved Activation of the 5-Nitroimidazole PET Probe SN33623.

Bacterial nitroreductase enzymes capable of activating imaging probes and prodrugs are valuable tools for gene-directed enzyme prodrug therapies and targeted cell ablation models. We recently engineered a nitroreductase (E. coli NfsB F70A/F108Y) for the substantially enhanced reduction of the 5-nitroimidazole PET-capable probe, SN33623, which permits the theranostic imaging of vectors labeled with oxygen-insensitive bacterial nitroreductases. This mutant enzyme also shows improved activation of the DNA-alkylation prodrugs CB1954 and metronidazole. To elucidate the mechanism behind these enhancements, we resolved the crystal structure of the mutant enzyme to 1.98 Å and compared it to the wild-type enzyme. Structural analysis revealed an expanded substrate access channel and new hydrogen bonding interactions. Additionally, computational modeling of SN33623, CB1954, and metronidazole binding in the active sites of both the mutant and wild-type enzymes revealed key differences in substrate orientations and interactions, with improvements in activity being mirrored by reduced distances between the N5-H of isoalloxazine and the substrate nitro group oxygen in the mutant models. These findings deepen our understanding of nitroreductase substrate specificity and catalytic mechanisms and have potential implications for developing more effective theranostic imaging strategies in cancer treatment.

Il34 rescues metronidazole-induced impairment of spinal cord regeneration in zebrafish central nervous system.

Metronidazole (MTZ), a commonly used anti-infective drug in clinical practice, has also been employed as a prodrug in cell-targeted ablation systems in scientific research, exhibiting significant application value. However, it has been demonstrated that MTZ can induce neurotoxic symptoms to some extent during its use, and there is currently a lack of effective means to circumvent its toxicity in both clinical and research settings, which limits its application. Therefore, exploring the specific mechanisms underlying MTZ-induced neurotoxic symptoms and elucidating countermeasures will enhance the practical value of MTZ. In this study, using a zebrafish spinal cord injury regeneration model, we confirmed that MTZ neurotoxicity leads to impaired axon regeneration in the central nervous system. By overexpressing il34 in the central nervous system of zebrafish, we eliminated the inhibitory effect of MTZ on axonal regeneration and demonstrated that the pro-regenerative effect against MTZ neurotoxicity is not caused by excessive macrophages/microglia chemoattracted by interleukin 34(Il34). Transcriptome sequencing analysis and GO enrichment analysis of differentially expressed genes between groups revealed that Il34 may counteract MTZ neurotoxicity and promote spinal cord injury repair through biological processes that enhance cellular adhesion and cell location. In summary, our work uncovers a possible cause of MTZ neurotoxicity and provides a new perspective for eliminating MTZ toxicity.

Prevalence of Helicobacter pylori resistance to certain antibiotics at An-Najah University Hospital: a cross-sectional study.

Antibiotic resistance among bacteria is recognized as the primary factor contributing to the failure of treatment. In this research, our objective was to examine the prevalence of antibiotic resistance in H. pylori bacteria in Palestine. We enlisted 91 individuals suffering from dyspepsia, comprising 49 females and 42 males. These participants underwent esophagogastroduodenoscopy procedures with gastric biopsies. These biopsies were subsequently subjected to microbiological assessments and tested for their susceptibility to various antimicrobial drugs. Among the 91 patients, 38 (41.7%) exhibited the presence of H. pylori. Notably, Ciprofloxacin displayed the highest efficacy against H. pylori, followed by Levofloxacin, Moxifloxacin, and Amoxicillin, with resistance rates of 0%, 0%, 2.6%, and 18.4%, respectively. On the contrary, Metronidazole and Clarithromycin demonstrated the lowest effectiveness, with resistance percentages of 100% and 47.4%, respectively. The outcomes of this investigation emphasize that H. pylori strains within the Palestinian patient group exhibit substantial resistance to conventional first-line antibiotics like clarithromycin and metronidazole. However, alternative agents such as fluoroquinolones and amoxicillin remain efficacious choices. Consequently, we recommend favoring quinolone-based treatment regimens for H. pylori infections and adopting a more judicious approach to antibiotic usage among the Palestinian population.

Exclusion of sulfide:quinone oxidoreductase from mitochondria causes Leigh-like disease in mice by impairing sulfide metabolism.

Leigh syndrome is the most common inherited mitochondrial disease in children and is often fatal within the first few years of life. In 2020, mutations in the gene encoding sulfide:quinone oxidoreductase (SQOR), a mitochondrial protein, were identified as a cause of Leigh syndrome. Here, we report that mice with a mutation in the gene encoding SQOR (SqorΔN/ΔN mice), which prevented SQOR from entering mitochondria, had clinical and pathological manifestations of Leigh syndrome. SqorΔN/ΔN mice had increased blood lactate levels that were associated with markedly decreased complex IV activity and increased hydrogen sulfide (H2S) levels. Because H2S is produced by both gut microbiota and host tissue, we tested whether metronidazole (a broad-spectrum antibiotic) or a sulfur-restricted diet rescues SqorΔN/ΔN mice from developing Leigh syndrome. Daily treatment with metronidazole alleviated increased H2S levels, normalized complex IV activity and blood lactate levels, and prolonged the survival of SqorΔN/ΔN mice. Similarly, a sulfur-restricted diet normalized blood lactate levels and inhibited the development of Leigh syndrome. Taken together, these observations suggest that mitochondrial SQOR is essential to prevent systemic accumulation of H2S. Metronidazole administration and a sulfur-restricted diet may be therapeutic approaches to treatment of patients with Leigh syndrome caused by mutations in SQOR.

Evidence of Helicobacter pylori heterogeneity in human stomachs by susceptibility testing and characterization of mutations in drug-resistant isolates.

Heterogeneity of Helicobacter pylori communities contributes to its pathogenicity and diverse clinical outcomes. We conducted drug-susceptibility tests using four antibiotics, clarithromycin (CLR), amoxicillin (AMX), metronidazole and sitafloxacin, to examine H. pylori population diversity. We also analyzed genes associated with resistance to CLR and AMX. We examined multiple isolates from 42 Japanese patients, including 28 patients in whom primary eradication with CLR and AMX had failed, and 14 treatment-naïve patients. We identified some patients with coexistence of drug resistant- and sensitive-isolates (drug-heteroR/S-patients). More than 60% of patients were drug-heteroR/S to all four drugs, indicating extensive heterogeneity. For the four drugs except AMX, the rates of drug-heteroR/S-patients were higher in treatment-naïve patients than in primary eradication-failure patients. In primary eradication-failure patients, isolates multi-resistant to all four drugs existed among other isolates. In primary eradication-failure drug-heteroR/S-patients, CLR- and AMX-resistant isolates were preferentially distributed to the corpus and antrum with different minimum inhibitory concentrations, respectively. We found two mutations in PBP1A, G591K and A480V, and analyzed these in recombinants to directly demonstrate their association with AMX resistance. Assessment of multiple isolates from different stomach regions will improve accurate assessment of H. pylori colonization status in the stomach.

Antibiotic resistance and virulence genes in Helicobacter pylori strains isolated from children in Shanghai, China (2019-2022).

BACKGROUND: The increasing prevalence of antibiotic-resistant Helicobacter pylori strains poses a significant threat to children's health. This study investigated antibiotic resistance rates in Helicobacter pylori strains isolated from children in Shanghai and analyzed the presence of virulence genes in these strains. METHODS: We obtained 201 Helicobacter pylori strains from pediatric patients with upper gastrointestinal symptoms who underwent gastrointestinal endoscopy between 2019 and 2022. Subsequently, we performed antibiotic susceptibility tests and virulence gene PCR assays on these strains. RESULTS: Helicobacter pylori resistance rates of 45.8%, 15.4%, 1.0%, and 2.5% were detected for metronidazole, clarithromycin, amoxicillin, and levofloxacin, respectively. Among all isolates, 64.7% exhibited resistance to at least one antibiotic. Resistance to metronidazole and clarithromycin increased from 2019 to 2022. The predominant vacA gene subtype was vacA s1a/m2. The prevalence of vacA m2 and dupA exhibited an upward trend, while oipA presented a decreasing trend from 2019 to 2022. The prevalence of dupA was significantly higher in gastritis than peptic ulcer disease, and in non-treatment compared to treatment groups. CONCLUSIONS: Helicobacter pylori antibiotic resistance remains high in children and has risen in recent years. Therefore, the increasing use of metronidazole and clarithromycin requires increased monitoring in children. No association was observed between antibiotic resistance and virulence gene phenotypes.

Silver Complexes of Miconazole and Metronidazole: Potential Candidates for Melanoma Treatment.

Melanoma, arguably the deadliest form of skin cancer, is responsible for the majority of skin-cancer-related fatalities. Innovative strategies concentrate on new therapies that avoid the undesirable effects of pharmacological or medical treatment. This article discusses the chemical structures of [(MTZ)2AgNO3], [(MTZ)2Ag]2SO4, [Ag(MCZ)2NO3], [Ag(MCZ)2BF4], [Ag(MCZ)2SbF6] and [Ag(MCZ)2ClO4] (MTZ-metronidazole; MCZ-miconazole) silver(I) compounds and the possible relationship between the molecules and their cytostatic activity against melanoma cells. Molecular Hirshfeld surface analysis and computational methods were used to examine the possible association between the structure and anticancer activity of the silver(I) complexes and compare the cytotoxicity of the silver(I) complexes of metronidazole and miconazole with that of silver(I) nitrate, cisplatin, metronidazole and miconazole complexes against A375 and BJ cells. Additionally, these preliminary biological studies found the greatest IC50 values against the A375 line were demonstrated by [Ag(MCZ)2NO3] and [(MTZ)2AgNO3]. The compound [(MTZ)2AgNO3] was three-fold more toxic to the A375 cells than the reference (cisplatin) and 15 times more cytotoxic against the A375 cells than the normal BJ cells. Complexes of metronidazole with Ag(I) are considered biocompatible at a concentration below 50 µmol/L.

15N Hyperpolarization of Metronidazole Antibiotic in Aqueous Media Using Phase-Separated Signal Amplification by Reversible Exchange with Parahydrogen.

Metronidazole is a prospective hyperpolarized MRI contrast agent with potential hypoxia sensing utility for applications in cancer, stroke, neurodegenerative diseases, etc. We demonstrate a pilot procedure for production of ∼30 mM hyperpolarized [15N3]metronidazole in aqueous media by using a phase-separated SABRE-SHEATH hyperpolarization method, with nitrogen-15 polarization exceeding 2.2% on all three 15N sites achieved in less than 2 min. The 15N polarization T1 of ∼12 min is reported for the 15NO2 group at the clinically relevant field of 1.4 T in the aqueous phase, demonstrating a remarkably long lifetime of the hyperpolarized state. The produced aqueous solution of [15N3]metronidazole that contained only ∼100 µM of residual Ir was deemed biocompatible via validation through the MTT colorimetric test for assessing cell metabolic activity using human embryotic kidney HEK293T cells. This low-cost and ultrafast hyperpolarization procedure represents a major advance for the production of a biocompatible HP [15N3]metronidazole (and potentially other hyperpolarized drugs) formulation for MRI sensing applications.

N-Hydroxyalkanamide Based Organo/hydrogels as Novel Scaffolds for pH-Dependent Metronidazole and Theophylline Release.

The traditional delivery of metronidazole and theophylline presents challenges like bitter taste, variable absorption, and side effects. However, gel-based systems offer advantages including enhanced targeted drug delivery, minimized side effects, and improved patient compliance, effectively addressing these challenges. Consequently, a cost-effective synthesis of N-hydroxyalkanamide gelators with varying alkyl chain lengths was achieved in a single-step reaction procedure. These gelators formed self-assembled aggregates in DMSO/water solvent system, resulting in organo/hydrogels at a minimum gelation concentration of 1.5 % w/v. Subsequently, metronidazole and theophylline were encapsulated within the gel core and released through gel-to-sol transition triggered by pH variation at 37 °C, while maintaining the structural-activity relationship. UV-vis spectroscopy was employed to observe the drug release behavior. Furthermore, in vitro cytotoxicity assays revealed cytotoxic effects against A549 lung adenocarcinoma cells, indicating anti-proliferative activity against human lung cancer cells. Specifically, the gel containing theophylline (16HAD+Th) exhibited cytotoxicity on cancerous A549 cells with IC50 values of 19.23±0.6 µg/mL, followed by the gel containing metronidazole (16HAD+Mz) with IC50 values of 23.75±0.7 µg/mL. Moreover, the system demonstrated comparable antibacterial activity against both gram-negative (E. coli) and gram-positive bacteria (S. aureus).

Specific delivery of metronidazole using microparticles and thermosensitive in situ hydrogel for intrapocket administration as an alternative in periodontitis treatment.

Periodontitis is a common chronic inflammatory disease primarily caused by the prevalence of bacterial overgrowth resulting in the development of an inflammatory condition that destroys the tooth's supporting tissues and eventual tooth loss. Comparatively, to other treatment methods, it is difficult for topical antibacterial drugs to effectively permeate the biofilm's physical barrier, making conventional therapy for periodontitis more challenging. This novel study combines thermosensitive in situ hydrogel with microparticles (MPs) to enhance the targeted delivery of metronidazole (MET) to the periodontal pocket. Polycaprolactone (PCL) polymer was utilized to produce bacteria-sensitive MPs. Additionally, the study assessed the attributes of MPs and demonstrated an enhancement in the in vitro antibacterial efficacy of MPs towards Staphylococcus aureus (SA) and Escherichia coli (EC). Subsequently, we incorporated MET-MPs into thermosensitive in situ hydrogel formulations using chitosan. The optimized formulations exhibited stability, appropriate gelation temperature, mucoadhesive strength, and viscosity. In vitro permeation tests showed selective and prolonged drug release against SA and EC. Ex vivo experiments demonstrated no significant differences between in situ hydrogel containing pure MET and MET-MPs in biofilm quantity, bacterial counts, and metabolic activity in biofilms. According to in vitro tests and the effectiveness of the antibacterial activity, this study has exhibited a novel methodology for more efficacious therapies for periodontitis. This study aims to utilize MET in MPs to improve its effectiveness, enhance its antibacterial activity, and improve patient treatment outcomes. In further research, the efficacy of the treatment should be investigated in vivo using an appropriate animal model.

Andrographolide induced cytotoxicity and cell cycle arrest in Giardia trophozoites.

Giardiasis is a prevalent parasitic diarrheal disease caused by Giardia lamblia, affecting people worldwide. Recently, the availability of several drugs for its treatment has highlighted issues such as multidrug resistance, limited effectiveness and undesirable side effects. Therefore, it is necessary to develop alternative new drugs and treatment strategies that can enhance therapeutic outcomes and effectively treat giardiasis. Natural compounds show promise in the search for more potent anti-giardial agents. Our investigation focused on the effect of Andrographolide (ADG), an active compound of the Andrographis paniculata plant, on Giardia lamblia, assessing trophozoite growth, morphological changes, cell cycle arrest, DNA damage and inhibition of gene expression associated with pathogenic factors. ADG demonstrated anti-Giardia activity almost equivalent to the reference drug metronidazole, with an IC50 value of 4.99 µM after 24 h of incubation. In cytotoxicity assessments and morphological examinations, it showed significant alterations in trophozoite shape and size and effectively hindered the adhesion of trophozoites. It also caused excessive ROS generation, DNA damage, cell cycle arrest and inhibited the gene expression related to pathogenesis. Our findings have revealed the anti-giardial efficacy of ADG, suggesting its potential as an agent against Giardia infections. This could offer a natural and low-risk treatment option for giardiasis, reducing the risk of side effects and drug resistance.

Quorum-quenching enzyme Est816 assisted antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in rats.

Introduction: Quorum-quenching enzyme Est816 hydrolyzes the lactone rings of N-acyl homoserine lactones, effectively blocking the biofilm formation and development of Gram-negative bacteria. However, its applications in the oral field is limited. This study aimed to evaluate the efficacy of enzyme Est816 in combination with antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in vitro and in vivo. Methods: The antimicrobial efficacy of enzyme Est816 in combination with minocycline, metronidazole, and amoxicillin was determined using the minimum inhibitory concentration test. The anti-biofilm effect of enzyme Est816 was assessed using scanning electron microscopy, live/dead bacterial staining, crystal violet staining, and real-time quantitative PCR. Biocompatibility of enzyme Est816 was assessed in human gingival fibroblasts (HGF) by staining. A rat model of periodontitis was established to evaluate the effect of enzyme Est816 combined with minocycline using micro-computed tomography and histological staining. Results: Compared to minocycline, metronidazole, and amoxicillin treatment alone, simultaneous treatment with enzyme Est816 increased the sensitivity of biofilm bacteria to antibiotics. Enzyme Est816 with minocycline exhibited the highest rate of biofilm clearance and high biocompatibility. Moreover, the combination of enzyme Est816 with antibiotics improved the antibiofilm effects of the antibiotics synergistically, reducing the expression of the virulence factor leukotoxin gene (ltxA) and fimbria-associated gene (rcpA). Likewise, the combination of enzyme Est816 with minocycline exhibited a remarkable inhibitory effect on bone resorption and inflammation damage in a rat model of periodontitis. Discussion: The combination of enzyme Est816 with antibiotics represents a prospective anti-biofilm strategy with the potential to treat periodontitis.