Detection of nitric oxide radical and determination of its scavenging activity by antioxidants using spectrophotometric and spectrofluorometric methods

Optimized Fermentation Conditions of Pulses Increase Scavenging Capacity and Markers of Anti-Diabetic Properties

Fermented pulses offer health benefits due to their antioxidant and antidiabetic properties. The objective was to optimize the fermentation conditions of black bean (BB), black eyed pea (BEP), green split pea (GSP), red lentil (RL), and pinto bean (PB), using Lactiplantibacillus plantarum 299v (Lp299v), based on the antioxidant-scavenging capacity and the ability to modulate type-2 diabetes markers. Pulses were grounded, dispersed in water, hydrolyzed with α-amylase, and pasteurized and inoculated with Lp299v. Optimization was performed by using the Box-Behnken response surface methodology, with the fermentation time, bacterial concentration, and flour concentration as variables. The values of antioxidant capacity measured as 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging of RL, BEP, PB, BB, and GSP were 57%, 68%, 71%, 72%, and 83%, respectively, under optimal conditions (8-9 h, 0.76-3.5 × 109 a colony-forming unit (CFU)/mL, and 5.5-15 g flour/100 mL). These models demonstrated strong predictive power (p < 0.01) and a non-significant lack of fit (p ≥ 0.05). Additionally, fermentation increased the soluble protein content (3-10 mg/mL) and significantly inhibited dipeptidyl peptidase-IV and α-glucosidase activities by 40-70% and 30-60%, respectively. These results suggest that fermentation with Lp299v enhances the nutritional and functional quality of pulses, producing bioactive ingredients with antioxidant and antidiabetic potential. These functional ingredients may be used in the development of dietary interventions or as part of health-promoting foods, especially those targeted at the management of type-2 diabetes.

Peroxynitrite as biomarker to evaluate the rehabilitation of cisplatin in the resistant cells with miR-125a-5p by using fluorescent assay

Reactive oxygen species (ROS) play a dual role in the chemotherapy of cancer with cisplatin, providing both anti-tumor effects and contributing to drug resistance at various stages of treatment which seriously affects treatment effectiveness. The detailed mechanism of ROS is urgently necessary to be explored. To address this issue in the non-small-cell lung cancer (NSCLC) with cisplatin-resistance, a reliable assay was developed by synthesizing and characterizing an interesting near-infrared (NIR) ONOO- probe BPB with high specificity, quick response (<30 s) and excellent limitation of detection (59 nM), which was further convinced through living cell imaging techniques providing different fluorescence variation between cell and cuvette. All the results revealed that ONOO- might be a practical biomarker to comprehend the detail molecular mechanism in cisplatin-resistant A549 cells. The elevated levels of ONOO- in cisplatin-resistant A549 cells, accompanied by a significant reduction in fluorescence following the knockout of miR-125a-5p in these cells and strong fluorescence without knockout of miR-125a-5p ignoring the presence of cisplatin. Comparing with cisplatin-resistant cells, the control would provide a rational background and then showed distinct fluorescence from BPB with ONOO- toward cisplatin. This assay offers a promising tool for exploring the molecular mechanisms associated with miR-125a-5p and its potential linkage to therapeutic efficacy involving ONOO- signaling. By utilizing this innovative assay, researchers can gain valuable insights into the treatment strategies and underlying mechanisms of cisplatin-resistant cancers, which should be beneficial to the therapy of cancers.

A novel mitochondrial-targeted fluorescent probe for ratiometric imaging of nitric oxide in cells and zebrafish

Nitric oxide (NO) is a key signaling molecule that regulates energy metabolism, apoptosis, and antioxidant balance within mitochondria. It is closely associated with the development of cardiovascular diseases, neurodegenerative diseases, and cancer. Therefore, developing fluorescent probes capable of accurately detecting NO levels in mitochondria is essential for understanding disease mechanisms and clinical diagnostics. In this study, we developed a novel fluorescent probe based on the isophorone fluorophore. This probe achieves high sensitivity and specific ratiometric detection of NO in mitochondria by regulating the intramolecular charge transfer (ICT) effect. The probe emits red fluorescence before reacting with NO, and the addition of NO triggers an amine-NO addition reaction that inhibits the ICT effect, resulting in a color change to yellow-green fluorescence. This ratiometric fluorescence response provides a new method for quantitatively detecting NO. Additionally, the probe has a significant Stokes shift and good ratiometric wavelength separation, enhancing detection accuracy. It localizes explicitly to mitochondria, directly reflecting changes in mitochondrial NO concentration. Experiments in HeLa cells and zebrafish models have demonstrated the potential application of the probe in diagnosing and studying NO-related diseases. This provides new strategies and tools for researching the biological functions of NO and the early diagnosis of related diseases.

BBPT attenuated 6-OHDA-induced toxicity by modulating oxidative stress, apoptotic, and inflammatory proteins in primary neurons and rat models of Parkinson's disease

Parkinson's disease (PD) results from the degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc). Adenosine A2AR acting through the striato-pallidal pathway has emerged as a non-dopaminergic target in the therapy of PD. In the present work, the anti-parkinsonian potential of (4E)-4-(4-bromobenzylideneamino)-3-phenyl-2,3-dihydro-2-thioxo- thiazole-5-carbonitrile (BBPT) was explored. BBPT exhibited significant antioxidant activity in situ. In the MTT assay, the BBPT treatment showed insignificant toxicity to the primary midbrain neuronal (PMDN) cells. 6-OHDA induced PMDN cells, 3 h post-treated with BBPT showed 80-85 % survival of the cells and restoration of dopamine and TNF-α levels. The acute and sub-acute toxicity test for BBPT was performed with Sprague Dawley (SD) rats. In toxicity assay, any significant physical, hematological, or biochemical changes in the rats were not observed. To evaluate the effect of BBPT in vivo, a 6-OHDA-induced unilaterally lesioned SD rat model of PD was established. We observed that the BBPT treatment improved the behavioral symptoms in 6-OHDA-induced unilaterally lesioned rats. The proteins of 6-OHDA-induced BBPT-treated rats were isolated from the brain tissue to assess the antioxidant effect (GSH, catalase, SOD, lipid-peroxidation, nitrite), dopamine levels, and the restoration in the apoptosis and inflammation. Our results demonstrated that BBPT increased the anti-oxidant enzyme levels, restored the caspase-3/Bcl-2 levels to arrest apoptosis, and attenuated the TNF-α/IL-6 levels, thus restoring the neuronal damage in unilaterally lesioned 6-OHDA-induced SD rats. Precisely, the findings suggested that BBPT possessed significant anti-parkinsonian activity and has the potential to prevent dopaminergic neurodegeneration.

Intrinsic oxidase-mimicking activity of nitrite upon visible light illumination and its colorimetric detection in saliva

Small molecules with enzyme-like properties have recently attracted considerable attention. Herein, we discovered that nitrite possesses intrinsic oxidase-mimicking activity upon visible light, catalyzing the oxidation of the typical chromogenic substrate in the absence of H2O2. Notably, nitrite exhibited a markedly high value of Kcat, approximately 4, 7, and 4000-fold greater than that of Acr+-Mes, Eosin Y, and Diacetyl, respectively. Comprehensive investigation elucidated that O2•⁻ and •OH are the primary reactive oxygen species (ROS) responsible for the oxidation of 3,3',5,5'-tetramethylbenzidine dihydrochloride hydrate (TMB). Leveraging the linear correlation between the absorbance of oxidized TMB (oxTMB) at 652 nm and nitrite concentration, a simple colorimetric approach for nitrite detection was successfully established in the range of 1-75 μM with a detection limit of 0.14 μM. Moreover, the proposed strategy could be applied to determine the nitrite concentration in saliva, exhibiting a great prospect for clinical diagnosis. This work contributes novel insights into the exploration of small-molecule enzyme mimics.

Novel sulfamethoxazole and 1-(2-fluorophenyl) piperazine derivatives as potential apoptotic and antiproliferative agents by inhibition of BCL2; design, synthesis, biological evaluation, and docking studies

In the present study, a novel series of sulfamethoxazole and 1-(2-fluorophenyl) piperazine derivatives were designed, synthesized and characterized by FTIR, IH NMR,13C NMR, Mass spectrometry, CHN data, and evaluated for their efficiency as BCL2 inhibitors that could lead to potential antiproliferative activity. The ten newly synthesized compounds were screened for their therapeutic activity using MDA-MB-231 breast cancer cell lines. All the test compounds exhibited moderate to high cytotoxic activity in MTT assay. Among them, compounds 3e and 6b exhibited promising antitumor activity, as evidenced by their IC50 values of 16.98 and 17.33 μM respectively. In addition, both compounds 3e and 6b displayed potential antioxidant and apoptosis induction properties. The qRT-PCR analysis showed down regulation of BCL2 expression and up regulation of Casp3 expression in 3e and 6b treated MDA-MB-231 cells. Further, the interaction between critical amino acids of the active domains of BCL2 and 3e and 6b was evaluated by MD simulation, and the results reflected the potent inhibitory activities of 3e and 6b. In summary, the novel compounds 3e and 6b demonstrate their potent anti-cancer properties by inducing apoptosis and selectively targeting BCL2 and caspases-3.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-024-04111-6.

Comprehensive insights into fluorescent probes for the determination nitric oxide for diseases diagnosis

Nitric oxide (NO) plays an important role in multiple physiological processes of the body involved in regulation, such as cardiovascular relaxation, neural homeostasis, and immune regulation, etc. The real-time monitoring of NO is of great significance in the investigation of related disease mechanisms and the evaluation of pharmacodynamics. Fluorescent probes are considered as a highly promising approach for pharmaceutical analysis and bioimaging due to their non-invasive character, real-time detection, and high sensitivity. However, there are still some challenges in the determination of biological nitric oxide with fluorescent probes, such as low anti-interference ability, poor function modifiability, and low organ specificity. Therefore, it would be beneficial to develop a new generation of fluorescent probes for real-time bioimaging of NO in vivo after this systematic summary.

Breathable Wearable Smartsensors Deriving from Interface Self-Assembled Film for Tracking l-Cysteine

The advent of wearable sensors heralds a transformation in the continuous, noninvasive analysis of biomarkers critical for disease diagnosis and fitness management. Yet, their advancement is hindered by the functional challenges affiliated with their active sensing analysis layer. Predominantly due to suboptimal intrinsic material properties and inconsistent dispersion leading to aggregation, thus compromising sensor repeatability and performance. Herein, an innovative approach to the functionalization of wearable electrochemical sensors was introduced, specifically addressing these limitations. The method involves a proton-induced self-assembly technique at the organic-water (O/W) interface, facilitating the generation of biomarker-responsive films. This research offers flexible, breathable sensor capable of real-time precision tracking l-cysteine (l-Cys) precision tracking. Utilizing an activation mechanism for Prussian blue nanoparticles by hydrogen peroxide, the catalytic core exhibits a specific response to l-Cys. The implications of this study refine the fabrication of film-based analysis electrodes for wearable sensing applications and the broader utilization of two-dimensional materials in functional-specific response films. Findings illuminate the feasibility of this novel strategy for precise biomarker tracking and extend to pave the way for constructing high-performance electrocatalytic analytical interfaces.

Development of an innovative turn-on fluorescent probe for targeted in-vivo detection of nitric oxide in rat brain extracts as a biomarker for migraine disease

Nitric oxide (NO) is one of the reactive nitrogen species (RNS) that has been proposed to be a key signaling molecule in migraine. Migraine is a neurological disorder that is linked to irregular NO levels, which necessitates precise NO quantification for effective diagnosis and treatment. This work introduces a novel fluorescent probe, 2,3-diaminonaphthelene-1,4-dione (DAND), which was designed and synthesized to selectively detect NO in-vitro and in-vivo as a migraine biomarker. DAND boasts high aqueous solubility, biocompatibility, and facile synthesis, which enable highly selective and sensitive detection of NO under physiological conditions. NO reacts with diamine moieties (recognition sites) of DAND, results in the formation of a highly fluorescent product (DAND-NO) known as 1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione at λem 450 nm. The fluorescence turn-on sensing mechanism operates through an intramolecular charge transfer (ICT) mechanism. To maximize fluorescence signal intensity, parameters including DAND concentration, reaction temperature, reaction time and pH were systematically optimized for sensitive and precise NO determination. The enhanced detection capability (LOD = 0.08 μmol L-1) and high selectivity of the probe make it a promising tool for NO detection in brain tissue homogenates. This demonstrates the potential diagnostic value of the probe for individuals suffering from migraine. Furthermore, this study sheds light on the potential role of zolmitriptan (ZOLM), an antimigraine medication, in modulating NO levels in the brain of rats with nitroglycerin-induced migraine, emphasizing its significant impact on reducing NO levels. The obtained results could have significant implications for understanding how ZOLM affects NO levels and may aid in the development of more targeted and effective migraine treatment strategies.

Exploring the multifaceted effects of Ammi visnaga: subchronic toxicity, antioxidant capacity, immunomodulatory, and anti-inflammatory activities

Ammi visnaga (A. visnaga) is an annual herb that has been used in traditional medicine to treat various ailments attributed to the presence of its bioactive compounds. The purpose of this study was to identify and examine the phytochemical properties of the hydroalcoholic extract of A. visnaga using in vitro and in vivo models. Our findings demonstrated that the extract contained a variety of beneficial components, including phenols, flavonoids, tannins, coumarins, saponins, khellin, and visnagin. The total polyphenolic content and total flavonoid content were 23.26 mg/GAE/g dry weight and 13.26 mg/GAE/g dry weight, respectively. In vitro tests demonstrated that the extract possessed antioxidant properties as evidenced by the ability to scavenge free radicals, including DPPH, ABTS, nitric oxide (NO), phosphomolybdate, and ferric-reducing antioxidant power (FRAP). Further, the extract was found to inhibit hydrogen peroxide (H2O2)-induced hemolysis. In a 90-d in vivo study, female Wistar rats were administered 1 g/kg of A. visnaga extract orally resulting in a significant increase in total white blood cell count. Although morphological changes were observed in the liver, no marked alterations were noted in kidneys and spleen. In a female Swiss albino mice model of acetic acid-induced vascular permeability, A. visnaga significantly inhibited extravasations of Evans blue at doses of 0.5 or 1 g/kg with inhibition percentages of 51 and 65%, respectively, blocking tissue necrosis. The extract also demonstrated potential immunomodulatory properties in mice by enhancing antibody production in response to antigens. In silico molecular docking studies demonstrated a strong affinity between khellin or visnagin and immunomodulatory proteins, NF-κB, p52, and TNF-α. These findings suggest that A. visnaga may be considered a beneficial antioxidant with immunomodulatory properties and might serve as a therapeutic agent to combat certain diseases.

Determination of ketamine using melamine-modified gold nanoparticles

Ketamine is used in medicine because of its anaesthetic and antidepressant effects at low doses. Unfortunately, due to its narcotic effect when used at high doses, its abuse among young people is increasing. It is also one of the most common drugs used in rape. Therefore, there is a need for fast and inexpensive tests that can be performed on-site. With the advancement of nanotechnology, nanoparticle-based approaches have found their place in selective analyses as in many fields. In the developed method, firstly gold nanoparticles were modified with melamine (AuNPs@Mel). Under optimized conditions, hydrogen bonds formed between ketamine and AuNPs@Mel cause the red colour of AuNPs@Mel to shift to blue-purple (i.e. aggregation-induced surface plasmon absorption shift). The association between absorbance and concentration produced a calibration line (curve) having a linearity correlation coefficient of 0.9981 for ketamine concentrations ranging from 4.76 to 47.6 mg L-1. The detection limit of the proposed method was 1.5 mg L-1 and the RSD (relative standard deviation) values of concentrations were changed ranging from 5.2% to 8.2%. The intra-assay and inter-assay measurements using the suggested method resulted in coefficients of variation (CVs) of 5.7% and 8.5%, respectively. Scan transmission electron microscopy (STEM), UV-vis spectrophotometry and FTIR spectroscopy were used to characterize the synthesized and modified AuNPs. Additionally, the procedure was successfully carried out with some interference materials and a real sample of fetal bovine serum. Lastly, using the Student t-test and F tests, the suggested technique was compared to and confirmed against an LC-MS/MS procedure previously published.

Nanomolar Nitric Oxide Concentrations in Living Cells Measured by Means of Fluorescence Correlation Spectroscopy

Measurement of the nitric oxide (NO) concentration in living cells in the physiological nanomolar range is crucial in understanding NO biochemical functions, as well as in characterizing the efficiency and kinetics of NO delivery by NO-releasing drugs. Here, we show that fluorescence correlation spectroscopy (FCS) is perfectly suited for these purposes, due to its sensitivity, selectivity, and spatial resolution. Using the fluorescent indicators, diaminofluoresceins (DAFs), and FCS, we measured the NO concentrations in NO-producing living human primary endothelial cells, as well as NO delivery kinetics, by an external NO donor to the immortal human epithelial living cells. Due to the high spatial resolution of FCS, the NO concentration in different parts of the cells were also measured. The detection of nitric oxide by means of diaminofluoresceins is much more efficient and faster in living cells than in PBS solutions, even though the conversion to the fluorescent form is a multi-step reaction.