Metal Chelating Effect Research Articles

The mitigating effects and mechanisms of Bacillus cereus on chronic cadmium poisoning in Litopenaeus vannamei based on histopathological, transcriptomic, and metabolomic analyses

Shrimp are non-negligible victims of cadmium (Cd) contamination, and there is still a lack of strategies for mitigating Cd toxicity in shrimp. Bacillus cereus, with its significant heavy metal (HM) tolerance and chelating effects, is a representative beneficial bacterium to be investigated for mitigating the toxicity of Cd exposure. This study revealed the effects and potential mechanisms of B. cereus in mitigating chronic Cd toxicity in shrimp by analyzing growth performance, hepatopancreatic Cd accumulation, pathology, as well as comprehensive hepatopancreatic transcriptomics and metabolomics in Litopenaeus vannamei. The results showed that shrimp's growth inhibition, hepatopancreatic Cd accumulation and physiological structure damage in B. cereus+chronic Cd group were effectively alleviated compared with the chronic Cd treatment group. The pathways related to amino acid metabolism, glycolipid metabolism, immune response, and antioxidant stress were significantly activated in the B. cereus+chronic Cd group, including glycolysis, pentose phosphate pathway, oxidative phosphorylation, biosynthesis of amino acids, and biosynthesis of unsaturated fatty acids pathways. The key differentially expressed genes (e.g., macrophage migration inhibitory factor, glycine cleavage system H protein, glycine dehydrogenase, phosphoglucomutase-2, asparaginase, ATP synthase subunit, cytochrome c, and 4-hydroxyphenylpyruvate dioxygenase) and metabolites (e.g., L-leucine, D-ribose, gluconic acid, 6-Phosphogluconic acid, sedoheptulose 7-phosphate, 1-Kestose, glyceric acid, arachidic acid, prostaglandins, 12-Keto-tetrahydro-leukotriene B4, and gamma-glutamylcysteine) associated with the above pathways were significantly altered. This study demonstrated that B. cereus is an effective mitigator for the treatment of chronic Cd poisoning in shrimp. B. cereus may play a role in alleviating the toxicity of Cd by enhancing the antioxidant performance, immune defense ability, metabolic stability, and energy demand regulation of shrimp. The study provides reference materials for the study of B. cereus in alleviating Cd toxicity of shrimp and broadens the application of probiotics in treating HM toxicity.

Synthesis and Biological Evaluation of 3-Alkyl(Aryl)-4-(4-methylthio-benzylideneamino)-4,5-dihidro-1H-1,2,4-triazol-5-one Derivatives

In the present study, 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (3c, f, e) reacted with 4-methylthiobenzaldehyde to afford 3-alkyl(aryl)-4-(4-methylthio-benzylideneamino)-4,5-dihidro-1H-1,2,4-triazol-5-ones (4c, f, e). The structures of three new compounds were established from the elemental analysis, IR, 1H NMR, and 13C NMR spectral data. The newly synthesized and recently synthesized 3-alkyl(aryl)-4-(4-methylthiobenzylideneamino)-4,5-dihidro-1H-1,2,4-triazol-5-one derivatives were analyzed using three methods for antioxidant activities. Compound 4a showed the best activity for the metal chelating effect. Furthermore, the compounds' antimicrobial activity was screened.

Phytic acid-doped polypyrrole/graphene oxide nanofillers for the preparation of self-healing anticorrosion coatings with the synergistic physical barrier, passivation and chelating effect

The corrosion protection of organic coatings for metal substrates is generally limited because of the unavoidable coating micropores and cracks, even the coating anticorrosion function will lose when it is damaged. Although the addition of nanofillers into the organic coating matrix can effectively address the above issues, it is challenging to facilely and wholesale construct surface-modified nanofillers with synergistic anticorrosion ability of physical barrier, passivation and chelating effect. In this study, we develop a simple one-pot approach for preparing polypyrrole (PPy) modified graphene oxide (GO) nanofillers with the doping of phytic acid (Ph) (namely GO-PPy@Ph nanoparticles) and then incorporating them into epoxy resin (EP) coating system to form the anticorrosion nanocomposite coatings. The research results display that the GO-PPy@Ph nanoparticles can uniformly disperse in the EP coatings to improve their anti-penetrant ability against corrosive media. And the introduction of GO-PPy@Ph nanoparticles effectively enhances the coating adhesion strength and mechanical performance. Moreover, the anticorrosion tests show that the impedance modulus at 0.01 Hz of GO-PPy@Ph coating after 60-day immersion in 3.5 wt% NaCl solution remains at about 1010 Ω cm2. The dramatical anticorrosive performance of the GO-PPy@Ph coating with self-healing performance is attributed to the synergistic protection of impermeable GO-PPy@Ph nanosheets, passivation function of PPy and metal chelation effect of Ph. This study provides an effective and universal avenue to construct multifunctional nanofillers with the synergistic anticorrosion of high physical barrier, passivation and metal chelating effects for developing anticorrosive nanocomposite coatings with high performances, which have highly attractive potential in the commercialization applications of metal corrosion protection.

Unlocking the power of Libidibia ferrea extracts: antimicrobial, antioxidant, and protective properties for potential use in poultry production

Plant extracts are increasingly recognized as potential prophylactic agents in poultry production due to their diverse bioactive properties. This study investigated the phytochemical and biological properties of Libidibia ferrea (L. ferrea), a plant species native to the Caatinga region of northeastern Brazil. The aim of this study was to identify secondary metabolites and to demonstrate the antimicrobial, antioxidant and protective effects of the plant extract. Three extracts were produced: EHMV, a hydroalcoholic extract from the maceration of pods, and EEMC and EEMV ethanolic extracts from the maceration of peels and pods, respectively, from L. ferrea. High-performance liquid chromatography (HPLC-MS/MS) and atomic absorption spectroscopy (AAS) were used to characterize the metabolites and metals. The antimicrobial activity against Salmonella Galinarum (SG), Salmonella pullorum (SP), Salmonella Heidelberg (SH) and Avian pathogenic Escherichia coli (APEC) was evaluated alone and in combination with probiotic bacteria (Bacillus velenzensis) using agar diffusion and the bactericidal minimum concentration (CBM). The antioxidant potential of the extracts was evaluated in 5 in vitro assays and 6 assays in 3t3 cells. The toxicity of EHMV was tested, and its ability to combat SP infection was demonstrated using a chicken embryo model. The results showed that EHMV exhibited significant antimicrobial activity. The combination of EHMV with BV had synergistic effects, increased antimicrobial activity and induced bacterial sporulation. Composition analysis revealed the presence of 8 compounds, including tannins and phenolic compounds. In vitro antioxidant tests demonstrated that total antioxidant capacity(TAC) activity was increased, and the extract had strong reducing power and notable metal chelating effects. Analysis of 3T3 cells confirmed the protective effect of EHMV against oxidative stress. Toxicity assessments in chicken embryos confirmed the safety of EHMV and its protective effect against SP-induced mortality. EHMV from L. ferrea is rich in proteins and contains essential metabolites that contribute to its antimicrobial and antioxidant properties. When associated with probiotic bacteria such as B. velezensis, this extract increases the inhibition of SH, SG, SP, and APE. The nontoxic nature of EHMV and its protective effects on chicken embryos make it a potential supplement for poultry.

In vitro Antimicrobial Activity, Antioxidant Activity and Synergistic/Antagonistic Effect of Arum maculatum L. in Mersin Province, Turkey

Arum maculatum is used for the treatment of colitis and internal bleeding haemorrhoids among the local people in Turkey. This study was designed to evaluate the antioxidant and antimicrobial activity and protective effects of the leaf and root methanol extract of Arum maculatum L. The phenolic compound content of the root and leaf extract was determined as 207.135±0.07 µg GAE g-1, and 386.054±0.7 µg GAE g extract-1, respectively. The total flavonoid amount was determined as 53.386±0.220 µg QE g-1 and 347.704±0.352 µg QE g-1 extract, respectively. DPPH free radical scavenging of leaf and root extracts was determined as 76.69% and 67.33%, respectively.. The metal chelating effect was determined as 46.585±0.025 mg EDTA/g extract and 35.610±0.087 mg EDTA g extract-1 for roots and leaves, respectively. All extracts were effective against all tested bacteria, and Staphylococcus mutans ATTC 10449 was the most sensitive bacterium with the lowest MIC value (0.20 mg mL-1, 0.81 mg mL-1) for leaf and root extracts, respectively. The biggest diameter of growth inhibition zone (8±2.44 mm, 9±3.26) compared to Chloramphenicol. Arum leaf extracts showed a synergistic effect with OFX against Escherichia coli and Staphylococcus mutans, and Arum root extracts have a synergistic effect with OFX against Staphylococcus aureus and Staphylococcus mutans. These results displayed that A. maculatum has notable natural bioactive compounds with antioxidant and antibacterial properties.

Investigating Holistic Natural Strategies for The Management of Huntington's Disease

Huntington's disease (HD), a multifaceted neurological disorder, presents a complex clinical scenario. An autosomal dominant neurodegenerative ailment called Huntington's disease is brought on by increase in number of CAG (Cytosine-Adenine-Guanine) repeats, which causes the creation of a mutant Huntingtin protein (mHTT) resulting in neuronal death and mental disabilities in human beings. End signs and symptoms can include significant weight loss, difficulty swallowing or breathing, recurrent aspiration pneumonia, declined health and uncontrolled pain. The excessive production of ROS (Reactive Oxygen Species) in nervous tissues is considered a significant risk factor in most of the neurological diseases including HD. Transcriptional regulation, immunological system, and mitochondrial function are all disrupted by mHTT. Although natural products have shown promise in ameliorating symptoms, it is important to note that no singular "phytoconstituent" has been definitively linked to its therapeutic intervention. Nevertheless, certain naturally occurring compounds have exhibited promising outcomes in preclinical investigations. This article focuses on a few phytoconstituents that are known to have a variety of neuroprotective effects through a wide range of biological activities. By stimulating the Nrf2 (Nuclear factor erythroid 2-related factor) pathway and suppressing NF-κB (Nuclear Factor Kappa-light-chain-enhancer of activated B cells), astaxanthin, berberine, and sulfarophane increase the antioxidant and anti-inflammatory activity, resulting in neuroprotection. Curcumin leads to metal chelating effect and decline in reactive oxygen species which are certainly one among the vital processes to impede and manage the disorders causing neurodegeneration including HD. This affects the upregulation of HSPs (Heat Shock Proteins) which helps in HD management. Naringin reduces level of oxidative stress and inflammation by free radical scavenging, NF-κB stimulates cell survival and prevents apoptosis by upregulating anti-apoptotic genes expression and downregulating proapoptotic genes.

Determination of the antioxidant and enzyme-inhibiting activities and evaluation of selected terpenes' ADMET properties: in vitro and in silico approaches

The in vitro antioxidant capacity of eugenol, eucalyptol, linalool, and carvacrol was performed using six test systems: phosphomolybdenum, DPPH (2,2′-diphenyl-1-picrylhydrazyl radical), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate), CUPRAC (cupric ion reducing antioxidant capacity), FRAP (Ferric reducing ability of plasma), and metal chelating effect. Their inhibitory activities on cholinesterases, α-amylase, α-glucosidase, and tyrosinase were assessed as well. Molecular docking helped to explain the obtained outcomes while in silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) prediction served for assessing the physicochemical and pharmacokinetic profiles. Our findings showed that the examined terpenes have promising antioxidative activity with eugenol and carvacrol displaying the highest efficiency. Linalool presented the highest anti-AChE and anti-tyrosinase activities (7.931 ± 0.034 mg GALAE/g and 58.707 ± 5.120 mg KAE/g, respectively). Eucalyptol exhibited the strongest anti-BChE activity (2.704 ± 0.025 mg GALAE/g), while carvacrol exhibited the highest rates for α-glucosidase and α-amylase inhibition (1.414 ± 0.042 and 1.023 ± 0.054 mM ACAE/g, respectively). Molecular docking revealed that all compounds interacted in varied ways with the five enzymes’ active sites. Excellent binding profiles and greatest inhibitory activity to AChE (−7.4 kcal/mol), α-glucosidase (−6.5 kcal/mol), and α-amylase (−6.5 kcal/mol) was attributed to carvacrol. As regards to tyrosinase, eugenol (−6.2 kcal/mol) was the potent one whereas carvacrol and eugenol (−6.5 kcal/mol for both) strongly interacted with BChE. Furthermore, in silico ADMET-related physicochemical and pharmacokinetic properties revealed good profiles. To sum up, here we demonstrate the powerful antioxidant potency and enzymatic inhibitory effects of the four terpenes which may enable the discovery of lead compounds that are extremely potent antioxidants and enzyme inhibitors.

(Invited) empowering Triboelectric Nanogenerator with Functional Polymers for Environment Monitoring

Triboelectric nanogenerator (TENG) proves useful as self-powered sensor. Integration of TENG with functional polymers empowers TENG to exhibit new functionalities and stimuli responsiveness. This study describes the evaluation of spiropyran-functionalized polymer (P1) and guanidinium-functionalized polymers (2 Gdm.) as new materials for TENG, which both show tunable triboelectric output voltage in response to various environmental cues including UV irradiation, humidity change, metal ions and the presence of bacteria. Spiropyran isomerizes to merocyanine upon UV irradiation for 100s (6-8W), resulting in a decrease in output voltage from 100 V to 65 V. In addition, the output voltage is inversely proportional to the irradiation time. Noting high humidity (RH) generally limits the performance of conventional TENGs, such that the output voltage decreases as RH increases. The output voltage of P1 decreases by 48% (from 100V to 52V) and the output voltage of 2 Gdm. decreases by 85% (from 100V to 15V) as the RH changes from 25% to 88%, which is a common behavior of TENG under high humidity. In contrast, the output voltage of the UV irradiated P1 TENG increases by 30% (from 65V to 80V). Because merocyanine is capable of chelating with metal ions to form metal complexes, we also evaluate the effect of metal chelation on triboelectric voltage output. Chelation with copper(II) ions result in restoration of output voltage to ~100V, suggesting the relative position in triboelectric series can be modulated by metal complexation. For guanidinium-functionalized polymers, 2Gdm., the inherent antimicrobial properties of guanidinium side groups enables TENG to be sensitive to both gram-positive and gram-negative bacteria at a concentration of 105 CFU/mL, resulting in decreasing output voltage as bacteria concentration increases. These results demonstrate that the functionalized polymers can be used as a responsive motif to realize smart TENG systems, which exhibits sensitivity to UV irradiation, changes in humidity, and the presence of metal ions or bacteria.

Reaction kinetics of aspalathin degradation and flavanone isomer formation in aqueous model solutions: Effect of temperature, pH and metal chelators

The poor stability of aspalathin in aqueous solutions is a major challenge in delivering a shelf-stable ready-to-drink (RTD) green rooibos iced tea. The kinetics of aspalathin degradation and the formation of eriodictyol glucoside isomers [(S/R)-6-β-D-glucopyranosyleriodictyol and (S/R)-8-β-D-glucopyranosyleriodictyol] in aqueous buffers were modeled to understand and predict aspalathin losses during heat processing. The effects of temperature and pH on the rate constants of aspalathin degradation and eriodictyol glucoside isomer formation were determined in a 0.1 M phosphate buffer with 5.7 mM citric acid. The zero-order model best described the reaction kinetics of aspalathin degradation and eriodictyol glucoside isomer formation. Increasing the temperature and pH increased the reaction rate constants. The activation energies of the reactions were much lower at pH 6 than at pH 4, indicating that pH affected the temperature dependence of the reactions. The 8-C-glucosyl eriodictyol derivatives (RE8G and SE8G) formed at much lower rates than the 6-C-glucosyl eriodictyol derivatives (RE6G and SE6G). The metal chelators, citric acid, citrate and EDTA, drastically reduced the reaction rate constants, indicating the catalytic role of metal ions in aspalathin autoxidation. The results of the study could assist manufacturers to improve the shelf life of rooibos RTD beverages by changing the formulation and adjusting heat processing conditions.

Synthesis of Nano-Crystalline Whiskers of Cheese and Their Efficacy against Cadmium Toxicity

Context and objective: A novel method of fabricating probiotic nanowhiskers—using pure cheese as a source of probiotics, sans metal/chemical surfactants—is reported in the present study. Materials and methods: This was followed by an extensive characterization; FTIR spectroscopy, X-ray diffraction, particle size measurements, and transmission electron microscopy. Thermal analysis via differential scanning calorimetry (DSC) and n screening of the volatile compounds via gas chromatography/mass spectroscopy (GC-MS) was used to assess the purity of the nano-crystalline whiskers. Additionally, the anti-oxidant status and the metal-chelating effect of the nanowhiskers was evaluated in Wistar rats exposed to cadmium chloride hydrate (70 ppm) for 35 days. Group I was the positive control and groups II and III were exposed to Cd, with group III being treated with the cheese nanowhiskers (100 mL/L) in drinking water. Results: The nanoparticles were 112 nm in size (PDI 0.484) with the illustrated whisker/elongated shape being crystalline in nature. Lipid peroxidation was significantly enhanced followed by a marked bioaccumulation of Cd in the target organs. Discussion: Co-treatment with cheese nanowhiskers led to a marked reversal in the Cd-induced modulations in the endpoints evaluated. Conclusions: It is suggested that a dietary intervention in the form of a nano-probiotic supplement such as cheese is a prospective remedy for heavy metal toxicity/oxidative damage, being safe and efficacious.

Systematic Review on Characterization of Tannase from Agricultural By-Products

Tannin-rich compounds are widely produced as by-products of many agro-industrial processes. Tannase is an attractive hydrolase for the bioconversion of tannin-rich materials into value-added products by accelerating the hydrolysis of ester and depside linkages. It has opened new opportunities in several industrial sectors, such as food, drinks, and medicines. Primary sources of tannase are microorganisms, particularly bacteria. Tannases or tannin acyl hydrolases, are an important group of biotechnologically relevant enzymes in several industrial applications. Microbial tannases are mostly induced extracellular enzymes produced by submerged and solid-state fermentation. Tannins containing low-value agro-industrial wastes are being extensively used in industries. This review provides a more in-depth knowledge of the research related to the biochemical characteristics of the tannase enzyme activity (in terms of molecular weight, the effect of pH, the effect of temperature, the effect of metal ions, inhibitor, and chelator), extraction, and purification methods. Additionally, the potential use of agricultural waste as a substrate for tannase production has also been reviewed, including the utilization of pomegranate peel waste (PmPW), banana peel waste (BPW), or potato peel waste (PtPW).

Evaluation of In vitro Antioxidant, Antimicrobial and Cytotoxicity Activities of Orthosiphon Pallidus Royle

Objective: The objective of present research work was to evaluate the in vitro antioxidant, antimicrobial and cytotoxicity activity of Orthosiphon pallidus Royle.
 Methods: Total phenolic and flavonoid content of hydroalcoholic extract (50:50) of Orthosiphon pallidus Royle hydroalcoholic extract (OPRHE) was estimated and the in vitro antioxidant activity was determined using ABTS radical scavenging assay and metal chelating assay. Antimicrobial activity was investigated by agar well diffusion method and MIC was determined. Cytotoxic assay was measured by the SRB method against breast cancer cell lines (MDA-MB-231 and MCF-7) using Rapamycin as standard drug. 
 Results: The total phenolic and flavonoid content of the hydroalcoholic extract of OPRHE was estimated and the In vitro antioxidant activity was determined using the ABTS radical scavenging assay and metal chelating assay. Antimicrobial activity was investigated by the agar well diffusion method and MIC was determined. The cytotoxic assay was measured by the SRB method against breast cancer cell lines (MDA-MB-231 and MCF-7) using Rapamycin as standard drug. The total phenolic and flavonoid content of OPRHE was found to be 228.86±0.19 mg gallic acid equivalents/ g plant extract, and 735.86±1.09 mg quercetin equivalents/ g plant extract, respectively. The IC50 value was found to be 59.22±1.28 µg/ml for extract, and that of standard compound gallic acid & BHT was 1.12±0.42 µg/ml and 3.25 ±1.12µg/ml. OPRHE showed a maximum metal chelating effect of 81.21 % at 600 µg/ml. Antimicrobial activity showed the bacterial strain showed the highest zone of inhibition when compared to the fungal strain. The percentage of cytotoxicity was increasing with the increase in concentration steadily up to 7.5 µg/ml on both the cell lines and the CTC50 value of MCF-7 and MDA-MB-231 cell lines was 153.64 & 213.056 μg/ml while rapamycin standard drug showed a CT50 value of 3.86 & 4.091 μg/ml caused 50 % cytotoxicity. 
 Conclusion: The results of the present investigation demonstrated significant variations in the antioxidant, antimicrobial and cytotoxic effects of hydro alcoholic extract. These data could be helpful in isolation of pure potent compounds with good biological activities from the extract of plant.

Harnessing the Dual Antimicrobial Mechanism of Action with Fe(8-Hydroxyquinoline)3 to Develop a Topical Ointment for Mupirocin-Resistant MRSA Infections.

8-Hydroxyquinoline (8-hq) exhibits potent antimicrobial activity against Staphylococcus aureus (SA) bacteria with MIC = 16.0-32.0 µM owing to its ability to chelate metal ions such as Mn2+, Zn2+, and Cu2+ to disrupt metal homeostasis in bacterial cells. We demonstrate that Fe(8-hq)3, the 1:3 complex formed between Fe(III) and 8-hq, can readily transport Fe(III) across the bacterial cell membrane and deliver iron into the bacterial cell, thus, harnessing a dual antimicrobial mechanism of action that combines the bactericidal activity of iron with the metal chelating effect of 8-hq to kill bacteria. As a result, the antimicrobial potency of Fe(8-hq)3 is significantly enhanced in comparison with 8-hq. Resistance development by SA toward Fe(8-hq)3 is considerably delayed as compared with ciprofloxacin and 8-hq. Fe(8-hq)3 can also overcome the 8-hq and mupirocin resistance developed in the SA mutant and MRSA mutant bacteria, respectively. Fe(8-hq)3 can stimulate M1-like macrophage polarization of RAW 264.7 cells to kill the SA internalized in such macrophages. Fe(8-hq)3 exhibits a synergistic effect with both ciprofloxacin and imipenem, showing potential for combination therapies with topical and systemic antibiotics for more serious MRSA infections. The in vivo antimicrobial efficacy of a 2% Fe(8-hq)3 topical ointment is confirmed by the use of a murine model with skin wound infection by bioluminescent SA with a reduction of the bacterial burden by 99 ± 0.5%, indicating that this non-antibiotic iron complex has therapeutic potential for skin and soft tissue infections (SSTIs).

Chemical Characterization and Multidirectional Biological Effects of Different Solvent Extracts of Arum elongatum: in Vitro and in Silico Approaches.

Arum elongatum (Araceae) is widely used traditionally for the treatment of abdominal pain, arterial hypertension, diabetes mellitus, rheumatism and hemorrhoids. This study investigated the antioxidant properties, individual phenolic compounds, total phenolic and total flavonoid contents (HPLC/MS analysis), reducing power and metal chelating effects of four extracts obtained from A. elongatum (ethyl acetate (EA), methanol (MeOH), methanol/water (MeOH/water) and infusion). The inhibitory activity of the extracts were also determined against acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase and glucosidase enzymes. The MeOH/water extracts contained the highest amount of phenolic contents (28.85 mg GAE/g) while the highest total flavonoid content was obtained with MeOH extract (36.77 mg RE/g). MeOH/water demonstrated highest antioxidant activity against DPPH⋅ radical at 38.90 mg Trolox equivalent per gram. The infusion extract was the most active against ABTS+ ⋅ (133.08 mg TE/g). MeOH/water extract showed the highest reducing abilities with the CUPRAC value of 102.22 mg TE/g and the FRAP value of 68.50 mg TE/g. A strong metal chelating effect was observed with MeOH/water extract (35.72 mg EDTAE/g). The PBD values of the extracts ranged from 1.01 to 2.17 mmol TE/g. EA extract displayed the highest inhibitory activity against AChE (2.32 mg GALAE/g), BChE (3.80 mg GALAE/g), α-amylase (0.56 mmol ACAE/g) and α-glucosidase (9.16 mmol ACAE/g) enzymes. Infusion extract was the most active against tyrosinase enzyme with a value of 83.33 mg KAE/g. A total of 28 compounds were identified from the different extracts. The compounds present in the highest concentration were chlorogenic acids, 4-hydroxybenzoic acid, caffeic acid, p-coumaric acid, ferulic acid, isoquercitrin, delphindin 3,5-diglucoside, kaempferol-3-glucoside and hyperoside. The biological activities of A. elongatum extracts could be due to the presence of compounds such as gallic acid, chlorogenic acids, ellagic acid, epicatechin, catechin, kaempferol, 4-hydroxybenzoic acid, caffeic acid, p-coumaric acid, ferulic acid, quercetin, isoquercitrin, and hyperoside. Extracts of A. elongatum showed promising biological activities which warrants further investigations in an endeavor to develop biopharmaceuticals.

Effect of solvents of extreme polarities on the antioxidative and cytotoxic profiles of single and combined tropical spices

Objective: To assess the possible augmented phytochemical constituents, antioxidant and cytotoxicity activities of hexane and hydroethanol extracts of five combined tropical spices. Methods: Powdered samples from five dried tropical spices [Zingiber officinale Rosc., Xylopia aethiopica (Dun.) A. Rich, Piper guineense Schum & Thonn, Myristica fragrans Houtt. and Allium sativum L.] were separately and in combination extracted with hexane (HX) and hydroethanol (50:50) (HE). Both extracts of the single spices (Ssp) and mixed spices (Mxsp) were evaluated for total phenolic content (TPC), total flavonoid content (TFC) and estimation of antioxidant activities through 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azino-bis (3-ethylbenzothiazoline-6)-sulphonic acid (ABTS), hydroxyl radical (HR) scavenging and reducing power (RP) assays as well as metal chelating (MC) capability. The tetrazolium-based colorimetric cellular (MTT) assay was utilized to assess their possible cytotoxic effect on Vero cells. Results: The study revealed that the HX (75.28 ± 10.07 mggallic acid equivalent/mL) and HE (19.00±3.21 mg quercetin equivalent/g) extracts of Mxsp had the highest TPC and TFC respectively when compared with corresponding extracts of Ssp. The antioxidant efficacy revealed that the HE extract of Mxsp depicted the highest DPPH (median inhibitory concentration (IC50): 0.09 ± 0.03 mg/mL), ABTS (IC50: 0.21 ± 0.03 mg/mL) and HR (IC50: 0.63 ± 0.92 mg/mL) scavenging activities respectively. The best MC effect and potent RP activity were observed in the HX extracts of ginger (IC50: 0.11 ± 0.03 mg/mL) and Mxsp (2.85 ± 0.11 mg/mL) respectively. The MTT assay revealed that Ssp and Mxsp were not cytotoxic to Vero cells with median lethal concentration (LC50) values ranging from 0.13-0.48 mg/mL. Conclusion: This study suggests that Mxsp contains more phytochemical compounds and exhibits better antioxidant activity than Ssp. Moreover, both extracts of Ssp and Mxsp may be considered safe for consumption at specified concentrations.

Microwave-assisted green synthesis, characterization, and antioxidant activity of silver nanoparticles using the aqueous extract of Cistus creticus

Microwave-assisted single-step phytosynthesis of silver nanoparticles were synthesized with Cistus creticus leaf extract for the first time in the present study. The synthesized nanoparticles analyzed by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX). The results reveal that the UV-visible spectrum indicates peaks at 385.5 nm confirming the biosynthesis of CcAgNPs. SEM –EDX analysis showed the formation of spherical morphology and the element composition mostly belongs to silver. The particles size were between 10 and 20 nm by TEM analysis. Antioxidant activity of extract and CcAgNPs were determined using the DPPH• scavenging, CUPRAC assay, and metal chelating activities. Silver nanoparticles synthesized from C. creticus (65.84%) showed lower activity than standard and C. creticus extracts (80.44%). Cistus creticus leaf extract showed a metal chelating effect of 27.07%, CcAgNPs % 21.21 and EDTA (1 mg/mL) used as a standard, 88.05%. According to CUPRAC antioxidant test results, CcAgNPs were found to be equivalent to 3.171 ± 0.021 Eq µg/mL Trolox and 22.789 ± 0.116 Eq µg Ascorbic acid/mL at 1 mg/ml concentration. Silver nanoparticles synthesized from the C. creticus plant will shed light on useful studies to be done in the future to reveal the antioxidant, antimicrobial and anticancer effects.

Back Interface Passivation for Efficient Low-Bandgap Perovskite Solar Cells and Photodetectors.

Low-bandgap (Eg~1.25 eV) mixed tin-lead (Sn-Pb) perovskites are promising candidates for efficient solar cells and self-powered photodetectors; however, they suffer from huge amounts of defects due to the unintentional p-type self-doping. In this work, the synergistic effects of maltol and phenyl-C61-butyric acid methyl ester (PCBM) were achieved to improve the performance of low-bandgap perovskite solar cells (PSCs) and unbiased perovskite photodetectors (PPDs) by passivating the defects and tuning charge transfer dynamics. Maltol eliminated the Sn-related traps in perovskite films through a strong metal chelating effect, whereas PCBM elevated the built-in electric potential and thus improved voltage through the spike energy alignment. Combining both advantages of maltol and PCBM, high-quality perovskite films were obtained, enabling low-bandgap PSCs with the best efficiency of 20.62%. Moreover, the optimized PSCs were further applied as self-powered PPDs in a visible light communication system with a response time of 0.736 μs, presenting a satisfactory audio transmission capability.

Effects of Axonal Demyelination, Inflammatory Cytokines and Divalent Cation Chelators on Thalamic HCN Channels and Oscillatory Bursting.

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is characterized by the progressive loss of oligodendrocytes and myelin and is associated with thalamic dysfunction. Cuprizone (CPZ)-induced general demyelination in rodents is a valuable model for studying different aspects of MS pathology. CPZ feeding is associated with the altered distribution and expression of different ion channels along neuronal somata and axons. However, it is largely unknown whether the copper chelator CPZ directly influences ion channels. Therefore, we assessed the effects of different divalent cations (copper; zinc) and trace metal chelators (EDTA; Tricine; the water-soluble derivative of CPZ, BiMPi) on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that are major mediators of thalamic function and pathology. In addition, alterations of HCN channels induced by CPZ treatment and MS-related proinflammatory cytokines (IL-1β; IL-6; INF-α; INF-β) were characterized in C57Bl/6J mice. Thus, the hyperpolarization-activated inward current (Ih) was recorded in thalamocortical (TC) neurons and heterologous expression systems (mHCN2 expressing HEK cells; hHCN4 expressing oocytes). A number of electrophysiological characteristics of Ih (potential of half-maximal activation (V0.5); current density; activation kinetics) were unchanged following the extracellular application of trace metals and divalent cation chelators to native neurons, cell cultures or oocytes. Mice were fed a diet containing 0.2% CPZ for 35 days, resulting in general demyelination in the brain. Withdrawal of CPZ from the diet resulted in rapid remyelination, the effects of which were assessed at three time points after stopping CPZ feeding (Day1, Day7, Day25). In TC neurons, Ih was decreased on Day1 and Day25 and revealed a transient increased availability on Day7. In addition, we challenged naive TC neurons with INF-α and IL-1β. It was found that Ih parameters were differentially altered by the application of the two cytokines to thalamic cells, while IL-1β increased the availability of HCN channels (depolarized V0.5; increased current density) and the excitability of TC neurons (depolarized resting membrane potential (RMP); increased the number of action potentials (APs); produced a larger voltage sag; promoted higher input resistance; increased the number of burst spikes; hyperpolarized the AP threshold), INF-α mediated contrary effects. The effect of cytokine modulation on thalamic bursting was further assessed in horizontal slices and a computational model of slow thalamic oscillations. Here, IL-1β and INF-α increased and reduced oscillatory bursting, respectively. We conclude that HCN channels are not directly modulated by trace metals and divalent cation chelators but are subject to modulation by different MS-related cytokines.

Exploration of the Plausible Mechanism of Ethambutol Induced Ocular Toxicity by Using Proteomics Informed Physiologically Based Pharmacokinetic (PBPK) Modeling.

Ethambutol (EMB) is a first-line anti-tubercular drug that is known to cause optic neuropathy. The exact mechanism of its eye toxicity is unknown; however, proposition is metal chelating effect of both EMB and its metabolite 2,2'-(ethylenediamino)-dibutyric acid (EDBA). The latter is formed by sequential metabolism of EMB by alcohol dehydrogenases (ADHs) and aldehyde dehydrogenases (ALDHs). The purpose of this study was to predict thelevels of drug and EDBA in theeye using physiologically based pharmacokinetic (PBPK) modeling. The PBPK model of EMB was developed using GastroPlus. The intrinsic hepatic clearance of ALDH, calculated by themodel, was scaled down using proteomics data to estimate the rate of formation of EDBA in theeye. Additionally, the comparative permeability of EMB and EDBA was assessed by employing in silico and in vitro approaches. The rate of formation of EDBA in the eye and permeability data were then incorporated in a compartmental model to predict the ocular levels of EMB and EDBA. The simulation results of compartmental model highlighted that there was an on-site formation of EDBA upon metabolism of EMB. Furthermore, in silico and in vitro studies revealed that EDBA possessed much lower permeability than EMB. These observations meant that once EDBA was formed in the eye, it was not permeated out and hence achieved higher ocular concentration. The on-site formation of EDBA in the eye, its higher local concentration due to lower ocular clearance and its pre-known characteristic to chelate metal species better explains the ocular toxicity shown by EMB.

Antioxidant and antihypertensive activity of Gouda cheese at different stages of ripening.

In Mexico, local ripened cheeses such as Chihuahua, Ranchero, and Cotija are produced, being consumed in great quantities together with imported cheeses. Proteolysis that takes place during ripening generates bioactive peptides; in this way the cheese acquires potential as a functional food. The ripening process of Gouda cheese was studied based on its bromatological and sensorial properties, bioactivity, and peptide profile. Ripened cheese met bromatological standard parameters and showed higher overall acceptability. After 90days, bioactivity reached maximum values for radical scavenging (6.6%), ferric reducing power (11.2%), metal chelating effect (49%), and angiotensin I-converting enzyme inhibitory activity (66.2%). Eight peptides were identified, four from αS1-casein, f(1-9, 1-13, 1-14, and 25-36), and four from β-casein, f(11-28, 60-63, 193-209, and 197-205). Ripening of Gouda cheese results in a product with functional potential due to the presence of peptides with biological activity. Additionally, the methodology proposed in this work could be used by the dairy industry to monitor the manufacturing process and ripening of other types of cheeses.