Metal Ion Chelating Ability Research Articles

Advancing Polyphenol-Based Nanomedicine for Inflammatory Bowel Disease: Challenges and Opportunities.

Oxidative stress, characterized by excessive production of reactive oxygen species (ROS), is a critical factor in the progression of inflammatory bowel disease (IBD) and presents a potential therapeutic target. Anti-oxidant therapy, aimed at mitigating excessive ROS, is emerging as a cornerstone in IBD treatment. Nanomaterials with robust anti-oxidant properties offer promise by inhibiting inflammation through ROS scavenging, enhancing IBD therapeutic efficacy. Recent focus in ROS scavenging has centered on metal oxide nanoenzymes and polyphenol-based nanomaterials. The primary challenges are the catalytic efficiency of nanoenzymes and the functional integration of these nanomaterials with therapeutic agents. Polyphenols, natural plant extracts, have garnered significant interest due to their potent anti-oxidant properties and unique catechol groups that interact with biomolecules such as proteins and nucleic acids. The strong metal ion chelating ability of catechols enriches the structure and functionality of nanomaterials, improving the physicochemical properties of nanocarriers and enabling innovative designs of multifunctional drug delivery systems (DDSs). Research on polyphenol-based DDSs has expanded to include agents like epigallocatechin gallate, curcumin, resveratrol, tannic acid, and polydopamine. These nanocarriers and anti-oxidants, which incorporate polyphenols, have demonstrated potential anti-oxidant properties in novel DDSs as therapeutic agents to reduce inflammation and as essential components of drug carriers. This review focuses on the design and application of natural polyphenol-based anti-oxidant nanomaterials for IBD treatment, offering a comprehensive discussion on the use of polyphenols in DDSs and the potential challenges posed by their diverse roles in innovative drug delivery strategies, including their impact on the physical and chemical properties of DDSs.

Discovery of novel 5-(2-hydroxyphenyl)-2-phthalide-3(3H)-pyrazolones as balanced multifunctional agents against Alzheimer's disease

Based on previous work, a series of novel 5-(2-hydroxyphenyl)-2-phthalide-3(3H)-pyrazolones derivatives were identified as potential multifunctional therapeutic agents for Alzheimer's disease. Biological evaluation exhibited that these derivatives had great performance against MAO-B, Aβ1-42 aggregation, oxidative stress and metal ion dyshomeostasis. Among them, 10x was selected as the optimal agent for its excellent MAO-B inhibitory activity (IC50 = 0.41 μM, SI > 24.4), good antioxidant activity (1.16 Trolox equivalent) and anti-Aβ aggregation activity (56.03% and 57.51% for inhibition of self- and Cu2+-induced Aβ1-42 aggregation; 81.91% and 82.40% for disaggregation of self- and Cu2+-induced Aβ1-42 fibrils at 25.0 μM). Besides, 10x also exhibited obvious metal-ion chelating ability, anti-neuroinflammation (NO, TNF-α), neuroprotective activity and BBB permeability. More importantly, in vivo behavioral assessment demonstrated 10x could remarkably improve the memory and cognitive impairment in Aβ1-42 induced AD mice model. Overall, these test results indicated 10x could serve as a balanced multifunctional anti-AD agent and deserved further research.

Cross-linking treatment of arabinoxylan improves its antioxidant and hypoglycemic activities after simulated in vitro digestion

The objective of the present study was to evaluate the impact of cross-linking treatment of arabinoxylan (AX) on its structure and physiological functions prior to and after the in vitro gastrointestinal digestion. The AX extracted from triticale bran was cross-linked using laccase. The reaction was monitored spectrophotometrically and verified based on the decrease in the ferulic acid content and an increase in the molecular weight. In comparison to the non-cross-linked AX (A-AX), the cross-linked AX (C-AX) exhibited a higher substitution degree, a more compact microstructure, and higher viscosity in the results of FT-IR, SEM, and rheological tests. The hydroxyl radical scavenging ability and the metal ion chelating ability of C-AX were higher than those of A-AX. After passing through the gastrointestinal tract simulated using an in vitro digestion model, in addition to the retentive larger molecular weight and network structure, the antioxidant activity and the glucosidase inhibition activity of C-AX were higher than those of A-AX. In conclusion, the cross-linking treatment of AX increased its tolerance of the extreme environment during the digestive process by modulating its structural characteristics.

Chenopodium ambrosioides var. ambrosioides leaf extracts possess regenerative and ameliorative effects against mercury-induced hepatotoxicity and nephrotoxicity

Empirical literature reveals the use of Chenopodium ambrosioides var. ambrosioides leaf extract as antipyretic, antimicrobial, antioxidant, cancer chemoprotective, and antidiabetic agent in folklore medicine – with these pharmacological properties linked to its secondary metabolites. There are, however, no adequate information on the possible protective, regenerative, and ameliorative effects on toxicity induced by heavy metals. Hence, the investigations on mercury-induced nephrotoxicity and hepatotoxicity in this study. The leaf extract was profiled using gas chromatographic instrument coupled with mass spectrometer (GC–MS) and revealed 100 metabolites ranging from polyphenols, terpenes, terpenoids, and cardiac glycosides. The antioxidant assays revealed that C. ambrosioides leaf extracts possess antioxidant properties with hexane fraction exhibiting the highest scavenging activities for DPPH (IC50 = 0.02 mg/mL), FRAP (730.92 mg/AAE g), and metal ion chelating ability (IC50 = 3.18 mg/mL). Nephrotoxicity and hepatotoxicity biomarkers using total protein, albumin, total bilirubin, direct bilirubin, catalase, glutathione peroxidase (GPx), reduced glutathione (GSH), creatinine, uric acid, urea, ALT, and AST activities both in the kidney and liver homogenates of Wistar rats revealed significant regenerative improvement which differs significantly at p < 0.05 when compared with experimental rats with toxicant only. In the same vein, the histomorphological analysis showed remarkable hepatocellular regeneration presenting features of normal architectural arrangements of hepatic tissues while acute toxicological studies revealed that the LD50 of C. ambrosioides leaf material is well above 5000 mg/kg. The outcomes of this study showed that the leaf extract exhibited high hepatoprotective and nephroprotective activities as well as being implicated in the discovery of safe, cheaper, and effective therapeutic agents thereby highlighting its importance as a promising industrial crop.

Biosorptive Removal of Cadmium(II) and Copper(II) Using Microwave-Assisted Thiourea-Modified Sorghum bicolor Agrowaste

Sorghum bicolor (S.B.) is used in this work for preparing chemically modified adsorbent for toxic metal ions, i.e., cadmium(II) and copper(II). Thiourea is selected for chemical modification of this plant waste by microwave solid fusion methodology, so that its chelating ability for metal ions can be enhanced in both acidic and basic conditions, in a cheaper and quicker way. Characterization was carried out by different physiochemical means using FT-IR, SEM, etc. An increase in pHpzc value was observed in TSB, which is confirmed by FT-IR analysis. The effect of biosorption process parameters was also studied and found that maximum removal of these toxic ions occurred in slightly acidic pH (5-6) conditions, following pseudo-second-order kinetic model. Boyd plots indicated that film dispersion mode was the rate-determining step. Langmuir model indicated that the maximum metal ion removal capacity of TSB was 17.241 mg/g and 15.151 mg/g for cadmium(II) and copper(II) ions. So, TSB can be used on a larger scale for toxic metal ion removal by Sorghum bicolor waste in a cleaner way.

Effect of Different Drying Methods on Nutrient Quality of the Yellow Mealworm (Tenebrio molitor L.).

Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven drying, vacuum drying or freeze drying, respectively. Proximate composition and fatty acid profile were comparable between the dried larvae. In contrast, larvae color impressions and volatile compound profiles were very much dependent on processing procedure. High-temperature rack oven drying caused pronounced darkening with rather low content of volatiles, pointing toward the progress of Maillard reaction. On the other hand, vacuum drying or freeze drying led to enrichment of volatile Maillard reaction and lipid oxidation intermediates, whose actual sensory relevance needs to be clarified in the future. Beyond sensory and visual importance drying intermediates have to be considered with regard to their metal ion chelating ability; in particular for essential trace elements such as Zn2+. This study found comparable total zinc contents for the differently dried mealworm samples. However, dried larvae, in particular after rack oven drying, had only low zinc accessibility, which was between 20% and 40%. Therefore, bioaccessibility rather than total zinc has to be considered when their contribution to meeting the nutritional requirements for zinc in humans and animals is evaluated.

Biocatalytic Synthesis of a Novel Polyaniline Derivative and Its Usage for Polypropylene Stabilization

The synthesis, characterization, and some physical properties of a new polyaniline derivative (PHCA), produced by horseradish peroxidase (HRP) initiated oxidative polymerization of 2-hydroxy-5-chloroaniline (HCA), are presented. The spectroscopic measurements indicate that PHCA consists of a mixture of branched and linear aniline chain units. Data from antioxidant potential assays show that PHCA exhibits moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity but excellent metal ion chelating ability. The metal chelating ability of PHCA (82.14 ± 2.39%) is about 2 times higher than that of EDTA (30.08 ± 0.81%) at a concentration of 100 μg/mL. In addition, as a potent antioxidant stabilizer, the influence of PHCA on the thermooxidative degradation of polypropylene (PP) is also investigated. The insertion of PHCA into PP matrix improves significantly both the oxidation induction time (OIT) and the onset oxidation temperature (OOT) of virgin PP.

Xylan/chitosan composites prepared by an ionic liquid system with unique antioxidant properties

Antioxidant function and solubility in water are highly desirable in many applications of chitosan. In this paper, a xylan/chitosan composite was prepared in an ionic liquid system using glutaraldehyde as a crosslinking agent. The antioxidant activity, reducing capacity and metal ion chelating ability of the resulting composite were determined. The chemical structure and thermal stability were analyzed by FT-IR, XRD and TGA. The results showed that chitosan was successfully cross-linked with xylan by glutaraldehyde in the ionic liquid system. Compared to pure chitosan, the ABTS·+ scavenging activity of the xylan/chitosan composite increased from 10.56% to 97.59%. After cross-linking with xylan by glutaraldehyde, the reducing power of xylan/chitosan composite increased from 0.054 to 2.109. The capacity of chelating metal ion of the composite also increased from 42.35% to 86.71% compared to that of pure chitosan. An underlying mechanism was proposed to account for the improvement of the chemical properties of the chitosan in the composite.

Fabrication of Conductive Silver Microtubes Using Natural Catkin as a Template.

Catkin, a natural hollow fiber, is used as a template to fabricate light, flexible, and electrically conductive silver microtubes with a high aspect ratio. The template is functionalized with tannic acid (TA)–Fe coordination complexes. Because of the metal ion chelating ability and reducibility of TA, silver nanoparticles (Ag NPs) can be formed in situ on the fiber’s surface. The as-formed Ag NPs can act as nucleation sites in subsequent electroless silver plating, leading to the formation of a compact and uniform silver coating on the microtube. The coating is constructed by densely packed Ag NPs of only 15 ± 5 nm in diameter. Because of the tight accumulation and small size of the Ag NPs, the resulting silver-coated microtubes, without any post-treatment, show an electrical resistivity of 1500 mΩ·cm at a bulk density of 0.6 g·cm–3. We find that the in situ formed nucleation sites and the stirring speed in the electroless plating play important roles in the formation of a silver coating with a high electrical conductivity. This method may be extended to fabricate conductive nanocoatings on other substrates.

Chelating Ability and Microbial Stability of an l-Arginine-Modified Chitosan-Based Environmental Remediation Material

To improve the heavy metal ion chelating ability and the microbiological stability of chitosan (CS), l-arginine (l-Arg) was grafted on CS polymer in the presence of the condensing agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and the coupling reagent N-hydroxysuccinimide (NHS) to prepare a natural polymer-based environmental rehabilitation material: l-arginine-grafted chitosan (CA). The graft mechanism is discussed, and the reaction conditions were optimized. The product was characterized using elemental analysis, infrared spectroscopy (FT-IR) and 13C-NMR spectroscopy (13C-NMR). The optimal reaction conditions were a reactant molar ratio nCS:nArg:nEDC:nNHS of 3:3:3:1, a reaction time of 12 h, and a reaction system pH = 5. Under these conditions, the grafting ratio (GR) was 16.85%, while the product yield (PY) was 90.48%. The results of the adsorption experiments showed that the CA (GR = 16.85%) had a better removal capacity for highly concentrated Cu2+ and Ni2+ ions than CS. The antibacterial activity of the CA was also enhanced. When the GR reached 16.85%, the CA almost completely inhibited the growth of colibacillus and Staphylococcus aureus. Due to its high chelating ability and microbiological stability, this novel metal-ion adsorption material, CA, can be considered to have broad application potential in heavy metal ion-polluted water and soil remediation.

Preparation and evaluation of multidentate ligand-bonded silica chromatographic medium

Iminodisuccinic acid (IDS), a green environment-friendly multidentate chelating agent, was used as a ligand to synthesize IDS-Silica stationary phase under the optimized conditions. The binding capacity of IDS on the stationary phase was measured by potentiometric titration. The chromatographic properties and metal chelating property on IDS-Silica column were investigated. Three standard protein mixtures were separated successfully with IDS-Silica column. The results showed that the IDS-Silica column displayed a typical cation exchange property. The binding characteristics of six different metal ions on IDS-Silica stationary phase were examined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results validated that the variation of binding capacities of metal ions on the stationary phase were consistent with the chelating stability order of the IDS-Silica column for metal ions. Compared with the other silica columns bonded with the three different aminocarboxyl ligands, the bonding amounts of Cu2+ on IDS-Silica column was the largest, which indicated that IDS had stronger chelating ability for metal ions. This characteristic lays the foundation for IDS as a good chromatographic packing used in the field of immobilized metal affinity chromatography (IMAC), thus probably provides an effective solution to reduce the leaking problem of metal ion from IMAC column during protein elution with one competitive agent.

Medicinal attributes of major phenylpropanoids present in cinnamon

BackgroundExcessive production of free radicals has been implicated in many diseases including cancer. They are highly reactive and bring about oxidation of biomolecules i.e., proteins, lipids and nucleic acids which are associated with many degenerative diseases. Natural products acting as antioxidants have ability to neutralize free radicals and their actions and hence they mitigate their harmful effects. The present study was designed to investigate pharmacological properties viz., antioxidant, antibacterial and antiproliferative activities of cinnamaldehyde and eugenol, the two naturally occurring phenylpropanoids present in Cinnamomum spp. and other plants.MethodsThe antioxidant potential of test compounds was evaluated by measuring DPPH free radical scavenging, reducing power and metal ion chelating activities. Protection against membrane damage was assayed by inhibition of lipid peroxidation in rat liver homogenate. Antibacterial activity was measured by Kirby-Bauer disc diffusion method while antiproliferative activity of test compounds was measured by sulforhodamine-B (SRB) assay.ResultsEugenol exhibited noticeable antioxidant potential in DPPH radical scavenging (81 %) and reducing power (1.12) assays at 1.0 μM/ml and 0.1 μM/ml concentrations, respectively. IC50 value of eugenol for radical scavenging activity was found to be 0.495 μM/ml. Cinnamaldehyde demonstrated considerable metal ion chelating ability (75 %) at 50 μM/ml and moderate lipo-protective activity in lipid peroxidation assay at 3 μM/ml. In addition cinnamaldehyde also showed appreciable antibacterial activity (zone of inhibition 32–42 mm) against Bacillus cereus (MTCC 6840), Streptococcus mutans (MTCC 497), Proteus vulgaris (MTCC 7299), Salmonella typhi (MTCC 3917) and Bordetella bronchiseptica (MTCC 6838) while eugenol produced moderate activity at 80 μM/disc. Cinnamaldehyde exhibited comparatively better antiproliferative potential against breast (T47D) and lung (NCI-H322) cancer cell lines than eugenol in SRB assay at 50 μM concentration.ConclusionCinnamaldehyde possessed metal ion chelating, lipo-protective, antibacterial and antiproliferative activities while eugenol showed potent H-atom donating potential indicating radical quenching and reducing power abilities. Medicinal attributes shown by both the compounds indicated their usefulness in food and pharmaceutical sector.

Several Classes of Natural Products with Metal ion Chelating Ability

Several Classes of Natural Products with Metal ion Chelating Ability

Chelating properties of salicylhydroxamic acid-functionalized polystyrene resins and its application to efficient removal of heavy metal ions from aqueous solutions

Salicylhydroxamic acid(SHA) was covalently bound onto crosslinked polystyrene spheres(CPSs) via the Friedel-Crafts alkylation reaction between chloromethylated CPSs and SHA in the presence of SnCl4 as the Lewis acid catalyst. The resulted SHA-CPSs possessed very strong chelating ability for heavy metal ions. In particular, the saturated adsorption amount of SHA-CPSs for Cu2+ ions could reach as high as 34.2 mg/g at 318 K. The chelating capability of SHA-CPSs towards heavy metal ions was pH and temperature dependent. SHA-CPSs also showed selective metal coordination with the chelating capacity decreasing in the order of Cu2+ >Zn2+>>Pb2+. The adsorption isotherms conformed well to the Langmuir model, and the adsorption process was found to be entropy-driven and endothermic. Besides, SHA-CPSs possessed the excellent reusability.

Preliminary Evaluation of Biological Activities and Phytochemical Analysis of Syngonium podophyllum Leaf

Present study reports the phytochemical profiling, antimicrobial, antioxidant, and anticancer activities of Syngonium podophyllum leaf ethyl acetate extract. Dried leaf samples were extracted with ethyl acetate by using soxhlet apparatus. Phytochemical screening revealed the presence of flavonoids, terpenoids, reducing sugars, alkaloids and saponins. Total phenolic and flavonoid contents in extracts were 3.67 ± 0.02 mg propyl galate equivalent and 3.23 ± 0.02 mg quercetin equivalents per gram of sample, respectively. At different concentrations reducing ability of the leaf extract was in the range of 0.170–0.350. The extract accounted for moderate DPPH radical scavenging potential (50 %) and metal ion chelating ability (55 %) at higher concentrations. Test extract provided about 30–36 % protection against peroxidation of membrane lipids in rat tissue homogenate. The extract exhibited 43 % growth inhibition against lung cancer (NCI-H322) and 53 % against breast cancer (T47D) cell lines. In disc diffusion assay extract demonstrated considerable antibacterial activity (ZOI 12–15 mm) against Bacillus cereus (MTCC 6840), Streptococcus mutans (MTCC 497), Proteus vulgaris (MTCC 7299), Salmonella typhi (MTCC 3917), and Bordetella bronchiseptica (MTCC 6838) in comparison with standard antibiotics (ZOI 15–16 mm). The study revealed moderate antioxidant, anticancer and considerable antibacterial activities in S. podophyllum leaf ethyl acetate extract.

Synthesis and Characterization of Bisdithiocarbamates from Weak Nitrogen Bases and Its Metal Complexes

In the present study, disodium salts of bisdithiocarbamates have been prepared from urea, thiourea, dithiooxamide and 1,3 - diaminopropanewith carbon disulfide under strong alkaline medium of a sodium hydroxide solution . All ligands possessed good chelating ability for various metal ions. Metal complexes of urea bisdithiocarbamates was synthesized with Co (II), Ni (II), Zn (II), and Pb(II). The nature of metal complexes was amorphous and solid. The prepared ligan ds and complexes were characterized by elemental analysis, electronic, infrared (IR) spectroscopy, conductivity

Study on recognition and separation of rare earth ions at picometre scale by using efficient ion-surface imprinted polymer materials

The graft-polymerization of hydroxyethyl methylacrylate (HEMA) on micro-sized silica gel particles was first conducted by initiating of a surface-initiating system, which was constituted by the bonded amino groups on the modified silica gel particles and persulfate in the solution, obtaining the grafted particles PHEMA/SiO2 with a high grafting degree of 40g/100g. Subsequently, 8-hydroxyquinoline as a ligand with strong chelating ability for metal ions was bonded on the side chains of the grafted macromolecule PHEMA through the substitution reaction between 5-chloromethyl-8-hydroxyquinoline (CHQ) and the hydroxyl group of the grafted macromolecule PHEMA, preparing the functional grafted particles HQ-PHEMA/SiO2. On the basis of examining the chelating adsorption property of HQ-PHEMA/SiO2 particles for Pr3+ ion, the Pr3+ ion surface-imprinting was carried out by using the effective surface-imprinting technique of “pre-grafting and post-crosslinking/imprinting” established by our group. During the surface-imprinting process, Pr3+ ion was used as a template ion, and 2,2′-dichlorodiethyl ether was used crosslinked, resulting in the Pr3+ ion surface-imprinted material IIP-HQP/SiO2. The recognition and binding characters of IIP-HQP/SiO2 towards Pr3+ ion were investigated in-depth with La3+ and Ce3+ ions as two contrast ions. The experimental results show that the IIP-HQP/SiO2 particles possess special recognition selectivity and high binding ability for Pr3+ ion. The binding capacity of IIP-HQP/SiO2 for Pr3+ ion reaches 0.13mmol/g, and relative to La3+ and Ce3+ ions, the selectivity coefficients of IIP-HQP/SiO2 for Pr3+ ion are 5.22 and 5.12, respectively. La, Ce and Pr are three neighbouring rare earth elements, and the ion radius differences between La3+, Ce3+ and Pr3+ ions are only in a range of 2–5pm. Obviously, in this investigation, the mutual separation of La3+, Ce3+ and Pr3+ ions at picometre scale is realized successfully by using the ion surface-imprinted polymer material with high performance.

Synthesis Characterization and Spectral Studies of Bisdithiocarbamate of Urea and its Metal Complexes

A novel disodium salt of Bisdithiocarbamates of urea (UBDT) and its metal complexes, Co(II)UBDT, Ni(II)UBDT, Cu(II)UBDT and Cd(II)UBDT were prepared and characterized by Elemental Analysis, Conductivity Measurements, Infrared Spectroscopy, Electronic Spectroscopy and NMR Spectroscopy. Water-soluble UBDT possessed good chelating ability for various metal ions. Its complexes, Co (II), Ni (II), Cu (II) and Cd (II) are amorphous, intractable solid having polymeric structure. The ligand as well as the complex was found to possess high thermal stability.

In vitro antioxidant, antibacterial, and cytotoxic activity and in vivo effect of Syngonium podophyllum and Eichhornia crassipes leaf extracts on isoniazid induced oxidative stress and hepatic markers.

The present study reports the in vitro antioxidant, antibacterial, and cytotoxic potential of Syngonium podophyllum (SP) and Eichhornia crassipes (EC) leaf aqueous extracts as well as their in vivo effect on oxidative stress and hepatic biomarkers in isoniazid induced rats. Phytochemical screening of extracts revealed the presence of flavonoids, terpenoids, reducing sugars, alkaloids, and saponins. Phenolic content in SP and EC extracts was 5.36 ± 0.32 and 10.63 ± 0.13 mg PGE/g, respectively, while flavonoid content was 1.26 ± 0.03 and 0.51 ± 0.03 μg QE/mg, respectively. EC extract exhibited comparatively better antioxidant activity as indicated by reducing power (0.197–0.775), DPPH radical scavenging potential (11%–96%), and metal ion chelating ability (42%–93%). Both the extracts provided 13%–65% protection against lipid peroxidation in rat tissue (liver, kidney, and brain) homogenate. SP and EC extracts exhibited 51% and 43% cytotoxicity against lung cancer (NCI-H322) cell line, respectively. Both extracts demonstrated considerable antibacterial activity against Proteus vulgaris, Salmonella typhi, and Bordetella bronchiseptica. Coadministration of E. crassipes extract with isoniazid in rats accounted for 46% decrease in malondialdehyde content and 21% increase in FRAP value of plasma. It also mitigated the isoniazid induced alterations in serum enzymes (SGOT, SGPT, and ALP), total bilirubin, creatinine, and hemoglobin contents. S. podophyllum extract was found to be hepatotoxic.

The Study of Chitosan-Citrate Solution as a Root Canal Irrigant: A Preliminary Report

Objective: Citric acid has been reported removal of smear layer, low antibacterial property, low cytotoxicity. Although the citric acid alone has few used as a root canal irrigant, citric acid formulation with antibacterial effect such as MTAD and Tetraclean has already produced. However, these formulations tended to produce bacteria resistant to antibiotics such as tetracycline and others.Chitosan have been reported broad spectrum of antibacterial properties, high chelating ability for various metal ions in acidic conditions, biocompatibility and biodegradability. Therefore, we focused on citric acid as a solution to dissolve chitosan. The purpose of this study was to determine whether chitosan-citrate solution shows antibacterial properties against Enterococcus faecalis and removes the smear layer when used as a root canal irrigant.Methods: E. faecalis (4532D) was incubated in brain-heart infusion broth. Chitosan-citrate solution was then added to the bacterial inoculum for 5, 15, 30, and 60 min. Survival rates of E. faecalis were statistically analyzed using one-way repeated measures ANOVA and Tukey test. Extracted teeth were used for this experiment. The middle third of the root was cut longitudinally, and all specimens were immersed in chitosan-citrate solution until an antibacterial effect was obtained. All specimens were examined under scanning electron microscopy. The number of open dentin tubules was determined for evaluation of smear layer removal. One-way repeated measures ANOVA and Tukey test were used for analysis of open dentin tubules.Results: The antibacterial effect of chitosan-citrate solution was achieved at 5 min. Furthermore, chitosan-citrate solution resulted in a significantly greater reduction of the survival rate than 10% citric acid after 5 min of application (p<0.01). The smear layer was also removed after immersion in chitosan-citrate solution for 5 min. Chitosan-citrate solution removed significantly more of the smear layer than 10% citric acid (P<0.05).Conclusion: In conclusion, chitosan-citrate solution showed antibacterial activity and enabled removal of smear layer. As this ability depended on chitosan, it is considered that the action was enhanced by chitosan. Chitosancitrate solution has been indicated as a possible root canal irrigant.