ZnCl2 Research Articles

Physicochemical Characterization of Simplicia Sambiloto (Andrographis paniculata) Powder with Types and Concentrations of Reagents in the Formation of Zn-Chlorophyll Complexes

During the process of making sambiloto simplicial which involves heat, it can cause degradation of chlorophyll. Increasing the stability of chlorophyll can be done by forming Zn-chlorophyll complexes with metals which are be able to form complexes where more stable than Mg such as by using Zn. The aim of this research is to determine how the physical and chemical characteristics of the bitter simplicia powder produced are influenced by the type of reagent and the concentration of the reagent when heated in an oven. Simplicia bitter powder is made through a sorting, grinding and sieving process. Next, the zinc chloride and zinc acetate reagents were mixed with concentrations of 0, 200, 300, 400, and 500 ppm, and then dried. The results showed a real effect (p value <0.05) of the interaction between the types of ZnCl2 and Zn acetate reagents and the reagent concentration on color intensity, color stability, water content, ash content and chlorophyll content. The higher the concentration of ZnCl2 and Zn acetate, the higher the water content, ash content, chlorophyll content, L*, and -a*, while b* and ∆E decrease. At a concentration of 500 ppm ZnCl2 showed an increase in water, ash, chlorophyll, ∆E, L*, and a* content while b* decreased. Meanwhile, Zn acetate 500 ppm moisture content, ash content, chlorophyll content, L*, and ∆E decreased, while a* and b* increased. Sambiloto simplicia powder which has the highest chlorophyll content is Zn acetate 400 ppm, with characteristics of water content 6.81% ww, ash content 15.74% ww, total chlorophyll 397.97 mg/100 g ww, green color intensity (-a) -2.93, and ∆E 5.48.

1- and 2-Tetrazolylacetonitrile as Versatile Ligands for Laser Ignitable Energetic Coordination Compounds.

1- and 2-Tetrazolylacetonitrile (1- and 2-TAN) have been synthesized by the reaction of chloroacetonitrile with 1H-tetrazole under basic conditions. They further were reacted with sodium azide in the presence of zinc(II) chloride to form 5-((1H-tetrazol-1-yl)methyl)-1H-tetrazole (1-HTMT) and 5-((2H-tetrazol-2-yl)methyl)-1H-tetrazole (2-HTMT). The nitrogen-rich compounds have been applied as ligands for Energetic Coordination Compounds (ECCs) and show interesting coordinative behavior due to different bridging modes. The structural variability of the compounds has been proved by low-temperature X-ray analysis. The ECCs were analyzed for their sensitivities to provide information about the safety of handling and their capability to serve as primary explosives in detonator setups to replace the commonly used lead styphnate and azide. All colored ECCs were evaluated for their ignitability by laser initiation in translucent polycarbonate primer caps. In addition, the spin-crossover characteristics of [Fe(1-TAN)6](ClO4)2 were highlighted by the measurement of the temperature-dependent susceptibility curve.

A green chemistry approach for preparation of metronidazole-zinc (ІІ) complexes: In vitro characterization, antimicrobial activity and promising cytotoxicity

Antibiotic-metal complexes attract the attention of pharmaceutical scientists who endeavor to increase the activity of antibiotics currently in use as those looking for new compounds possessing modified pharmacological and toxicological properties. This research proposed enhanced antimicrobial and cytotoxic activities of metronidazole and reduced irritancy of zinc chloride through complexation. The chemically green preparation of metronidazole: zinc (ІІ) complexes with different ratios: (A; 2:1), (B; 1:1) and (C; 1:2), revealed the formation of three complexes. The differences between their structures, physical and chemical properties were evaluated using morphological characteristics, DSC, XRD, FTIR, Mass spectrometry, and UV–Vis spectroscopy. The antimicrobial activities of the complexes were increased when compared to the parent drug where complex-C manifested the highest antibacterial activity (MIC = 0.625 mM and 10 mM for the bacterial strains and C. albicans, respectively). The antitumor efficacy of the complexes was studied against HepG2 and MCF-7 human cancer cell lines. Complex-A showed the highest cytotoxicity against HepG2 cells (IC50 = 17.2 μM), while, complex-C displayed the most cytotoxic activity against MCF-7 cells (IC50 = 29.0 μM). The in vivo skin irritancy study of the complexes on rats and their histological examination were assessed and showed no erythema and/or edema. Our results suggest the promising antimicrobial and antitumor activity of the prepared metronidazole-zinc complexes.

Construction of Bimetallic-Anchored Two-Dimensional Nanosheets on COF for Rechargeable Zinc-Air Batteries.

The preparation of carbon materials by doping bimetallic oxides into triazine frameworks (COFs) is a promising electrocatalyst with the potential to replace precious metals in energy storage systems. In this experiment, a covalent triazine framework (COF) was synthesized by 1,4-dicyanobenzene (DCB) and zinc chloride, in which the COF and transition metals were used as carbon, nitrogen, cobalt, and iron sources. According to the properties of this COF, the destruction of the catalyst during pyrolysis can be prevented. The enhanced catalytic performance of the catalysts can be seen by testing all of the samples of catalysts in an alkaline medium. The high half-wave potential (E1/2) of 0.86 V is comparable to Pt/C and also shows excellent durability by testing. Zinc-air batteries were assembled using the prepared catalysts, and the batteries were tested for specific capacity (548 mAh g-1) and power density (189 mW cm-2). This work provides a new direction for COF-derived catalysts for carbon materials.

Facile synthesis of N-doped biomass derived porous carbon from Opuntia humifusa using simple solid state activation method for reversible capture of volatile iodine

The search for adsorbent materials capable of extracting and storing radioactive iodine derived from nuclear power plants has intensified owing to the growing nuclear waste concerns. Herein, we report a novel method, which is simple and effective, to synthesize biomass-derived porous carbon from an easily available biomass, Opuntia humifusa, via simple solid-state activation with zinc chloride. The resulting porous carbon exhibits a large specific surface area, with up to 1869 m2/g of micropores. The textural properties of activated carbons can be easily modified by adjusting the amount of zinc chloride and activation temperature. The optimal conditions were found to be a ZnCl2 to biomass ratio of 5 and a carbonization temperature of 500 °C. The obtained porous carbons can function as multifunctional solid sorbents for radioactive iodine because of their high porosity and advantageous hierarchical porous structure. Specifically, the obtained activated carbon exhibited high iodine affinity with an absorption of 408 wt%. Considering its global abundance and recyclability, Opuntia humifusa can be used as a new biomass source for the efficient production of highly effective porous carbon materials with potential applications in environmental restoration. Furthermore, the straightforward single-step synthesis method described in this study offers a technique for producing several unique activated mesoporous carbons from various biomasses.

Abstract 5750: Development of prostate specific membrane antigen-targeted liposomal zinc for the treatment of prostate cancer

Abstract Introduction: Treatment choices for early-stage prostate cancer include mostly watchful waiting, radical prostatectomy, or radiation therapy, whereas for advanced cases hormone therapy followed by chemo/radiotherapy are the preferred options, despite their notable side effects. There is a need for more effective therapy with lower side effects, especially for advanced scenarios. Unlike normal epithelial prostate cells, cancerous ones show reduced zinc (Zn) levels due to ZIP1 zinc transporter downregulation. Zn deficiency allows m-aconitase to remain active, making prostate cancer cells energy efficient and grow. High levels of Zn are needed to inhibit m-aconitase, the enzyme responsible for the first reaction in the Krebs cycle. This study aims to induce energy starvation and cell death of prostate cancer cells by inhibiting m-aconitase using the prostate-specific membrane antigen (PSMA)-targeting liposomal zinc. Methods: Liposomes were prepared by standard reverse phase evaporation method with DSPC, Cholesterol and DSPE-mPEG(2000) lipids. Zinc chloride was used to load Zn+2 into liposome following passive loading method. PSMA-expressing (PC3-PIP) and PSMA-null (PC3-LUC) human prostate cancer cells were used for in vitro studies. In the cell uptake study, cells were incubated with Dil-dye labeled liposomes for 2 hours before analyzing them by microscopy and flow cytometry. For the uptake inhibition study, cells were pre-incubated with PSMA-specific peptide for 2 hours before incubation with liposomes. Cytotoxicity studies were performed with PSMA-targeting Zn-loaded liposomes in PC3-PIP cells. Results: We conjugated the PSMA-specific peptide and control peptide (ASP3) with DSPE-PEG(3400)-NHS, and used them at various amounts (1 to 4 mol% of total lipid) to prepare Zn-loaded PSMA-targeting liposomes (TL) and control liposomes (CL), respectively. The average hydrodynamic diameter of all the liposomes was 120 to 130 nm, and zeta potential ranged from -16 to -12 mV. The encapsulation efficiency and loading capacity of Zn+2 were 0.6% and 8.5%, respectively. Cellular uptake studies showed a higher accumulation of PSMA-targeting liposome (TL) compared to non-targeting liposome (CL) in PSMA-expressing PC3 cells, whereas both liposomes showed low uptake in PSMA non-expressing cell. Furthermore, pre-treatment of PSMA-expressing cells with PSMA-specific peptide reduced the uptake of TL, indicating that the uptake of TL liposome is PSMA dependent. Finally, cytotoxicity studies showed that Zn-loaded TL, induces cell death in the PSMA-expressing cells. Overall, we developed PSMA-targeting Zn-containing liposomes that selectively target and kill PSMA-expressing prostate cancer cells. Future work includes testing the effect of Zn-loaded TL on m-aconitase activity and testing of in vivo efficacy of the formulation in prostate cancer models. Citation Format: Sujan K. Mondal, Alexander L. Klibanov, Anna Moore. Development of prostate specific membrane antigen-targeted liposomal zinc for the treatment of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5750.

A Facile Zinc(II) Chloride Assisted Desulfurization of High‐Nitrogen Heterocycles

AbstractHigh‐nitrogen heterocycles are important to fields as diverse as pharmaceuticals and energetic materials. However, their synthesis can often be inconvenient or involve toxic precursors. In this work, we synthesize 1‐substituted‐5H‐tetrazoles via the desulfurization of readily available 1‐substituted‐1H‐tetrazole‐5‐thiones via a zinc chloride assisted desulfurization providing a new, safe, and efficient process with higher yields than the traditional desulfurization methods.

Syntheses, Crystal Structures and Antimicrobial Activity of Zinc(II) Complexes Derived from 5-Bromo-2- (((2-piperazin-1-yl)ethyl)imino)methyl)phenol

Three new zinc(II) complexes, [ZnCl2L]·CH3OH (1), [ZnClL(NCS)]·2CH3OH·0.5H2O (2), and [ZnL(NCS)2]·CH3OH·H2O (3), where L is the zwitterionic form of 5-bromo-2-(((2-piperazin-1-yl)ethyl)imino)methyl)phenol, NCS is thiocyanate anion, were facile prepared by reaction of different molar ratio of L, zinc chloride and ammonium thiocyanate in methanol. The complexes were characterized by IR and UV-Vis spectroscopy. Detailed structures of the three complexes were confirmed by single crystal X-ray determination. The Zn atoms in the complexes are in tetrahedral coordination. The Schiff base ligand coordinates to Zn atom through phenolate oxygen atom and amino and imino nitrogen atoms. The remaining two sites are occupied by two Cl for 1, one Cl and one NCS for 2, and two NCS for 3. The compounds show significant antimicrobial activities.

Removal of bentazone using activated carbon from spent coffee grounds

AbstractBACKGROUNDThis study aimed to produce activated carbon (AC) from spent coffee (Coffea arabica) grounds by chemical activation using zinc chloride (ZnCl2) and nitric acid to remove bentazone from aqueous solutions.RESULTSThe fresh spent coffee grounds were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and the AC by X‐ray diffraction (XRD), infrared spectroscopy (FTIR), Brunauer–Emmett– Teller (BET), point of zero charge, scanning electron microscopy (SEM) and the Boehman method. Adsorption experiments were carried out in a batch system. The results showed a 70% efficiency in bentazone removal using ZnCl2 carbon. Kinetic studies indicate that the adsorption rate increased slowly up to 720 min; the first‐ and second‐order models fitted the experimental data at a concentration of 50 mg L−1. The adsorption equilibrium is represented by the Langmuir model with a high adsorption capacity of 279.33 ± 6.29 mg mg−1. The adsorption efficiency was also confirmed by toxicity analysis of the effluent with bentazone at 50 mg L−1, using the Allium cepa bioassay, a high‐sensitivity test for pollutants in water.CONCLUSIONBefore adsorption, the effluent caused significant cytogenotoxicity to onion root meristems. After adsorption, the generated effluent no longer caused toxicity to the test system, and the results obtained were similar to the control with distilled water. © 2024 Society of Chemical Industry (SCI).

Oral Rinses: Some Kill and Some Cripple Candida albicans

Introduction: Oral healthcare professionals play a crucial role in guiding patients toward evidence-based choices among the many available oral rinses. In this study, we explored how specific oral rinse formulations affect the viability and modulate critical virulence traits of the opportunistic fungal pathogen Candida albicans. Materials and Methods: We assessed the effects of these oral rinses on the production of germ tube, production of phospholipase and hemolysin, as well as biofilm formation. Results: We found that oral rinses containing cetylpyridinium chloride (CPC) and chlorhexidine (CHX) showed the greatest fungicidal activity with the lowest minimum fungicidal concentrations (0.38% and 0.78%, respectively). Oral rinses based on zinc chloride and sodium fluoride with Miswak bark extract (MIS) or essential oils (EO) had much lower fungicidal activity (8–16 times lower) compared to CHX and CPC. However, they had a significantly greater impact on the virulence traits of C. albicans. They reduced germ tube production by 86–89% (vs. 42% for CHX and 29% for CPC), completely inhibited phospholipase and hemolysin production, and together with the CPC-based oral rinse, exerted the greatest reductions in biofilm formation across all tested concentrations. This was in contrast to both the controls and CHX, which had a minimal effect on biofilm formation. Conclusion: By inhibiting the virulence factors, the oral rinse can have a crippling effect on C. albicans, weakening this opportunistic pathogen and hindering its potential to cause infection.

O-Trifluoromethylation of Carboxylic Acids via the Formation and Activation of Acyloxy(phenyl)trifluoromethyl-λ3-Iodanes.

Here we report the challenging O-trifluoromethylation of carboxylic acids via the formation and activation of acyloxy(phenyl)trifluoromethyl-λ3-iodanes. The method provides an easy access to various potentially valuable and hitherto elusive trifluoromethyl carboxylic esters. A remarkably wide range of substrates with commonly encountered functional groups are compatible with this reaction, including aromatic and aliphatic carboxylic acids, as well as Food and Drug Administration (FDA) approved drugs and pharmaceutically relevant molecules. The reaction mechanism and the origins of the enhanced reactivity by zinc chloride (ZnCl2) were discussed from experimental evidence and density functional theory (DFT) calculation.

O‐Trifluoromethylation of Carboxylic Acids via the Formation and Activation of Acyloxy(phenyl)trifluoromethyl‐λ3‐Iodanes

AbstractHere we report the challenging O‐trifluoromethylation of carboxylic acids via the formation and activation of acyloxy(phenyl)trifluoromethyl‐λ3‐iodanes. The method provides an easy access to various potentially valuable and hitherto elusive trifluoromethyl carboxylic esters. A remarkably wide range of substrates with commonly encountered functional groups are compatible with this reaction, including aromatic and aliphatic carboxylic acids, as well as Food and Drug Administration (FDA) approved drugs and pharmaceutically relevant molecules. The reaction mechanism and the origins of the enhanced reactivity by zinc chloride (ZnCl2) were discussed from experimental evidence and density functional theory (DFT) calculation.

“Exploring the Inhibitory Potential of Acetoxime-Zinc Chloride Adduct in Saline Environments for Mild Steel Corrosion Protection”

ABSTRACT In this work, acetoxime, zinc chloride and acetoxime adduct of zinc chloride, [ZnCl2.2{HON=C(CH3)2}] (ZA) were investigated as corrosion inhibitor's in 3.5%NaCl solution on mild steel. The electrochemical analysis was carried out using polarization measurements and electrochemical impedance technique and surface analysis was done by Scanning electron microscope coupled with Energy-dispersive X-ray spectroscopy. Using surface analysis and electrochemical data it was concluded that an inhibition synergy was developed when ZA was taken instead of acetoxime or zinc chloride alone in solution phase. Scanning electron microscope methods were used to examine the samples surface in the presence of inhibited solutions. The efficiency of inhibition increases with the increasing concentration and attained the values of 97.18% for the 3mM concentration of ZA.

Synthesis of sustainable mesoporous sulfur-doped biobased carbon with superior performance sodium diclofenac removal: Kinetic, equilibrium, thermodynamic and mechanism

Over the last years, the strategy of employing inevitable organic waste and residue streams to produce valuable and greener materials for a wide range of applications has been proven an efficient and suitable approach. In this research, sulfur-doped porous biochar was produced through a single-step pyrolysis of birch waste tree in the presence of zinc chloride as chemical activator. The sulfur doping process led to a remarkable impact on the biochar structure. Moreover, it was shown that sulfur doping also had an important impact on sodium diclofenac (S-DCF) removal from aqueous solutions due to the introduction of S-functionalities on biochar surface. The adsorption experiments suggested that General and Liu models offered the best fit for the kinetic and equilibrium studies, respectively. The results showed that the kinetic was faster for the S-doped biochar while the maximum adsorption capacity values at 318 K were 564 mg g−1 (non-doped) and 693 mg g−1 (S-doped); highlighting the better affinity of S-doped biochar for the S-DCF molecule compared to non-doped biochar. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) suggested that the S-DCF removal on both adsorbents was spontaneous, favourable, and endothermic.

Docking, Synthesis and Evaluation of 4-hydroxy-1-phenyl-2(1H)-quinolone Derivatives as Anticancer Agents.

The estimated number of cancer cases in India for the year 2022 was found to be 14,61,427. The development of chemotherapeutic agents has reduced the mortality rate, however, they have high toxicity which is a disadvantage. Many researchers have found out that quinolin-2- one possesses anticancer activity, with this background we thought of synthesizing the quinolin-2-one derivatives. This study aimed to carry out docking, synthesis, characterization, and evaluation of 2-(2- (4-Hydroxy-2-oxoquinolin-1(2H)-yl)phenyl/ substituted phenyl)-3-(phenylamino) thiazolidon-4-one derivatives (IVa-g) as an anticancer agent. Diphenylamine and malonic acid treated with phosphoryl chloride gave compound I, which on formylation afforded compound II, which on reaction with various substituted aromatic phenylhydrazine derivatives gave compounds IIIa-g, which on further reaction with thioglycolic acid and anhydrous zinc chloride yielded the compounds IVa-g. Among all the synthesized novel derivatives, compounds IV a-d showed 50% lysis in the IC50 range of 25-50μg for the A549 cell line, and compounds IVa, and IVb showed 50% lysis in the IC50 range of 25-50μg for the MDA-MB cell line. The compound, 3-((4-fluorophenyl)amino)-2-(2-(4- hydroxy-2-oxoquinolin-1(2H)-yl)phenyl)thiazolidin-4-one (IVg) was found to be the most active against both the cell line, A549 and MDA-MB with IC50 value of 0.0298μmol and 0.0338μmol respectively. The docking results revealed that the synthesized compounds exhibited well-conserved hydrogen bonding with one or more amino acid residues in the active pocket of EGFR tyrosine kinase domain with 4-anilinoquinazoline inhibitor erlotinib (PDB ID:1M17). Compound IVg showed the highest MolDock score of -137.813 compared to the standard drug Imatinib having a MolDock score of -119.354. Compound IVg showed the highest MolDock score and was also found to be most potent against both the cell line, A549, and MDA-MB.

Quantitative proteome and lysine succinylome characterization of zinc chloride smoke-induced lung injury in mice

The inhalation of zinc chloride (ZnCl2) smoke is one of common resources of lung injury, potentially resulting in severe pulmonary complications and even mortality. The influence of ZnCl2 smoke on lysine succinylation (Ksucc) in the lungs remains uncertain. In this study, we used a ZnCl2 smoke inhalation mouse model to perform global proteomic and lysine succinylome analyses. A total of 6781 Ksucc sites were identified in the lungs, with injured lungs demonstrating a reduction to approximately 2000 Ksucc sites, and 91 proteins exhibiting at least five differences in the number of Ksucc sites. Quantitative analysis revealed variations in expression of 384 proteins and 749 Ksucc sites. The analysis of protein-protein interactions was conducted for proteins displaying differential expression and differentially expressed lysine succinylation. Notably, proteins with altered Ksucc exhibited increased connectivity compared with that in differentially expressed proteins. Beyond metabolic pathways, these highly connected proteins were also involved in lung injury-associated pathological reactions, including processes such as focal adhesion, adherens junction, and complement and coagulation cascades. Collectively, our findings contribute to the understanding of the molecular mechanisms underlaying ZnCl2 smoke-induced lung injury with a specific emphasis on lysine succinylation. These findings could pave the way for targeted interventions and therapeutic strategies to mitigate severe pulmonary complications and mortality associated with such injuries in humans.

Effects of Tetrabasic Zinc Chloride on the Diarrhea Rate, Intestinal Morphology, Immune Indices and Microflora of Weaned Piglets.

This study was aimed to investigate the effects of different dietary zinc sources on the diarrhea rate, intestinal morphology, immune indexes and intestinal microbial composition of weaned piglets. A total of 240 weaned piglets (Duroc × Landrace × Yorkshire), at the age of 21 days, were randomly assigned to five dietary treatments for a four-week feeding trial to determine the effects of different amounts of tetrabasic zinc chloride (TBZC) supplementation on intestinal morphology, intestinal immune indices and intestinal microflora in weaned piglets, compared with the pharmacological dose of ZnO. The dietary treatments included a negative control (CON), (T1) ZnO (ZnO, 1500 mg/kg), (T2) tetrabasic zinc chloride (TBZC, 800 mg/kg), (T3) tetrabasic zinc chloride (TBZC, 1000 mg/kg), and (T4) tetrabasic zinc chloride (TBZC, 1200 mg/kg). Each treatment comprised six replicate pens, with eight pigs (four barrows and four gilts) per pen. Dietary TBZC of 1200 mg/kg improved the duodenum villus height, jejunum villus height and crypt depth of ileum, and increased the ratio of villus height to crypt depth of ileum (p < 0.05). The dietary supplementation of TBZC at a dosage of 1200 mg/kg has the potential to increase the levels of immunoglobulin G (IgG) and immunoglobulin A (IgA) in the duodenal mucosa. Furthermore, it shows a significant increase in the levels of immunoglobulin A (IgA) in the ileum. Compared with CON, TBZC significantly (p < 0.05) decreased pH values of stomach contents. It also increased the number of Firmicutes in intestinal contents. Compared with CON, the abundance of Firmicutes in jejunum contents of other treatments was significantly improved (p < 0.05), while the abundance of Proteobacteria in ileum contents of high-zinc treatments (T2 and T5) was decreased (p < 0.05). In conclusion, dietary TBZC of 1200 mg/kg improved the digestibility of crude protein in weaned piglets, altered the intestinal morphology of piglets, changed the intestinal microflora of piglets, reduced the diarrhea rate, and significantly improved the development of the small intestine of weaned piglets, and its regulation mechanism on intestinal tract needs further study. In summary, TBZC is likely to be an effective substitute source for the pharmacological dose of ZnO to control diarrhea in weaned piglets.

Low formaldehyde-emission particleboards with the addition of Scots pine wood waste derived activated carbon

ABSTRACT Free formaldehyde released after particleboard production poses significant risks to human and environmental health. This study investigated the impact of adding activated carbon produced from pine wood waste to particleboard on formaldehyde emissions to lessen this risk. In the first stage of the study, pine wood waste was activated with zinc chloride (ZnCl2) at 600°C for 90 min to produce activated carbon. The activated carbon was examined by scanning electron microscope, thermogravimetric analysis, Brunauer–Emmett–Teller (BET) analysis, fourier-transform infrared spectroscopy and X-ray diffraction. BET surface area of the produced activated carbon was 1102 m2/g. In the second stage of the study, activated carbons (0.5%, 1.0% and 1.5%) were added to a commercially preferred three-layer particleboard to enhance its mechanical, thermal and physical properties. In addition, the effects of the activated carbon on the free formaldehyde emissions of particleboard at 0 and 6 months were investigated. It was found that the free formaldehyde emissions of particleboards with activated carbon addition decreased by 24% at 0 months- and 6 months by 27% compared to the control group. Thus, waste material that has become a more valuable product as activated carbon will minimize harm to the environment and humans.

Zinc Chloride as a Catalyst in Hydrothermal Carbonization of Cocoa Pods Husk

In this study, we have successfully synthesized a high surface area of activated carbons (ACs) from cocoa pod husk (CPH) by using a combination of hydrothermal carbonization (HTC) and chemical activation in the presence of ZnCl2 as both of catalyst as well as activating agent. During HTC, the effect of HTC temperature (200 and 225 °C) and ZnCl2 to biomass mass ratio (1:1, 2:1, 3:1) as a catalyst to the characteristics of the obtained hydrochar (HC) and ACs were investigated. The obtained hydrochar (HCs) was then processed by using ZnCl2 chemical activation with a fixed HC to ZnCl2 mass ratio of 1:4 and the mixture was pyrolyzed at 600 °C for 1 h under an inert atmosphere. The results showed that the addition of catalyst during HTC presented different AC morphology, where the carbon samples were decorated with carbon microspheres. An increase of surface area was observed, where the ACs synthesized from catalyzed HC at biomass to ZnCl2 ratio of 1:3 at temperature 200 °C gave a higher surface area of 1954 m2/g compared to that of without catalyst (1165 m2/g). The catalysis effect was more profound at the HTC temperature of 200 °C compared to 225 °C, as reflected in the significant increase of AC surface area. The addition of a catalyst creates ACs with narrow pore distribution compared to that of synthesized in the absence of a catalyst. It was also observed that the ACs from catalyzed hydrochar possessed higher oxygenated functional groups (OFG) than those without catalysts.

Effects of Zinc Compounds on the Enzymatic Activities of Lysozyme and Peroxidase and Their Antifungal Activities

This study aimed to investigate the effects of zinc compounds on the enzymatic activities of lysozyme, peroxidase, and the glucose oxidase–mediated peroxidase (GO-PO) system and their antifungal activities. Four different zinc compounds (zinc chloride, gluconate, lactate, and sulfate) were incubated with hen egg-white lysozyme (HEWL), bovine lactoperoxidase (bLPO), the GO-PO system, and human unstimulated whole saliva in solution and on a hydroxyapatite surface. Enzymatic activities of lysozyme, peroxidase, and the GO-PO system were measured through the hydrolysis of Micrococcus lysodeikticus, oxidation of fluorogenic 2′,7′-dichlorofluorescin, and glucose assay, respectively. Interactions between zinc and enzymes were analyzed by surface plasmon resonance (SPR). The minimum inhibitory concentration (MIC) and candidacidal activities of zinc compounds were examined against three Candida albicans strains. Zinc gluconate and sulfate significantly increased the enzymatic activities of salivary lysozyme in the solution assay and of HEWL and salivary lysozyme on the hydroxyapatite surface. However, all examined zinc compounds significantly decreased the enzymatic activities of bLPO and salivary peroxidase in solution and on the surface. SPR analyses revealed binding of zinc to lysozyme and peroxidase, with affinity differing according to the zinc compounds. The MIC of zinc compounds against C. albicans was 1.0–2.4 mM. Candidacidal activities were 17.7–38.8% and 23.7–47.0% at 1.0 and 10 mM concentrations, respectively. In conclusion, zinc compounds enhanced lysozyme activity but inhibited peroxidase activity. Zinc compounds exhibited concentration-dependent candidacidal activity against C. albicans. Zinc compounds are potential therapeutic agents for oral health, especially for geriatric patients.