Exploring ethynyl-based chalcones as green semiconductor materials for optical limiting interests.

The fabrication of molecular electronics from non-toxic functional materials which eventually would potentially able to degrade or being breaking down into safe by-products have attracted much interests in recent years. Hence, in this study, the introduction of mixed highly functional substructures of chalcone (-CO-CH=CH-) and ethynylated (C≡C) as building blocks has shown ideal performance as solution-processed thin film candidatures. Two types of derivatives, (MM-3a) and (MM-3b) repectively, showed a substantial Stokes shifts at 75 nm and 116 nm, in which such emission exhibits an intramolecular charge transfer (ICT) state and fluoresce characteristics. The density functional theory (DFT) simulation shows that MM-3a and MM-3b exhibit low energy gaps of 3.70 eV and 2.81 eV, respectively. TD-DFT computations for molecular electrostatic potential (MEP) and frontier molecular orbitals (FMO) were also used to emphasise the structure-property relationship. A solution-processed thin film with a single layer of ITO/PEDOT:PSS/MM-3a-MM-3b/Au exhibited electroluminescence behaviour with orange and purple emissions when supplied with direct current (DC) voltages. To promote the safer application of the derivatives formed, ethynylated chalcone materials underwent toxicity studies toward Acanthamoeba sp. to determine their suitability as non-toxic molecules prior to the determination as safer materials in optical limiting interests. From the preliminary test, no IC50 value was obtained for both compounds via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay analysis and molecular docking analysis between MM-3a and MM-3b, with profilin protein exhibited weak bond interactions and attaining huge interaction distances.

Synthesis, anti-amoebic activity and molecular docking simulation of eugenol derivatives against Acanthamoeba sp.

Amoebae of the genus Acanthamoeba can cause diseases such as amoebic keratitis and granulomatous amoebic encephalitis. Until now, treatment options for these diseases have not been fully effective and have several drawbacks. Therefore, research into new drugs is needed for more effective treatment of Acanthamoeba infections. Eugenol, a phenolic aromatic compound mainly derived from cloves, has a variety of pharmaceutical properties. In this study, nine eugenol derivatives (K1-K9), consisting of five new and four known compounds, were synthesized and screened for their antiamoebic properties against Acanthamoeba sp. The structure of these compounds was characterized spectroscopically by Fourier transform infrared (FTIR), Ultraviolet-Visible (UV-Vis), 1H and 13C Nuclear Magnetic Resonance (NMR) and mass spectrometer (MS). The derived molecules were screened for antiamoebic activity by determining IC50 values based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and observation of amoeba morphological changes by light and fluorescence microscopy. Most of the tested compounds possessed strong to moderate cytotoxic effects against trophozoite cells with IC50 values ranging from 0.61 to 24.83 µg/mL. Observation of amoebae morphology by light microscopy showed that the compounds caused the transformed cells to be roundish and reduced in size. Furthermore, fluorescence microscopy observation using acridine orange (AO) and propidium iodide (PI) (AO/PI) staining showed that the cells have damaged membranes by displaying a green cytoplasm with orange-stained lysosomes. Acidification of the lysosomal structure indicated disruption of the internal structure of Acanthamoeba cells when treated with eugenol derivatives. The observed biological results were also confirmed by interaction simulations based on molecular docking between eugenol derivatives and Acanthamoeba profilin. These interactions could affect the actin-binding ability of the protein, disrupting the shape and mobility of Acanthamoeba. The overall results of this study demonstrate that eugenol derivatives can be considered as potential drugs against infections caused by Acanthamoeba.

Combinatorial treatment with ß-glucanase enzyme and chlorhexidine induces cysticidal effects in Acanthamoeba cyst.

Acanthamoeba cysts have a cellulose cell wall made up of a solid layer of ß-glucan, which confers resistance to the dormant phase of this microorganism. The ability of Acanthamoeba to change to this dormant phase causes difficulties in treating its infection at the cyst stage as compared to the trophozoite stage. Therefore, targeting cyst total mortality can help to prevent re-infection in patients. To ensure cysticidal treatment, a ß-glucanase enzyme was introduced in vitro to the Acanthamoeba cyst, followed by a chlorhexidine solution treatment. ß-glucanase enzyme and chlorhexidine dose-response analysis was performed based on cell wall integrity measurement. The treatment was also performed on human corneal epithelial cells to confirm the safety of the treatment in vitro. The surface morphology of the cysts was observed using scanning electron microscopy (SEM), while the protein alterations were determined using 1D protein analysis. The interaction of the ß-glucanase enzyme with cellulose linkages was investigated based on molecular dosimetry. Incubation of the cyst for 24 h at 8.75 units/ml of ß-glucanase followed by 0.88 µg/ml of chlorhexidine resulted in a substantial reduction in the total chlorhexidine used, which made it safer for human corneal epithelial cells. Ultrastructural changes revealed the reduction of the thickness in ectocyst and endocyst layers with the loss of the internal structure of the cyst. After combination treatment of chlorhexidine and ß-glucanase, a decrease in the cyst protein from the size of 37 to 25 kDa was observed. The enzyme-substrate interaction validated these results based on molecular docking between 1,4-ß-D-glucan and 1,4- ß-D-xylan with the ß-glucanase enzyme. In silico analysis revealed that two catalytic glutamate residues (Glu160 and Glu267) are essential to catalysing the hydrolytic reaction. Molecular dynamic simulation analysis revealed that both ligands formed stable interactions throughout the simulation. This work concludes that the enzymatic approach combined with chlorhexidine is a novel and effective technique for ensuring the cysticidal effects against the Acanthamoeba cyst. The interaction of the chlorhexidine and ß-glucanase enzyme on the surface of the cyst of amoeba resulted in the ecto-and endo cyst layer being damaged and confirmed the cysticidal effects.

Biomedical PEVA Nanocomposite with Dual Clay Nanofiller: Cytotoxicity, Mechanical Properties, and Biostability.

Poly(ethylene-vinyl acetate) (PEVA) nanocomposite incorporating dual clay nanofiller (DCN) of surface modified montmorillonite (S-MMT) and bentonite (Bent) was studied for biomedical applications. In order to overcome agglomeration of the DCN, the S-MMT and Bent were subjected to a physical treatment prior to being mixed with the copolymer to form nanocomposite material. The S-MMT and Bent were physically treated to become S-MMT(P) and Bent(pH-s), respectively, that could be more readily dispersed in the copolymer matrix due to increments in their basal spacing and loosening of their tactoid structure. The biocompatibility of both nanofillers was assessed through a fibroblast cell cytotoxicity assay. The mechanical properties of the neat PEVA, PEVA nanocomposites, and PEVA-DCN nanocomposites were evaluated using a tensile test for determining the best S-MMT(P):Bent(pH-s) ratio. The results were supported by morphological studies by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Biostability evaluation of the samples was conducted by comparing the ambient tensile test data with the in vitro tensile test data (after being immersed in simulated body fluid at 37 °C for 3 months). The results were supported by surface degradation analysis. Our results indicate that the cytotoxicity level of both nanofillers reduced upon the physical treatment process, making them safe to be used in low concentration as dual nanofillers in the PEVA-DCN nanocomposite. The results of tensile testing, SEM, and TEM proved that the ratio of 4:1 (S-MMT(P):Bent(pH-s)) provides a greater enhancement in the mechanical properties of the PEVA matrix. The biostability assessment indicated that the PEVA-DCN nanocomposite can achieve much better retention in tensile strength after being subjected to the simulated physiological fluid for 3 months with less surface degradation effect. These findings signify the potential of the S-MMT(P)/Bent(pH-s) as a reinforcing DCN, with simultaneous function as biostabilizing agent to the PEVA copolymer for implant application.

Design, synthesis and antiamoebic activity of dysprosium-based nanoparticles using contact lenses as carriers against Acanthamoeba sp.

PURPOSE: Contact lenses have direct contact with the corneal surface and can induce sight-threatening infection of the cornea known as Acanthamoeba keratitis. The objective of this study was to evaluate the dysprosium-based nanoparticles (Dy-based NPs), namely Fe3 O4 -PEG-Dy2 O3 nanocomposites and Dy(OH)3 nanorods, as an active component against Acanthamoeba sp., as well as the possibility of their loading onto contact lenses as the drug administering vehicle to treat Acanthamoeba keratitis (AK). METHODS: The Dy-based NPs were synthesized, and they were loaded onto commercial contact lenses. The loading content of the NPs and their release kinetics was determined based on the absorbance of their colloidal solution before and after soaking the contact lenses. The cytotoxicity of the NPs was evaluated, and the IC50 values of their antiamoebic activity against Acanthamoeba sp. were determined by MTT colorimetric assay, followed by observation on the morphological changes by using light microscopy. The mechanism of action of the Dy-based NPs against Acanthamoeba sp. was evaluated by DNA laddering assays. RESULTS: The loading efficiencies of the Dy-based NPs onto the contact lens were in the range of 30.6-36.1% with respect to their initial concentration (0.5 mg ml-1 ). The Dy NPs were released with the flux approximately 5.5-11 µg cm-2  hr-1 , and the release was completed within 10 hr. The emission of the NPs consistently showed a peak at 575 nm due to Dy3+ ion, offering the possible monitoring and tracking of the NPs. The SEM images indicated the NPs are aggregated on the surface of the contact lenses. The DNA ladder assay suggested that the cells underwent DNA fragmentation, and the cell death was due most probably to necrosis, rather than apoptosis. The cytotoxicity assay of Acanthamoeba sp. suggested that Fe3 O4 -PEG, Fe3 O4 -PEG-Dy2 O3 , Dy(NO3 )3 .6H2 O and Dy(OH)3 NPs have an antiamoebic activity with the IC50 value being 4.5, 5.0, 9.5 and 22.5 µg ml-1 , respectively. CONCLUSIONS: Overall findings in this study suggested that the Dy-based NPs can be considered as active antiamoebic agents and possess the potential as drugs against Acanthamoeba sp. The NPs could be loaded onto the contact lenses; thus, they can be potentially utilized to treat Acanthamoeba keratitis (AK).

Synthesis, Molecular Docking and Biological Activity Evaluation of Alkoxy Substituted Chalcone Derivatives: Potential Apoptosis Inducing Agent on MCF-7 Cells.

INTRODUCTION: In this contribution, a series of alkoxy substituted chalcones were successfully designed, synthesized, spectroscopically characterized and evaluated for their cytotoxicity potential in inhibiting the growth of MCF-7 cells. OBJECTIVE: In order to investigate the influence between electron density in conjugated π-systems and biological activities, different withdrawing substituents, namely Nitro (NO2), Cyano (C≡N) and trifluoromethyl (CF3) were introduced in the chalcone-based molecular system. METHODS: All the derivatives were then tested on MCF-7 cell line using the fluorescence microscopy-based cytotoxicity analyses. RESULTS: The preliminary findings showed that both -NO2 and -CF3 substituents revealed their potential to inhibit the growth of MCF-7 with IC;50 values of 14.75 and 13.75 µg/ml, respectively. In addition, the morphological changes of MCF-7 cells were observed in response to alkoxy substituted chalcone treatment through an induction of apoptosis pathway with cell blebbing, phosphatidylserine exposure and autophagic activity with acidification of lysosomal structure. Intermolecular interaction based on in silico investigation on nitro, trifluoromethyl and cyano based chalcones exhibited several types of interactions with tumor necrosis factor receptor (PDB: 1EXT) protein and high hydrogen bond in the molecule-receptor interaction have given significant impact towards their toxicity on MCF-7 cells. CONCLUSION: Significantly, these types of chalcones exhibited ideal and high potential to be further developed as anti-cancer agents.

Phytochemicals, mineral contents, antioxidants, and antimicrobial activities of propolis produced by Brunei stingless bees Geniotrigona thoracica, Heterotrigona itama, and Tetrigona binghami.

The present study focused on the evaluation of phytochemical properties, essential mineral elements, and heavy metals contained in raw propolis produced by stingless bees Geniotrigona thoracica, Heterotrigona itama, and Tetrigona binghami found in the same ecological conditions and environment in Brunei Darussalam. The results indicated that propolis of the three stingless bee species mainly consisted of lipids (45.60-47.86%) and very low carbohydrate (0.17-0.48%) and protein contents (0.18-1.18%). The propolis was rich in mineral elements, thus good sources of minerals, while they contained low concentrations of all heavy metals. Propolis of the different bee species could be distinguished based on their mineral compositions. The vibrational and absorption spectra suggested that propolis contains π-conjugated aliphatic and aromatic compounds as well as aromatic acids having amine, ester, carbonyl, alkyl, and hydroxyl functional groups which might be attributed to the presence of phenolic and flavonoid compounds. The antioxidant capacity of the propolis, based on radical scavenging activity of their ethanol extract, was in line with their total phenolic content. The ethanol extract of the propolis also showed antimicrobial activities against four bacterial strains (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa). The propolis showed slightly higher antibacterial activity against Gram-positive (B. subtilis and S. aureus) bacteria, indicating that the antimicrobial active compounds could be associated with flavonoids, which were quantified to be approximately comparable in all the propolis.

Corrigendum to "Combinatorial Cytotoxic Effects of Gelam Honey and 5-Fluorouracil against Human Adenocarcinoma Colon Cancer HT-29 Cells In Vitro".

[This corrects the article DOI: 10.1155/2019/3059687.].

Combinatorial Cytotoxic Effects of Gelam Honey and 5-Fluorouracil against Human Adenocarcinoma Colon Cancer HT-29 Cells In Vitro.

Combination of natural products with chemodrugs is becoming a trend in discovering new therapeutics approach for enhancing the cancer treatment process. In the present study, we aimed to investigate the cytotoxic and apoptosis induction of Gelam honey (GH) combined with or without 5-Fluorouracil (5-FU) on HT-29 cells. The cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay to assess cytotoxicity. Morphological changes and apoptosis were determined by the inverted microscope, Annexin V-FITC, and DNA fragmentation via flow cytometric analysis, respectively. Our results demonstrate that combined treatment revealed a remarkable and concentration-dependent cytotoxic effect on HT-29 cells in comparison with GH and 5-FU alone. Flow cytometry analysis showed that early apoptosis event was more pronounced in combined treatment. In addition, compared to 5-FU alone, apoptosis of HT-29 cells treated with combinations of GH and 5-FU demonstrated increasing percentages of fragmented DNA. Our results suggest that GH has a synergistic cytotoxic effect with 5-FU in HT-29 cell lines in vitro. Although the actions of the molecular mechanisms are not yet clear, the results reveal that the combination of GH and 5-FU could have the potential as a therapeutic agent.

Anti-amoebic activity of acyclic and cyclic-samarium complexes on Acanthamoeba.

This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 µg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 µg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of < 10 µg/mL, both the acyclic and cyclic Sm complexes feature a promising potential as cytotoxic agents to fight amoebic infections.

Successful sperm cryopreservation of the brown-marbled grouper, Epinephelus fuscoguttatus using propylene glycol as cryoprotectant.

This study developed the cryopreservation of brown-marbled grouper spermatozoa for practical application. We examined 32 cryodiluents, developed from four types of cryoprotectants [propylene glycol (PG), dimethyl-sulphoxide (Me2SO), dimethyl-acetamide (DMA) and ethylene glycol (EG)] at four concentrations of 5, 10, 15 and 20% in combination with two extenders [Fetal bovine serum (FBS) and artificial seminal plasma (ASP). Cooling rates were examined by adjusting the height of straws (2.5-12.5 cm) from the liquid nitrogen (LN) vapor and cooled for 5 min before immersion into LN. DNA laddering was used to detect DNA damage in cryopreserved sperm. In fertilization trials, 0.5 g of eggs was mixed with cryopreserved sperm stored for 30 days in LN. The best motility of post-thaw sperm was achieved using 15% PG + 85% FBS (76.7 ± 8.8%); 10% PG + 90% FBS was also effective as cryodiluent. Generally, FBS gave better post-thaw motility compared to ASP. The optimum cooling rate was at 17.6 °C min-1 obtained by freezing at the height of 7.5 cm surface of LN. The results obtained showed that cryopreserved sperm of brown-marbled grouper suffered slight DNA fragmentation, which resulted in significantly lower motility. However, the fertilization (90.9 ±â€¯0.5%), hatching (64.5 ±â€¯4.1%) and deformity rates (3.8 ±â€¯0.2%) obtained from cryopreserved sperm showed no significant difference with fresh sperm. These findings show that the developed protocol for cryopreservation of brown-marbled grouper sperm was viable and will be useful for successful breeding and seed production of brown-marbled grouper.

Pre-dispersed organo-montmorillonite (organo-MMT) nanofiller: Morphology, cytocompatibility and impact on flexibility, toughness and biostability of biomedical ethyl vinyl acetate (EVA) copolymer.

Polymer-clay based nanocomposites are among the attractive materials to be applied for various applications, including biomedical. The incorporation of the nano sized clay (nanoclay) into polymer matrices can result in their remarkable improvement in mechanical, thermal and barrier properties as long as the nanofillers are well exfoliated and dispersed throughout the matrix. In this work, exfoliation strategy through pre-dispersing process of the organically modified montmorillonite (organo-MMT) nanofiller was done to obtain ethyl vinyl acetate (EVA) nanocomposite with improved flexibility, toughness, thermal stability and biostability. Our results indicated that the degree of organo-MMT exfoliation affects its cytotoxicity level and the properties of the resulting EVA nanocomposite. The pre-dispersed organo-MMT by ultrasonication in water possesses higher degree of exfoliation as compared to its origin condition and significantly performed reduced cytotoxicity level. Beneficially, this nanofiller also enhanced the EVA flexibility, thermal stability and biostability upon the in vitro exposure. We postulated that these were due to plasticizing effect and enhanced EVA-nanofiller interactions contributing to more stable chemical bonds in the main copolymer chains. Improvement in copolymer flexibility is beneficial for close contact with human soft tissue, while enhancement in toughness and biostability is crucial to extend its life expectancy as insulation material for implantable device.

A novel antiamoebic agent against Acanthamoeba sp.--A causative agent for eye keratitis infection.

The terbium trinitrate.trihydrate.18-crown ether-6, Tb(NO3)3(OH2)3.(18C6) complex has been characterized by elemental analysis, photoluminescence and single X-ray diffraction. The IC50 values were determined based on MTT assay while light and fluorescence microscopy imaging were employed to evaluate the cellular morphological changes. Alkaline comet assay was performed to analyze the DNA damage. The photoluminescence spectrum of the Tb complex excited at 325 nm displayed seven luminescence peaks corresponding to the (5)D4→(7)F(0, 1, 2, 3, 4, 5, 6) transitions. The cytotoxicity and genotoxicity studies indicated that the Tb(NO3)3(OH2)3.(18C6) complex and its salt form as well as the 18C6 molecule have excellent anti-amoebic activity with very low IC50 values are 7, 2.6 and 1.2 µg/mL, respectively, with significant decrease (p<0.05) in Acanthamoeba viability when the concentration was increased from 0 to 30 µg/mL. The mode of cell death in Acanthamoeba cells following treatment with the Tb complex was apoptosis. This is in contrast to the Tb(NO3)3.6H2O salt- and 18C6 molecule-treated Acanthamoeba, which exhibited necrotic type cells. The percentage of DNA damage following treatment with all the compounds at the IC25 values showed high percentage of type 1 with the % nuclei damage are 14.15±2.4; 46.00±4.2; 36.36±2.4; 45.16±0.6%, respectively for untreated, treated with Tb complex, Tb salt and 18C6 molecule. The work features promising potential of Tb(NO3)3(OH2)3.(18C6) complex as anti-amoebic agent, representing a therapeutic option for Acanthamoeba keratitis infection.