Functional Properties and Molecular Degradation of Schizostachyum Brachycladum Bamboo Cellulose Nanofibre in PLA-Chitosan Bionanocomposites

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.     

Malformin-A1 (MA1) Sensitizes Chemoresistant Ovarian Cancer Cells to Cisplatin-Induced Apoptosis

High-grade epithelial ovarian cancer is a fatal disease in women frequently associated with drug resistance and poor outcomes. We previously demonstrated that a marine-derived compound MalforminA1 (MA1) was cytotoxic for the breast cancer cell line MCF-7. In this study, we aimed to examine the effect of MA1 on human ovarian cancer cells. The potential cytotoxicity of MA1was tested on cisplatin-sensitive (A2780S) and cisplatin-resistant (A2780CP) ovarian cancer cell lines using AlamarBlue assay, Hoechst dye, flow cytometry, Western blot, and RT-qPCR. MA1 had higher cytotoxic activity on A2780S (IC50 = 0.23 µM) and A2780CP (IC50 = 0.34 µM) cell lines when compared to cisplatin (IC50 = 31.4 µM and 76.9 µM, respectively). Flow cytometry analysis confirmed the cytotoxic effect of MA1. The synergistic effect of the two drugs was obvious, since only 13% of A2780S and 7% of A2780CP cells remained alive after 24 h of treatment with both MA1 and cisplatin. Moreover, we examined the expression of bcl2, p53, caspase3/9 genes at RNA and protein levels using RT-qPCR and Western blot, respectively, to figure out the cell death mechanism induced by MA1. A significant down-regulation in bcl2 and p53 genes was observed in treated cells compared to non-treated cells (p < 0.05), suggesting that MA1 may not follow the canonical pathway to induce apoptosis in ovarian cancer cell lines. MalforminA1 showed promising anticancer activity by inducing cytotoxicity in cisplatin-sensitive and cisplatin-resistant cancer cell lines. Interestingly, a synergistic effect was observed when MA1 was combined with cisplatin, leading to it overcoming its resistance to cisplatin.     

Study of Antibacterial and Anticancer Properties of bioAgNPs Synthesized Using Streptomyces sp. PBD-311B and the Application of bioAgNP-CNC/Alg as an Antibacterial Hydrogel Film against P. aeruginosa USM-AR2 and MRSA

Here, we report the extracellular biosynthesis of silver nanoparticles (AgNPs) and determination of their antibacterial and anticancer properties. We also explore the efficacy of bioAgNPs incorporated in cellulose nanocrystals (CNCs) and alginate (Alg) for the formation of an antibacterial hydrogel film. Streptomyces sp. PBD-311B was used for the biosynthesis of AgNPs. The synthesized bioAgNPs were characterized using UV-Vis spectroscopy, TEM, XRD, and FTIR analysis. Then, the bioAgNPs’ antibacterial and anticancer properties were determined using TEMA and cytotoxicity analysis. To form the antibacterial hydrogel film, bioAgNPs were mixed with a CNC and Alg solution and further characterized using FTIR analysis and a disc diffusion test. The average size of the synthesized bioAgNPs is around 69 ± 2 nm with a spherical shape. XRD analysis confirmed the formation of silver nanocrystals. FTIR analysis showed the presence of protein capping at the bioAgNP surface and could be attributed to the extracellular protein binding to bioAgNPs. The MIC value of bioAgNPs against P. aeruginosa USM-AR2 and MRSA was 6.25 mg/mL and 3.13 mg/mL, respectively. In addition, the bioAgNPs displayed cytotoxicity effects against cancer cells (DBTRG-0.5MG and MCF-7) and showed minimal effects against normal cells (SVG-p12 and MCF-10A), conferring selective toxicity. Interestingly, the bioAgNPs still exhibited inhibition activity when incorporated into CNC/Alg, which implies that the hydrogel film has antibacterial properties. It was also found that bioAgNP-CNC/Alg displayed a minimal or slow release of bioAgNPs owing to the intermolecular interaction and the hydrogel’s properties. Overall, bioAgNP-CNC/Alg is a promising antibacterial hydrogel film that showed inhibition against the pathogenic bacteria P. aeruginosa and MRSA and its application can be further evaluated for the inhibition of cancer cells. It showed benefits for surgical resection of a tumor to avoid post-operative wound infection and tumor recurrence at the surgical site.     

Quenching effect of l-tyrosine on peroxyoxalate chemiluminescence of berberine as the fluorophore

The present work deals with the first attempt to study the effect of l-tyrosine on the characteristics of the peroxyoxalate chemiluminescence. Berberine was applied as an efficient fluorophore. The investigated parameters include rise and fall rate constant for the chemiluminescence burst, theoretical and experimental maximum intensity, the time needed to reach maximum intensity and the total light yield emission, which is theoretically evaluated using the pooled intermediate model by a computerized non-linear least-squares curve fitting program (KINFIT). Furthermore, based on the observed quenching effect of tyrosine, the Stern–Volmer plot with K _Q value of 7.7 × 10⁴ M^?1 in the quencher concentration range 4 × 10^?6–5 × 10^?5 M. Moreover, this method is applied to determinate tyrosine in biological samples successfully.     

In-Vitro Screenings for Biological and Antioxidant Activities of Water Extract from Theobroma cacao L. Pod Husk: Potential Utilization in Foods

Increasing production of cocoa (Theobroma cacao L.) leads to a higher environmental burden due to its solid waste generation. Cocoa pod husk, one of the major solid wastes of cocoa production, contains rich bioactive compounds unveiling its valorization potential. With that in mind, our research aimed to explore the biological and antioxidant activities of aqueous extracts from cocoa pod husks. In this present work, cocoa pod husk was extracted using water and subsequentially partitioned using n-hexane, ethyl acetate, and methanol. The antimicrobial investigation revealed that the ethyl acetate solubles were active against the Staphylococcus aureus, Escherichia coli, and Candida albicans, where at a 20% w/v concentration, the inhibition diameters were 6.62 ± 0.10, 6.52 ± 0.02, and 11.72 ± 0.36 mm, respectively. The extracts were found non-toxic proven by brine shrimp lethality tests against Artemia salina with LC₅₀ scores ranging from 74.1 to 19,054.6 μg/mL. The total phenolic content and total flavonoid content were obtained in the range of 47.44 to 570.44 mg/g GAE and 1.96 to 4.34 mg/g QE, respectively. Antioxidant activities of the obtained extracts were revealed by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay with EC₅₀ reached as low as 9.61 μg/mL by the ethyl acetate soluble. Phytochemical screening based on gas chromatography—mass spectroscopy analysis on the sample with the highest antioxidant activities revealed the dominant presence of three phytosterols, namely gamma-sitosterol, stigmasterol, and campesterol.     

ZEOLITE-SUPPORTED CHROMIUM(VI) OXIDE: A MILD,EFFICIENT, AND INEXPENSIVE REAGENT FOR OXIDATIVE DEPROTECTION OF TRIMETHYLSILYL ETHERS UNDER MICROWAVE IRRADIATION

Primary and secondary trimethylsilyl ethers are effeciently converted to the corresponding carbonyl compounds using HZSM-5 zeolite-supported CrO ₃ under microwave irradiation in solventless system.     

Synthesis,Electrical, Electronic and Charge Transport Properties of Poly(aniline‐co‐p‐toluidine)

Copolymers of aniline with p‐toluidine were synthesized for different molar ratios of the respective monomers in acid medium. The electrical conductivity, charge transport and spectral characteristics upon incorporation of p‐toluidine units into the polyaniline backbone were investigated. The electrical conductivity of the copolymers showed frequency dependence which became more prominent with an increase in the number of p‐toluidine units in the polyaniline backbone. A direct relationship between the frequency dependence and electron localization was observed in the copolymers. Electronic spectra showed blue shifts in the π→π*and benzenoid→quinoid transitions revealing a decrease in the extent of conjugation in the copolymers. The protonated forms of the copolymers were soluble in DMSO giving polaron band around 400 nm. The decrease in electrical conductivity was attributed to the greater electron localizations as revealed from the broader ESR signals. Temperature dependence of electrical conductivity showed that charge transport was mainly through variable range hopping though a mixed conduction behavior was observed at higher temperature range.     

Green solid-phase peptide synthesis 4. γ-Valerolactone and N-formylmorpholine as green solvents for solid phase peptide synthesis

Herein, we report the use of γ-valerolactone (GVL) and N-formylmorpholine (NFM) as DMF substitutes in polystyrene based SPPS. The solubility of selected amino acids and coupling reagents were studied in GVL and NFM, followed by their use in the successful synthesis of Aib-enkephalin pentapeptide (H-Tyr-Aib-Aib-Phe-Leu-NH₂) and Aib-ACP decapeptide (H-Val-Gln-Aib-Aib-Ile-Asp-Tyr-Ile-Asn-Gly-NH₂).     

Effervescence-assisted dispersive liquid-liquid microextraction based on deep eutectic solvent for preconcentration and FAAS determination of copper in aqueous samples

A new effervescence-assisted dispersive liquid-liquid microextraction, EA-DLLME, technique was developed for preconcentration and flame atomic absorption spectrometric determination of copper in aqueous samples. Effervescence assistance and DES combination for metal ion extraction was used for the first time. In the presented study, six different effervescence powders were examined to achieve maximum extraction efficiency. In addition, 1,5 diphenyl carbazide was used as complexing agent and DES prepared by mixing choline chloride and phenol was used as extraction solvent. The effect of several parameters such as pH, concentration of complexing agent, composition and volume of DES, amount of THF, composition and amount of effervescent agent were examined. Performed experiments showed that optimum pH was 6.0, the best effervesce powder composition was NaH₂PO₄:Na₂CO₃ with 2 × 10^?3:1 × 10^?3 molar ratio and the amount of effervesce powder was 0.4 g. Under optimum conditions enhancement factor, limit of detection and limit of quantification were calculated as 78, 2.9 and 9.7 μg L^?1, respectively. In addition, to prove precision of the method intra-day relative standard deviations were calculated for 10 and 50 μg L^?1 Cu²⁺ concentrations and found as 2.1% and 1.3%, respectively. The proposed method showed good linearity within the range of 10.0–100 μg L^?1. Finally, proposed method was successfully applied to determination of copper traces in aqueous samples.