Vibrational and electronic spectral analysis of thymol an isomer of carvacrol isolated from Trachyspermum ammi seed: A combined experimental and theoretical study

Lignin Nanoparticles for Enhancing Physicochemical and Antimicrobial Properties of Polybutylene Succinate/Thymol Composite Film for Active Packaging

The natural abundance, polymer stability, biodegradability, and natural antimicrobial properties of lignin open a wide range of potential applications aiming for sustainability. In this work, the effects of 1% (w/w) softwood kraft lignin nanoparticles (SLNPs) on the physicochemical properties of polybutylene succinate (PBS) composite films were investigated. Incorporation of SLNPs into neat PBS enhanced T_d from 354.1 °C to 364.7 °C, determined through TGA, whereas T_g increased from -39.1 °C to -35.7 °C while no significant change was observed in T_m and crystallinity, analyzed through DSC. The tensile strength of neat PBS increased, to 35.6 MPa, when SLNPs were added to it. Oxygen and water vapor permeabilities of PBS with SLNPs decreased equating to enhanced barrier properties. The good interactions among SLNPs, thymol, and PBS matrix, and the high homogeneity of the resultant PBS composite films, were determined through FTIR and FE-SEM analyses. This work revealed that, among the PBS composite films tested, PBS + 1% SLNPs + 10% thymol showed the strongest microbial growth inhibition against Colletotrichum gloeosporioides and Lasiodiplodia theobromae, both in vitro, through a diffusion method assay, and in actual testing on active packaging of mango fruit (cultivar "Nam Dok Mai Si Thong"). SLNPs could be an attractive replacement for synthetic substances for enhancing polymer properties without compromising the biodegradability of the resultant material, and for providing antimicrobial functions for active packaging applications.

Antimicrobial biodegradable film based on corn starch/Satureja khuzestanicaessential oil/Ag-TiO2nanocomposites

Biosynthesis of nanoparticles (NPs) using plant extract is an eco-friendly method, in which natural materials are used and is a simple, non-toxic, and environmentally friendly green synthesis. In this study, corn starch (CS) film containingSatureja khuzestanicaessential oil (SEO) and Ag-TiO₂nanocomposites (size: nearly 30-60 nm) were prepared and its antimicrobial, morphological, physical, and mechanical characteristics were investigated. Ag-TiO₂nanocomposites with different molar percentages were synthesized byS. khuzestanicaextract and based on the best antibacterial results against Gram-negative bacteria (Escherichia coliATCC 25922 andSalmonella typhimuriumATCC 14028) and Gram-positive bacteria (Staphylococcus aureusATCC 25923), were chosen to prepare the films. Four types of biodegradable films were provided: simple CS film, the film incorporated with SEO (essence film), the film incorporated with Ag-TiO₂nanocomposites (nanofilm), and nano/essence film. The scanning electron microscopy (SEM) was employed for investigating the morphology of the films. The combined energy-dispersive x-ray spectroscopy with SEM was applied to analyze the near-surface elements. Physical characteristics of the films containing water vapor permeability (%) and their moisture content, mechanical tests, and antibacterial properties were examined. Antimicrobial evaluation of the films revealed a 3-4 log and 6-7 log (CFU ml^-1) reduction inS. aureusandE. colispecies respectively, compared to the control group. The bio-polymer film incorporated with extracted essential oil ofS. khuzestanicaand Ag-TiO₂nanocomposites are effective to package foods and can delay chemical, physical, and microbial spoilage.

In vitro and In silico Analysis of the Anti-diabetic and Anti-microbial Activity of Cichorium intybus Leaf extracts

OBJECTIVE

To screen the selected phytochemicals against diabetes by docking studies in comparison with experimental analysis.

METHODS

Ethanol crude extract was obtained from the leaves of C.intybus and its chemical compounds were identified using GC- MS. Docking studies were carried out for selected phytochemicals to find the binding affinity and H-bond interaction using Schrodinger suite. Dynamic simulations were carried out for protein-ligand complex up to 50ns using desmond OPLS AA forcefield and α- Amylase and α- Glucosidase assay were carried for the ethanolic extract to infer its inhibition.

RESULTS

Four compounds were chosen for induced fit docking based on the docking score and glide energy obtained from GLIDE-XP docking. The compounds were docked with the protein target human aldose reductase (PDB ID: 2FZD) for checking the anti-diabetic nature. The molecular dynamics simulations were carried out for the most favorable compounds and stability was checked during the simulations. The ethanol extract exhibits significant α-amylase and α-glucosidase inhibitory activities with an IC50 value of 38μg and 88μg dry extract, respectively, and well compared with standard acarbose drug. The antimicrobial activity was also carried out for various extracts (Chloroform, Ethyl acetate, and Ethanol) of the same (C. intybus) screened against four selected human pathogens. Compared to other solvent extracts, ethanol and chloroform extracts show better inhibition and their minimal inhibitory concentration (MIC) value has been calculated.

CONCLUSION

In silico studies and in vitro studies reveals that C. intybus plant compounds have more potent for treating diabetes.

Development and characterization of corn starch/PVA active films incorporated with carvacrol nanoemulsions

An active film was prepared by corn starch (CS), polyvinyl alcohol (PVA) and carvacrol nanoemulsions (CNE). The microstructure and properties of CNE/corn starch/PVA (CNE/CSP) films were characterized and investigated. Scanning electron microscopy (SEM) revealed the uniform distribution of CNE and discontinuity of the film matrix. Fourier transform infrared (FT-IR) and rheological analysis indicated that CNE could weaken molecular interaction of the film matrix. X-ray diffraction (XRD) show that the films are amorphous and CNE has no effect on crystal structure of the films. Incorporation of CNE significantly increased the tensile strength, Young's modulus, elongation at break, barrier (water vapor and ultraviolet), antioxidant and antifungal activity. With the CNE incorporated, the optimal tensile strength, Young's modulus, elongation at break and antioxidant activity of the films can reach 12 MPa, 11 MPa, 133%, 81%, respectively. Minimum water vapor permeability was 3.1 × 10^-12 gd^-1m^-1Pa^-1. Notably, films incorporated with CNE (≥20%) had good DPPH free radical scavenging ability (>50%) when stored up to 6 days. Films with 25% CNE exhibited excellent antifungal activity against Trichoderma sp. and its inhibitory zone was 47 mm. Overall, the CSP films loaded with CNE (>15%) could be used as food packing materials with good antioxidant and antimicrobial activities.

Spectroscopic and structural investigations on modafinil by FT-IR, FT-Raman, NMR, UV-Vis and DFT methods

Chiral sulfoxide based smart drug modafinil were studied experimentally and theoretically. Vibrational spectra were recorded in the mid IR region and electronic spectra were recorded in UV-Visible region. The molecular geometry, vibrational spectra, magnetic spectra and electronic spectra were simulated using Density Functional Theory (DFT) employed with B3LYP/6-311++G(d,p) basis set. The molecular geometry optimization, vibrational frequencies, chemical shifts and solvent effect on electronic properties were reported. The intermolecular interactions have been studied by Hirshfeld surface analysis. There is good agreement was found between calculated and observed values, thereby to confirm the molecular structure of modafinil.