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The main goal of this investigation is to conduct a thorough analysis of the physical, chemical, and morphological characteristics of chitosan derived from various forest fungi. Additionally, the study aims to determine the effectiveness of this vegetal chitosan as an antimicrobial agent. In this study, Auricularia auricula-judae , Hericium erinaceus , Pleurotus ostreatus , Tremella fuciformis , and Lentinula edodes were examined. The fungi samples were subjected to a series of rigorous chemical extraction procedures, including demineralization, deproteinization, discoloration, and deacetylation. Subsequently, the chitosan samples were subjected to a comprehensive physicochemical characterization analysis, encompassing Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), degree of deacetylation determination, ash content determination, moisture content determination, and solubility determination. To evaluate the antimicrobial efficacy of the vegetal chitosan samples, two different sampling parameters were employed, namely human hand and banana, to assess their effectiveness in inhibiting microbial growth. Notably, the percentage of chitin and chitosan varied significantly among the distinct fungal species examined. Moreover, EDX spectroscopy confirmed the extraction of chitosan from H. erinaceus , L. edodes , P. ostreatus , and T. fuciformis . The FTIR spectra of all samples revealed a similar absorbance pattern, albeit with varying peak intensities. Furthermore, the XRD patterns for each sample were nearly identical, with the exception of the A. auricula-judae sample, which exhibited sharp peaks at ~37° and ~51°, while the crystallinity index of this same sample was approximately 17% lower than the others. The moisture content results indicated that the L. edodes sample was the least stable, while the P. ostreatus sample was the most stable, in terms of degradation rate. Similarly, the solubility of the samples showed substantial variation among each species, with the H. erinaceus sample displaying the highest solubility among the rest. Lastly, the antimicrobial activity of the chitosan solutions exhibited different efficacies in inhibiting microbial growth of skin microflora and microbes found on the peel of Musa acuminata × balbisiana .

Background: In spite of the great advances in modern medicine in recent decades, medicines of plant origin are still in use for several ailments in different parts of the world. There is always an urge to develop novel, effective and inexpensive antimicrobials. This study was aimed to evaluate the antimicrobial activity and phytochemical composition of the leaf extract of Clematis hirsuta against selected human bacterial and fungal pathogens., Methods: The crude extracts of C. hirsuta leaves were prepared with five different solvents of varying polarity. Agar well diffusion assay on five different species of ATCC organisms, four clinical bacterial isolates, and four clinically isolated fungi were performed. The tube dilution method was used to determine the minimum inhibitory concentrations and the selected extract was subjected to bio-assay-guided fractionation using column chromatography and the active fraction obtained were pooled and GC-MS, FT-IR, and CHN analysis were conducted, and this study is actually bioassay-guided research., Results: A varying patterns of antimicrobial activity against tested microorganism was observed. Acetone extract showed the highest spectrum of activity (17-32mm) in the well diffusion assay against bacteria and 16-23mm in the case of fungi. The MIC ranged from 7.5-60 mg/mL in the case of bacteria and 15-60 mg/mL against fungi. The bioassay-guided column chromatography of the acetone extract followed by GC-MS showed the presence of three major compounds, specifically O-ethylhydroxylamine (43%), 2-ethyl heptanoic acid (20.6%), and 1-nonyl cycloheptane (19.5%). The finding was confirmed by FT-IR and elemental analysis of TLC-separated fractions., Conclusion: The acetone extract showed better antimicrobial activity and the least minimum inhibition concentrations against bacteria compared to fungi. The observed antibacterial can be assigned to the presence of alkoxy amine, alkyl aliphatic acids, and cycloalkane. The overall findings substantiate the traditional usages of the parts of this plant, especially the leaves, in managing infectious diseases., Competing Interests: The authors report no conflicts of interest in relation to this work., (© 2022 Ameya et al.)

Scientists are indeed fascinated by the pharmacologically important chemicals found in medicinal plants. Citrus fruits possess several curing agents for the prevention of diseases. Therefore, experiments were carried out to test the antibacterial activity of methanolic extracts of peels from various locally available citrus fruits such as citron ( Citrus medica ), satkora ( Citrus macroptera ) and adajamir ( Citrus assamensis ) against Bacillus spp. and E. coli using the disc diffusion method. Different physicochemical characteristics of fruit juice were also determined. Methanolic extract of satkora peel had the highest antibacterial activity of 2.2 and 2.6 cm while adajamir had the lowest antibacterial activity of 1.7 and 2.1 cm as ZOI against Bacillus spp. and E. coli , respectively. In the case of pH and total soluble solids (TSS), the three citrus varieties showed a small variation where satkora showed the highest total phenolic content (TPC), vitamin C content, and antioxidant activity than the others. Citrus fruits can be exploited as antibacterial and antioxidant ingredients in food and nutraceuticals, according to the findings of this study., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Ceramic-metal (CaO·Al 2 O 3 -Al and CaO·Al 2 O 3 -Ag) compounds were prepared by mechanical milling and consolidated through an in-situ sintering process. The aim of this work is to study the effects of the Al and Ag particles to ceramic-base compound, primarily in the microstructure, and its mechanical and antimicrobial properties. Chemical systems with a 1:1 M ratio between CaCO 3 and Al 2 O 3 powder were formed, with the addition of 10 wt% Al or 10 wt% Ag, respectively. The compound material that consolidated were microstructurally characterized through X-ray diffraction, scanning electron microscopy, optic microscopy, and X-ray computed tomography. In addition, the hardness, the fracture toughness, the transversal elastic modulus, and the antimicrobial property were evaluated. The results of X-ray diffraction identified the formation of the calcium aluminate phases, such as CaO·6Al 2 O 3 (hibonite:CA6), CaO·2Al 2 O 3 (grossite:CA2), and CaO·Al 2 O 3 (krotite:CA); as well as Al and Ag were identified in its respective system. In addition, the mechanical properties show changes compared to the reference material that was synthesized under the same conditions and, finally, these materials also have an antimicrobial effect, against the Staphylococcus bacterium that is common in the oral cavity, when studied in synthetic saliva., (Copyright © 2019 Elsevier Ltd. All rights reserved.)