Isolation, Characterization, Antioxidant, and Wound Healing Activities of Extracellular Polysaccharide from Endophytic Fungus Talaromyces purpureogenus.

In this study, two extracellular polysaccharides (TEPS1 and TEPS2) were isolated from the endophytic fungus (Talaromyces purpureogenus) and purified by DEAE-Sepharose Fast Flow column using NaCl as gradient eluent. The HPLC analysis displayed that TEPS1 was composed of mannose (38.70%), ribose (25.02%), glucose (19.34%), and galactose (16.94%) while the TEPS2 composed by mannose (100%). The NMR results indicated that TEPS1 exhibited α-glycosidic configurations. The both polysaccharides, TEPS1 and TEPS2 were exhibited a good antioxidant activity in terms of DPPH, ABTS, and •OH scavenging. However, TEPS1 showed a higher antioxidant activity than TEPS2. The IC50 of TEPS1 were 32.16, 192.57, and 54.67 µg·mL-1, for DPPH, ABTS, and •OH radical scavenging, respectively. Furthermore, TEPS1 showed the high cellular antioxidant and wound healing activity in the human embryonic kidney (HEK293) cell line. Overall, these two polysaccharides were promising in antioxidant activity.

Polysaccharides of Weissella cibaria Act as a Prebiotic to Enhance the Probiotic Potential of Lactobacillus rhamnosus.

This work aimed to investigate the effect of EPS (extracellular polysaccharide) of Weissella cibaria as a prebiotic to promote the growth and antibacterial properties of Lactobacillus rhamnosus. The morphological, growth behavior, and antibacterial properties of L. rhamnosus were determined in MRSB (de Man Rogosa Sharpe broth) supplemented with different concentrations of EPS (0.1-2%). The results revealed that the incorporation of the EPS (2%) in MRSA improved the bacterial growth in terms of colony-forming unit (CFU, 0.7 × 105 CFU/mL) compared to L. rhamnosus grown in bare MRSA. The SEM observation revealed that EPS incorporation in the MRSB culture media does not affect the morphological properties of L. rhamnosus. Moreover, it was confirmed that the extract of probiotics cultured in MRSA supplemented with EPS (2%) was exhibited strong antibacterial and antibiofilm activity against targeted pathogens. This L. rhamnosus extract was found to be biocompatible evidanced by erythrocyte hemolysis assay. These results confirmed that EPS regulates the growth of probiotics, resists pathogen infection, and biocompatibility.

Combination of Paraconiothyrium brasiliense fabricated titanium dioxide nanoparticle and antibiotics enhanced antibacterial and antibiofilm properties: A toxicity evaluation.

Antimicrobial resistance (AMR) causes global consequences through increased mortality and economic loss. Antimicrobial drugs including nanomaterials are an emerging environmental impact. Hence, this work aimed to synthesize and characterize the titanium dioxide nanoparticles (TiO2 NPs) using the aqueous extract of endophytic fungus Paraconiothyrium brasiliense (Pb) for enhancing the antibacterial efficiency of existing standard antibiotics at minimum concentration. The FTIR and XRD results confirmed the capping of functional molecules and the crystalline nature of Pb-TiO2 NPs. The spherical-shaped TiO2 NPs with the size of 57.39 ± 13.65 nm were found in TEM analysis. The average hydrodynamic size (68.43 ± 1.49 d. nm) and the zeta potential (-19.6 ± 1.49 mV) was confirmed the stability of Pb-TiO2 NPs. Antibacterial studies revealed that bare Pb-TiO2 NPs (20 µg/mL) did not exhibit significant antibacterial activity while combination of TCH + Pb-TiO2 NPs considerably increased the inhibition of E. coli biofilm evidenced by CLSM and SEM analysis. Further, Pb-TiO2 NPs (100 µg/mL) were found to be moderately toxic to cell line (NIH3T3), red blood cells (RBC), and egg embryos. Hence, this study concluded that <50 µg/mL of TiO2 NPs can be mixed with antibiotics for enhanced antibacterial application thereby minimizing the AMR and the environmental toxicity.

Synthesis, characterization, and cytotoxicity of starch-encapsulated biogenic silver nanoparticle and its improved anti-bacterial activity.

The present work reported synthesis, characterization, and biocompatibility of starch encapsulated silver nanoparticles (St-PF-AgNPs) and their antibacterial activity. The synthesis of St-PF-AgNPs involved in two steps: (i) synthesis of the biogenic silver nanoparticles using the fungal extracts (PF-AgNPs); and, (ii) encapsulation of starch in PF-AgNPs (St-PF-AgNPs). The surface plasmon resonance was found at 420 nm for the PF-AgNPs while it was at 260 and 420 nm for the St-PF-AgNPs. FTIR spectrum demonstrated the capping and encapsulation of the fungal extracts and starch in PF-AgNPs and St-PF-AgNPs. The XRD and TEM-EDS confirmed the crystalline nature, spherical-shaped , and polydispersed- PF-AgNPs and St-PF-AgNPs with strong signals of Ag. The St-PF-AgNPs showed a Z-average size of 115.2 d.nm and zeta potential of -17.8 (mV) as indicated by DLS and zeta potentials. The cytotoxicity results demonstrated higher toxicity of PF-AgNPs than St-PF-AgNPs in HEK293 cells. The antibacterial activity of St-PF-AgNPs were higher than PF-AgNPs in S. aureus. Overall, this work concluded that the starch encapsulation significantly increased the antibacterial activity of PF-AgNPs and this opens a new avenue for the treatment of bacterial infections through the sustained release of PF-AgNPs to target pathogenic bacterial cells.