Polyphenols and their nanoformulations as potential antibiofilm agents against multidrug-resistant pathogens.

The emergence of multidrug-resistant (MDR) pathogens is a major problem in the therapeutic management of infectious diseases. Among the bacterial resistance mechanisms is the development of an enveloped protein and polysaccharide-hydrated matrix called a biofilm. Polyphenolics have demonstrated beneficial antibacterial effects. Phenolic compounds mediate their antibiofilm effects via disruption of the bacterial membrane, deprivation of substrate, protein binding, binding to adhesion complex, viral fusion blockage and interactions with eukaryotic DNA. However, these compounds have limitations of chemical instability, low bioavailability, poor water solubility and short half-lives. Nanoformulations offer a promising solution to overcome these challenges by enhancing their antibacterial potential. This review summarizes the antibiofilm role of polyphenolics, their underlying mechanisms and their potential role as resistance-modifying agents.

Bacteria can become more difficult to kill by forming a protective layer called a biofilm. This is a problem because infections caused by these bacteria can be difficult to treat. Polyphenols are a natural compound found in plants. They have shown promise in fighting resistant bacteria by stopping bacteria from forming a biofilm. However, polyphenols have some limitations. These limitations can be overcome by using nanomaterials, which are types of tiny particles. When polyphenols are combined with nanomaterials, they become much better at fighting bacteria. This is a promising solution to treating resistant infections caused by biofilm-forming bacteria.

Phyto-fabrication of ultrafine nanoscale holmium oxide HT-Ho2O3 NPs and their biomedical potential.

In this study holmium oxide nanoparticles (Ho2O3 NPs) are fabricated using Hyphaene thebaica extracts as a bioreductant. The XRD pattern of HT-Ho2O3 NPs (product from phyto-reduction) suggested that the nanoparticles are crystalline with no impurities. Scherrer approximation revealed grain sizes of ∼10 nm. The HR-TEM revealed HT-Ho2O3 NPs possessed a quasi-spherical morphology complemented by SEM and the particle sizes were in the range of 6-12 nm. The infrared spectra revealed characteristic Ho-O bonding at ∼603 cm-1. Raman spectra indicated five main peaks positioned at 156 cm-1, 214 cm-1, 328 cm-1, 379 cm-1 and 607 cm-1. Eg (optical bandgap) was found to be 5.1 eV. PL spectra indicated two major peaks at 415 nm and 607 nm. EDS spectra confirmed the elemental presence of holmium (Ho). Spotty rings were obtained during the SAED measurement which indicated crystallinity of HT-Ho2O3 NPs. The HT-Ho2O3 NPs were further analyzed for their antioxidant, anti-angiogenic and cytotoxic properties. The antioxidant potential was moderate i.e., 43.40 ± 0.96% at 1000 µg mL-1 which decreased in a dose dependent manner. Brine shrimp lethality was highest at 1000 µg mL-1 with the LC50 320.4 µg mL-1. Moderate anti-angiogenic potential was observed using in ova CAM assay. MTT bioassay revealed that the HT-Ho2O3 NPs inhibited the 3T3 cells (IC50 67.9 µg mL-1), however, no significant inhibition was observed against MCF-7 cells. α-Amylase and ß-glucosidase inhibition revealed that the HT-Ho2O3 NPs can be of use in controlling blood glucose levels. Overall, it can be concluded that biosynthesis using aqueous extracts can be a suitable alternative in finding ecofriendly paradigms for the synthesis of nanoparticles. We suggest extended research into the bioreduced Ho2O3 NPs for establishing their biomedical potential and toxicity.