ABSTRACT
Fruits of Citrus sinensis L. Osbeck var. Valencia contain hesperidin as a major flavanone glycoside. Hesperidin (H) was isolated from the peels of Valencia orange and formulated as hexosomal nanodispersions (F1) adopting the hot emulsification method. The antimycobacterial activity(anti-TB) was evaluated through a microplate Alamar blue (MABA) assay where F1 showed significant activity with MIC = 0.19 µM. To unravel the potential mechanism of the anti-TB, a molecular docking study of H using the Mycobacterial Dihydrofolate reductase (Mtb. DHFR) enzyme was performed. Hesperidin exhibited significant interactions with Mtb. DHFR active site. Sulforhodamine B assay was applied to evaluate cytotoxic activity against the lung cancer cell line (A-549). F1 showed a cytotoxic effect at IC50= 33 µM. It also has potent antiviral activity against Human Coronavirus 229E with IC50= 258.8 µM utilising crystal violet assay. Peels of Valencia orange could be a source of bioactive metabolites to control significant diseases.
ABSTRACT
Natural polyelectrolytes, including in the form of complexes with colloidal particles, are increasingly used in pharmacy due to the possibility of regulated attachment of medicinal substances and their targeted delivery to the target organ. However, the formation, stability, and molecular-mass characteristics of polyelectrolyte nanodispersions (ND) vary depending on the nature and composition of the medium of their origin. This is due to the lack of standardized approaches to quality control and regulatory documentation for most natural ND. In this paper, we first introduced the isolation, followed by investigations into their physico-chemical properties and bioactivity. Using the dried droplet method, we were able to detect the "coffee ring effect". Fractographic studies of the surface structure of EHA and FA dried samples using SEM showed its heterogeneity and the presence of submicron particles encapsulated in the internal molecular cavities of polyelectrolyte. FTIR spectroscopy revealed the ND chemical structure of benzo-α-pyron and benzo-γ-pyron, consisting of nanoparticles and a branched frame part. The main elements detected by X-ray fluorescence in humic substance extract and fulvic acid include Si, P, S, K, Ca, Mn, Fe, Cu, Zn, whereas Fe is in high concentrations. The UV-spectra and fluorescent radiation demonstrated the possibility of studying the effect of the fulvate chromone structure on its optical properties. It is shown that dilution of the initial solutions of polyelectrolytes 1:10 contributes to the detection of smaller nanoparticles and an increase in the absolute value of the negative ζ-potential as a factor of ND stability. A study of the EHS effect on the SARS-CoV-2 virus infectious titer in the Vero E6 cell showed the effective against virus both in the virucidal scheme (the SI is 11.90-22.43) and treatment/prevention scheme (the SI is 34.85-57.33). We assume that polyelectrolyte ND prevent the binding of the coronavirus spike glycoprotein to the receptor. Taking into account the results obtained, we expect that the developed approach can become unified for the standardization of the ND natural polyelectrolytes complex, which has great prospects for use in pharmacy and medicine as a drug with antiviral activity.
ABSTRACT
PURPOSE: The public fear associated with the novel coronavirus (SARS-CoV-2) pandemic has triggered recently a significant proliferation of supplements touted as potential cures against bacteria and viruses. Colloidal silver has particularly benefited from this rush given its empirically and scientifically documented anti-bacterial and anti-viral actions. The lack of standards in the unregulated supplements industry remains a major roadblock in evaluating the quality and consistency of marketed products or assessing the accuracy of the information provided by manufacturers. This study is the first scientifically rigorous attempt to evaluate commercial silver colloidal products offered for sale on the internet. METHODS: Fourteen of the most popular colloidal silver products purchased from Amazon (www.amazon.com) were evaluated using state-of-the-art analytical techniques widely accepted as gold standards for investigating the properties (size, shape) and the dispersion of silver nanoparticles. RESULTS: Commercial samples were analysed using UV-Vis, FE-SEM and AAS techniques. In general, the Ag concentration was very close to those claimed by the manufacturer. The colorless product shows no absorbance in the UV-Vis analysis. The FESEM and STEM images confirmed the conclusions of the UV-Vis analysis. CONCLUSION: The results of this evaluation show clearly that 70% of the commercial products evaluated contain only ionic silver. Despite the evidence showing that silver nanoparticles are not present, eight of these products are promoted by the manufacturers as 'colloidal silver'. Considering the extensive scientific research showing major differences between silver ionic and silver nanoparticles in terms of mechanisms of action, efficacy and safety, it is clear that this misrepresentation impacts the consumers and must be addressed. This study serves as blueprint for a scientific protocol to be followed by manufacturers for characterizing their silver supplements.