S. Prabhu

Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects

Silver nanoparticles are nanoparticles of silver which are in the range of 1 and 100 nm in size. Silver nanoparticles have unique properties which help in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The major methods used for silver nanoparticle synthesis are the physical and chemical methods. The problem with the chemical and physical methods is that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications. In most of the therapeutic applications, it is the antimicrobial property that is being majorly explored, though the anti-inflammatory property has its fair share of applications. Though silver nanoparticles are rampantly used in many medical procedures and devices as well as in various biological fields, they have their drawbacks due to nanotoxicity. This review provides a comprehensive view on the mechanism of action, production, applications in the medical field, and the health and environmental concerns that are allegedly caused due to these nanoparticles. The focus is on effective and efficient synthesis of silver nanoparticles while exploring their various prospective applications besides trying to understand the current scenario in the debates on the toxicity concerns these nanoparticles pose.

Mechanism of protective action of mangiferin on suppression of inflammatory response and lysosomal instability in rat model of myocardial infarction.

Lysosomal instability has been suggested as a major factor in the development of cellular injury during myocardial necrosis through the formation of inflammatory mediators. The present study was designed to investigate the effect of mangiferin on lysosomal hydrolases and TNF‐α production during isoproterenol (ISPH) induced myocardial necrosis in rats. The rats given ISPH (200 mg/kg body weight twice, subcutaneous) for 2 days showed a significant increase in plasma TNF‐α production, serum and heart lysosomal hydrolases activity. ISPH administration to rats resulted in decreased stability of the membranes, which was reflected by the lowered activity of cathepsin‐D and β‐glucuronidase in mitochondrial, nuclear, lysosomal and microsomal fractions. Pretreatment with mangiferin (100 mg/kg body weight, intraperitoneally) for 28 days, significantly prevented the alterations and restored the enzyme activities to near‐normal status. These findings demonstrate that mangiferin could preserve lysosomal integrity through decrease in the inflammatory process and hence establish the cardioprotective effect of mangiferin. Copyright