Virucidal Action Against Avian Influenza H5N1 Virus and Immunomodulatory Effects of Nanoformulations Consisting of Mesoporous Silica Nanoparticles Loaded with Natural Prodrugs.

BACKGROUND: Combating infectious diseases caused by influenza virus is a major challenge due to its resistance to available drugs and vaccines, side effects, and cost of treatment. Nanomedicines are being developed to allow targeted delivery of drugs to attack specific cells or viruses. MATERIALS AND METHODS: In this study, mesoporous silica nanoparticles (MSNs) functionalized with amino groups and loaded with natural prodrugs of shikimic acid (SH), quercetin (QR) or both were explored as a novel antiviral nanoformulations targeting the highly pathogenic avian influenza H5N1 virus. Also, the immunomodulatory effects were investigated in vitro tests and anti-inflammatory activity was determined in vivo using the acute carrageenan-induced paw edema rat model. RESULTS: Prodrugs alone or the MSNs displayed weaker antiviral effects as evidenced by virus titers and plaque formation compared to nanoformulations. The MSNs-NH2-SH and MSNs-NH2-SH-QR2 nanoformulations displayed a strong virucidal by inactivating the H5N1 virus. They induced also strong immunomodulatory effects: they inhibited cytokines (TNF-α, IL-1ß) and nitric oxide production by approximately 50% for MSNs-NH2-SH-QR2 (containing both SH and QR). Remarkable anti-inflammatory effects were observed during in vivo tests in an acute carrageenan-induced rat model. CONCLUSION: Our preliminary findings show the potential of nanotechnology for the application of natural prodrug substances to produce a novel safe, effective, and affordable antiviral drug.

Design, synthesis and anticonvulsant activity of new imidazolidindione and imidazole derivatives.

New imidazolidindiones and tetra-substituted imidazole derivatives were designed, synthesized, and evaluated for the anticonvulsant activity through pentylenetetrazole (PTZ)-induced seizures and maximal electroshock (MES) tests using valproate sodium and phenytoin sodium as reference drugs, respectively. Most of the target compounds showed excellent activity against pentylenetetrazole (PTZ)-induced seizures with fair to no-activity against MES. Compounds 3d, 4e, 11b, and 11e showed higher activity (120%) than that of valproate sodium in PTZ model. Almost all compounds showed no neurotoxicity, as indicated by the rotarod test. Estimation of physicochemical properties and pharmacokinetic profiles of the target compounds were studied. The chemical structures of the target compounds were characterized by different spectrometric methods and elemental analysis.

Purification and characterization of a new thermophilic collagenase from Nocardiopsis dassonvillei NRC2aza and its application in wound healing.

A thermostable metallo-collagenase enzyme (150 kDa), recently identified in a newly isolated actinomycestes strain (Nocardiopsis dassonvillei NRC2aza), has been purified from natural source, characterized to have application in wound healing. A simple 3 step purification procedure gave an increase of purity by 6.23 fold with a specific activity of 387.2 U mg-1. The enzyme activity showed stability across a range of pH (7.0-8.5) and temperature (40-55 °C) with optima at pH 8.0 and 60 °C, respectively. Activators include Mg+2, Ca+2, Zn+2, Na+, K+ and Ba+2, while Mn+2, Co+2, Ni+2and Ag+ ions gave partial inhibition. Full inhibition was given by other tested ions and metalloproteinase inhibitors. Broad substrate specificity was demonstrated including activity against a native collagen. The Km and Vmax of the enzyme using azocollagen were 5.5 mg/ml and 1280 U, respectively. The purified collagenase enhanced wound closure in vitro and in vivo and the repair process was dose dependent. Topical application of the purified collagenase (either of 25 or 50 U) to cutaneous wounds significantly accelerated the rate of wound healing and the formation of granulation tissue. Hence, the purified collagenase has a great potential as a therapeutic agent in wound care and collagen related diseases.