Background: The severe acute respiratory syndrome (SARS) is a life threatening viral infection caused by a positive, single stranded RNA virus from the enveloped coronaviruse family. Associated with fever, cough, and respiratory complications, the illness causes more than 15% mortality worldwide. So far, there is no remedy for the illness except supportive treatments. However, the main viral proteinase has recently been regarded as a suitable target for drug design against SARS infection due to its vital role in polyproteins processing necessary for coronavirus reproduction. Objectives: The present in silico study was designed to evaluate the effects of anti HIV-1 proteases inhibitors, approved for clinical applications by US FDA, on SARS proteinase inhibition. Methods: In the present study, docking and molecular dynamic experiments were applied to examine the effect of inhibitors on coronavirus proteinase under physiological conditions of similar pH, temperature, and pressure in aqueous solution. Hex software version 5.1 and GROMACS 4.5.5 were used for docking analysis throughout this work. Results:The calculated parameters such as RMSD, RMSF, MSD, dipole moment, diffusion coefficient, binding energy, and binding site similarity indicated effective binding of inhibitors to SARS proteinase resulting in their structural changes, which coincide with proteinase inhibition. Conclusions:The inhibitory potency of HIV 1 protease inhibitors to cronovirus proteinase was as follows: LPV > RTV > APV > TPV > SQV. Lopinavir and Saquinavir were the most and the least powerful inhibitors of cronovirus proteinase, respectively.

Band assignment for oxy, deoxy and methemoglobin using orbital promotion is crucial to understanding inter-relation of electronic transitions. Spectral changes may be correlated with conformational alteratiions. Conformational changes of hemoglobin were interpreted using four-orbital model of Gouterman. Our results indicated that Goutherman model can predict the predominant conformations of hemoglobin.

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In the present study, the effects of administrating 4 mM and 300 mg kg(-1) b.wt. of quinolinic acid were studied, in vitro and in vivo, respectively, to evaluate its inhibitory activity on phosphoenolpyruvate carboxykinase in diabetic rats. The results of in vitro studies have clearly indicated the inhibitory effect of quinolinic acid on enzyme activity. The hill plot showed the binding stoichiometry of quinolinic acid per enzyme to be 4:1. The in vivo studies showed that intra peritoneal injection of 300 mg kg(-1) b.wt. initiates reduction of blood glucose level in 1 h after injection, restoring the blood glucose to its normal level at 2 h post injection and keeping it constant for at least further 4 h. Based on present results we concluded that quinolinic acid and hence its precursor tryptophan having induced obvious hypoglycemic effects in normal and diabetic rats at high enough concentrations, they are worthy of further study and research for their hyperglycemic effect in other diabetic animal models.

Objective: To evaluate the efficacy of some medicinal plants and systemic glucantime in a comparative manner against the causative agent of cutaneous leishmaniasis both in vitro and in BALB/c mice. Methods: For in vivo testing, inbred mice were challenged with Leishmania major parasites and the resultant ulcers were treated with extract based-ointments applied topically two times per day for a period of 20 days. A group of 56 mice were randomly divided into 7 subgroups. The control group received the ointment void of extracts, whereas the reference group received glucantime only. The efficacy of treatments was evaluated by measuring ulcer diameter, parasite burden and NO production. Results: Our results indicated that plant extract based-ointments were effective in reducing ulcer size and parasite burden in spleens, but their effects did not differ significantly from that of glucantime. The plant extracts tested in this study were able to increase NO production that helped parasite suppression. Conclusions:Our findings indicate that the tested plant extracts are effective against Leishmania major both during in vitro and in vivo experiments, but further researches are required to recommend a potential plant extract as an alternative drug.