Novel designed analogues of quercetin against SARS-CoV2:an in-silico pharmacokinetic evaluation, molecular modeling, MD simulations based study

Here we present the design of the series of quercetin analogues and their molecular docking study involving the binding of quercetin and its analogues with SARS-CoV2 3CLpro. The scientific literature shows that quercetin compound has been successfully used against SARS-CoV by inhibiting the replication of virus in respiratory epithelial cell through the inhibition of the SARS-CoV main protease (3CLpro.) It was suggested that the modification at position 3 in quercetin structure may produce potent compounds against SARS-CoV2. A series of quercetin analogues were designed and screened for physicochemical and pharmacokinetics parameters. The activities of selected compounds against SARS-CoV2 were screened by molecular modelling and evaluated that analogues, Q5, Q6 and Q13 have the best docking scores (-8.01 to -8.17 kcal/mol) and also better than quercetin, α-ketoamide and current available inhibitors of the same target. The structure-activity relationship (SAR) study revealed that the introduction of the amino group in a designed molecule was highly promising for increasing the inhibitory activity against SARS-CoV2 3CL pro. Moreover, to check the stability and orientation of selected compounds inside the binding pocket, the molecular dynamic simulations were performed for 100 ns. Results revealed that the designed analogues Q1, Q6 and Q13 having lowest binding energies (-8.0, -8.17 and -8.06 kcal/mol respectively) as well as better physicochemical properties, pharmacokinetics, and toxicity profile show their potential to synthesize and develop as the therapeutic agents against corona virus.Communicated by Ramaswamy H. Sarma.

Beta-cyclodextrin complexes of celecoxib: molecular-modeling, characterization, and dissolution studies

Celecoxib, a specific inhibitor of cycloxygenase-2 (COX-2) is a poorly water-soluble nonsteroidal anti-inflammatory drug with relatively low bioavailability. The effect of beta-cyclodextrin on the aqueous solubility and dissolution rate of celecoxib was investigated. The possibility of molecular arrangement of inclusion complexes of celecoxib and beta-cyclodextrin were studied using molecular modeling and structural designing. The results offer a better correlation in terms of orientation of celecoxib inside the cyclodextrin cavity. Phase-solubility profile indicated that the solubility of celecoxib was significantly increased in the presence of beta-cyclodextrin and was classified as A(L)-type, indicating the 1:1 stoichiometric inclusion complexes. Solid complexes prepared by freeze drying, evaporation, and kneading methods were characterized using differential scanning calorimetry, powder x-ray diffractometry, and scanning electron microscopy. In vitro studies showed that the solubility and dissolution rate of celecoxib were significantly improved by complexation with beta-cyclodextrin with respect to the drug alone. In contrast, freeze-dried complexes showed higher dissolution rate than the other complexes.