In Silico Evaluation for the Inhibitory Action of Curcumin Derivatives on the SARS-CoV-2 Proteins

Purpose of the Study: COVID-19 is caused by the SARS-CoV-2 virus that had a global pandemic spread in the last two years. Symptoms of the disease include respiratory distress and, in severe cases may consequently lead to death. Blocking the viral proteins can aid in treating this disease and alleviating its symptoms. Two target proteins of the coronavirus that are hot spots in drug discovery are the papain-like protease PL-pro and the main protease M-pro. PL-pro is an enzyme that is required for processing viral polyproteins to generate a functional replicase complex and enable viral spread. M-pro is the major protease of SARS-CoV-2, which is a keystone in viral replication and transcription. Methods: In this study, we shed the light on the route of targeting viral proteins for disease alleviation, by targeting the two aforementioned enzymes, PL-pro and M-pro using in silico studies. Docking experiments, using AutoDock algorithms, were performed to predict the inhibitory effect of recently produced synthetic derivatives of curcumin on the viral proteins. Results: Most of the curcumin derivatives have shown variable levels of inhibition, e.g., S1 - S6, mainly on the papain-like protease, and to a lesser extent on the main protease. Conclusion: The results indicated that curcumin derivatives can be potent anti-viral drug of SARS-CoV-2, namely targeting the papain-like protease.

Identification of Novel and Potent Curcuminoids Inhibitors of Tubulin with Anticancer Activities by 3D-QSAR and Molecular Docking

The three-dimensional quantitative structure-activity relationships(3D-QSAR)for 37 curcumin derivatives were constructed by CoMFA and CoMSIA methods,respectively.The results showed that the cross validated coefficient(q^2)and non-cross-validated coefficient(R^2)were 0.711,0.962 in CoMFA model and 0.774,0.856 in CoMSIA model,respectively,which suggests that two models are robust and have good exterior predictive capabilities.Based on these two models and the binding mode with tubulin,nine novel curcuminoids inhibitors which could exhibit much higher anticancer potency and efficiently occupy the colchicine binding site of tubulin,were designed.We expect that the results in this paper have the potential to facilitate the process of design and to develop new potent curcumin derivatives with stronger anticancer activities.

C0818,a novel curcumin derivative,interacts with Hsp90 and inhibits Hsp90 ATPase activity

The aims of the present study were to estimate the affinity between 3,5-(E)-bis(3-methoxy-4-hydroxybenzal)-4-piperidinone hydrochloride(C0818) and heat shock protein 90 (Hsp90) and to investigate the inhibitory effects of this compound on Hsp90 ATPase activity. Fluorescence spectroscopy was used to examine the affinity between varying concentrations of C0818 and Hsp90, N-Hsp90, MHsp90 and C-Hsp90. Fluorescence intensities were recorded in the range of 290–510 nm at 293, 303 and 310 K, respectively. A colorimetric assay for inorganic phosphate(based on the formation of a phosphomolybdate complex and the subsequent reaction with malachite green) were used to examine the inhibitory effects of C0818 on Hsp90 ATPase activity. The equilibrium dissociation constant K_D value of C0818 was found to be 23.41270.943 μmol/L. The interaction between C0818 and Hsp90 was driven mainly by electrostatic interactions. C0818 showed the strongest affinity with C-Hsp90. These results conclusively demonstrate the inhibitory activity of C0818 on the activity of Hsp90 ATPase.