RESUMEN

SARS-CoV-2, a new coronavirus emerged in 2019, causing a global healthcare epidemic. Although a variety of drug targets have been identified as potential antiviral therapies, and effective candidate against SARS-CoV-2 remains elusive. One of the most promising targets for combating COVID-19 is SARS-CoV-2 Main protease (Mpro, a protein responsible for viral replication. In this work, an in-house curated library was thoroughly evaluated for druggability against Mpro. We identified four ligands (FG, Q5, P5, and PJ4) as potential inhibitors based on docking scores, predicted binding energies (MMGBSA), in silico ADME, and RMSD trajectory analysis. Among the selected ligands, FG, a natural product from Andrographis nallamalayana, exhibited the highest binding energy of -10.31 kcal/mol close to the docking score of clinical candidates Boceprevir and GC376. Other ligands (P5, natural product from cardiospermum halicacabum and two synthetic molecules Q5 and PJ4) have shown comparable docking scores ranging -7.65 kcal/mol to -7.18 kcal/mol. Interestingly, we found all four top ligands had Pi bond interaction with the main amino acid residues HIS41 and CYS145 (catalytic dyad), H-bonding interactions with GLU166, ARG188, and GLN189, and hydrophobic interactions with MET49 and MET165 in the binding site of Mpro. According to the ADME analysis, Q5 and P5 are within the acceptable range of drug likeliness, compared to FG and PJ4. The interaction stability of the lead molecules with viral protease was verified using replicated MD simulations. Thus, the present study opens up the opportunity of developing drug candidates targeting SARS-CoV-2 main protease (Mpro) to mitigate the disease.Communicated by Ramaswamy H. Sarma.

Asunto(s)

Productos Biológicos , COVID-19 , Humanos , Productos Biológicos/farmacología , SARS-CoV-2 , Proteasas 3C de Coronavirus , Inhibidores de Proteasas/farmacología , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular

RESUMEN

Andrographis paniculata (Burm. f.) Nees and Andrographis nallamalayana J.L.Ellis have traditionally been used to treat various ailments such as mouth ulcers, intermittent fever, inflammation, snake bite. This study compares the comparative in vitro cytotoxic activity, and phytochemical profiling of methanol extract of A. nallamalayana (ANM) and A. paniculata (APM). UPLC-ESI-QTOF-MS/MS analysis has been performed. The cytotoxic activity of crude methanol extracts were evaluated against three different cancer cell lines (HCT 116, HepG2, and A549 cell line). Both plants' extract exhibited significant cytotoxic activity against tested cell lines in a dose-dependent manner. IC50 of ANM and APM in HCT 116 cell was 11.71 ± 2.48 µg ml-1 and 45.32 ± 0.86 µg ml-1 and in HepG2 cell line was 15.65 ± 2.25 µg ml-1 and 60.32 ± 1.05 µg ml-1 respectively. Cytotoxicity of these two extracts was comparatively similar in A549 cells. ANM induced cytotoxicity involved programmed cell death, externalisation of phosphatidylserine, ROS generation, up-regulation and down-regulation of major apoptotic markers. HRMS analysis of ANM and APM resulted in the identification of 59 and 42 compounds, respectively. Further, using the MS/MS fragmentation approach, 20 compounds, of which 18 compounds were identified for the first time from ANM, which belongs to phenolic acids, flavonoids, and their glycosides. Three known compounds, echioidinin, skullcapflavone I and 5,2',6'-trihydroxy-7-methoxyflavone 2'-O-ß-d-glucopyranoside, were isolated from A. nallamalayana and their crystal structures were reported for the first time. Subsequently, seven major compounds were identified in A. nallamalayana by direct comparison (retention time and UV-spectra) with authentic commercial standards and isolated compounds using HPLC-UV analysis. The cytotoxicity of phytochemicals from both the plants using in silico tools also justify their in vitro cytotoxic activity. It is the first report on the comparative characterisation of phytochemicals present in the methanolic extract of both the species of Andrographis, along with the cytotoxic activity of A. nallamalayana.