Phyto-Compounds from a Rather Poisonous Plant, Strychnos nuxvomica, Show High Potency Against SARS-CoV-2 RNA-Dependent RNA Polymerase.

BACKGROUND: The establishment of strategy to inhibit the virus replication is an attractive means in combating SARS-CoV-2 infection. OBJECTIVE: We studied phyto-compounds from Strychnos nux-vomica (a poisonous plant) against SARS-CoV-2 RNA-dependent RNA polymerase by computational methods. METHODS: Molecular docking, molecular dynamics (MD) simulation and energetics calculations were employed to elucidate the role of the phyto-compounds. RESULTS: Ergotamine with a binding free energy of -14.39 kcal/mol showed a promising capability in terms of binding affinity and the interaction to conserved motifs, especially the SDD signature sequence. The calculated dissociation constants for ATP, ergotamine, isosungucine and sungucine were 12 µM, 0.072 nM, 0.011 nM and 0.152 nM, respectively. The exhibited kd by these phyto-compounds reflected tens of thousands fold potency as compared to ATP. The binding free energies of sungucine and isosungucine were much lower (-13.93 and -15.55 kcal/mol, respectively) compared to that of ATP (-6.98 kcal/mol). CONCLUSION: Sharing the same binding location as that of ATP and having high binding affinities, Ergotamine, Isosungucine, Sungucine and Strychnine N-oxide could be effective in controlling the SARS-CoV-2 virus replication by blocking the ATP and inhibiting the enzyme function.

International Conference on Pharmaceutical Material, Engineering and Applied Science (ICOPMES) 2020

This proceedings contains 13 papers focusing on the effect of green tea extract in modulating the antibacterial activity of standard antibiotics against clinical isolates of Acinetobacter baumannii, in silico screening of Ziziphus spina-christi and Strychnos ligustrine compounds as a proteinase inhibitor of SARS-COV-2, antioxidant and antifungal propterties of palu shallot (Allium ascalonicum var. aggregatum), probiotic properties and safety of lactic acid bactera isolated from South Sulawesi ethnic cheese, pharmacognostics of 2 Orthoshipon aristatus varieties and effect of honey consumption after physical exercises on electrolytes and blood sugar levels, among others.

In silico screening of Ziziphus spina-christi (L.) Desf. and Strychnos ligustrine compounds as a protease inhibitor of SARS-CoV-2

Diseases caused by the coronavirus have become an important concern in early 2020. The coronavirus is a new type of virus that is included in the SARS-CoV-2 group. One of the possible mechanisms of SARS-CoV-2 inhibition involves protease receptors inhibition. This research was aimed to in silico screening of Ziziphus spina-christi (L.) Desf., and Strychnos ligustrine active ingredients as the main protease inhibitors of SARS-CoV-2 by assessing the ligand-binding affinity in the binding pocket of SARS-CoV-2 main protease protein. The molecular docking method is generally used to predict the inhibitory site and bonds formation. In the current study, some generally used antiviral compounds from the PDB (Protein Data Bank) were also used to compare the affinity strength of the test compound against the protease receptor (code of 5R7Y). The inhibitory activity against the main protease receptor proven by the ChemPLP score is more negative than the receptor's native ligand and the comparison compounds. Jubanine B, a compound of Z. spina-christi has the most robust inhibition activity on the SARS-CoV-2 protease receptor. Results of this study can be concluded that this can be used to develop as a candidate for traditional medicine against SARS-CoV-2 but still it required some more in vitro and in vivo studies.

In silico screening of therapeutic potentials from Strychnos nux-vomica against the dimeric main protease (Mpro) structure of SARS-CoV-2.

The novel coronavirus also referred to as SARS-CoV-2 causes COVID-19 and became global epidemic since its initial outbreak in Wuhan, China, in December 2019. Research efforts are still been endeavoured towards discovering/designing of potential drugs and vaccines against this virus. In the present studies, we have contributed to the development of a drug based on natural products to combat the newly emerged and life-threatening disease. The main protease (MPro) of SARS-CoV-2 is a homodimer and a key component involved in viral replication, and is considered as a prime target for anti-SARS-CoV-2 drug development. Literature survey revealed that the phytochemicals present in Strychnos nux-vomica possess several therapeutic activities. Initially, in the light of drug likeness laws, the ligand library of phytoconstituents was subjected to drug likeness analysis. The resulting compounds were taken to binding site-specific consensus-based molecular docking studies and the results were compared with the positive control drug, lopinavir, which is a main protease inhibitor. The top compounds were tested for ADME-Tox properties and antiviral activity. Further molecular dynamics simulations and MM-PBSA-based binding affinity estimation were carried out for top two lead compounds' complexes along with the apo form of main protease and positive control drug lopinavir complex, and the results were comparatively analysed. The results revealed that the two analogues of same scaffold, namely demethoxyguiaflavine and strychnoflavine, have potential against Mpro and can be validated through clinical studies.Communicated by Ramaswamy H. Sarma.