Isolation of bio-molecule Baicalein (5, 6, 7-Trihydroxy flavone) from root of Oroxylum indicum L. Vent and its prospective interaction with COVID-19 Viral S-Protein Receptor Binding Domain

Newly emerged COVID-19 performs its activity through spike protein receptor binding domain (RBD). A strong competitive binding on this site can inhibit the COVID-19 (SARS-CoV-2) activity against host cells. A significant plant bioactive molecule, Baicalein (5,6,7-Trihydroxyflavone), has noteworthy effects on viral S protein. The biomolecule was isolated from an endangered medicinal tree Oroxylum indicum L. Vent. Therapeutic use various parts of Oroxylum have been mentioned in ancient literature, Ayurveda and is also being used a folklore medicine in many tribal areas of India. Molecular docking has been applied to screen the binding pattern and bond strength of biomolecule with ten amino acids. The binding site was defined with site findder algorithm. The residues were found Arg403, Glu406, Lys417, Tyr453, Ser494, Tyr495, Gly496, Phe497, Asn501, Tyr505. The biomolecule Baicalein showed effective binding capacity towards active site residues of SARS-CoV-2 spike receptor-binding domain. It was found to have a strong binding affinity with RBD of S-protein of viral residues with high negative binding free energy (-12.5545 kcal/mol). Such competitive interruption of hydrogen bond formation between the viral S- protein and biomolecules’ active sites would inhibit the potency of COVID-19 infectivity.