Phytochemical rich Himalayan Rhododendron arboreum petals inhibit SARS-CoV-2 infection in vitro .

Phytochemicals with potential to competitively bind to the host receptors or inhibit SARS-CoV-2 replication, may prove to be useful as adjunct therapeutics for COVID-19. We profiled and investigated the phytochemicals of petals sourced from Himalayan flora, undertook studies and found it as a promising candidate against SARS-CoV-2. The phytochemicals were reported in various scientific investigations to act against a range of virus and which prompted us to test against SARS-CoV-2. assays of petals hot aqueous extract confirmed dose dependent reduction in SARS-CoV-2 viral load in infected Vero E6 cells (80% inhibition at 1 mg/ml; IC50 = 173 µg/ml) and phytochemicals profiled were subjected to molecular docking studies against SARS CoV-2 target proteins. The molecules 5-O-Feruloyl-quinic acid, 3-Caffeoyl-quinic acid, 5-O-Coumaroyl-D-quinic acid, Epicatechin and Catechin showed promising binding affinity with SARS-CoV-2 Main protease (M; PDB ID: 6LU7; responsible for viral replication) and Human Angiotensin Converting Enzyme-2 (ACE2; PDB ID: 1R4L; mediate viral entry in the host). Molecular dynamics (MD) simulation of 5-O-Feruloyl-quinic acid, an abundant molecule in the extract complexed with the target proteins showed stable interactions. Taken together, the phytochemical profiling, analysis and anti-viral assay revealed that the petals extract act upon M and may be inhibiting SARS-CoV-2 replication. This is the first report highlighting petals as a reservoir of antiviral phytochemicals with potential anti-SARS-CoV-2 activity using an system.