Covid-19: Antiviral therapeutics from herbs

Biochemicals from herbs used in traditional medicine might have a role to play in helping fight Covid-19 variants, according to new research.

Scientists in the UK, India, South Africa and South Korea have published a study in the May edition of the Journal of Cellular Biochemistry which shows phytochemicals could be potentially used as antivirals in pill form.

Co-author Dr Pattanathu Rahman, a Senior Lecturer at the Centre for Natural Products Discovery at Liverpool John Moores University, said: “There is a need for various treatment options for Covid-19 to slow infection rates and ease symptoms, and medicinal plants might prove to be a way forward.”

Despite significant advancements in the administration of vaccines across the globe, concerns have grown over the capacity of new variants to escape natural and/or vaccine-induced immunity.

Garlic and celery

Rahman and colleagues targeted viral and host proteins that have been implicated in COVID-19 illness that could provide significant therapeutic relief. They screened 605 phytocompounds from 13 medicinal plants, against the receptor-binding domain (RBD) of the spike proteins of the SARS-CoV-2 wild-type and variants Alpha, Beta, Gamma, Delta and Omicron, using molecular docking and dynamics simulations.

Plants with known antiviral and anti-inflammatory properties were selected, including garlic (Allium sativum), green chiretta (Andrographis paniculate), celery (Apium graveolens), Clerodendrum trichotomum, Cuminum cyminum, Curcuma longa, Justicia adhatoda, Melaleucan alternifolia, Ocimum sanctum, Petroselinum crispum, Punica granatum, Swertia chirata, and Vitex agnuscastus.

They found five phytocompounds could bind to the spike protein of SARS-CoV-2 and prevent the virus from entering cells and causing infection, potentially offering new avenues to prevent and treat the disease.

These were: abietatriene against the spike proteins of the SARS-CoV-2 wild type and variants; taraxerol against the human ACE2, CTSL and TNF-α; beta-amyrin against the human TMPRSS2; cynaroside against the human AAK1 and IL-1β; and friedelin against the human IL[1][1]6 and IFN-γ.  

Virus blockers

Explained Dr Rahman: “When they bind to the spike proteins those proteins can’t bind to the ACE2 enzyme, effectively acting as cell entry inhibitors.

“It is evidence that the herbs could be used to prevent SARS-CoV-2 infection and also to shorten infections by preventing virus particles from infecting human cells.

The present findings generate scope for future in vitro and in vivo studies with the proposed phytocompounds to validate their therapeutic potential against COVID-19.

Dr Rahman plans further testing with the collaboration of Liverpool School of Tropical Medicine.

The study – ‘Computational profiling of natural compounds as promising inhibitors against the spike proteins of SARS-CoV-2 wild-type and the variants of concern, viral cell-entry process, and cytokine storm in COVID-19’ is authored by Pallab Kar, Md. Moshfekus Saleh-E-In, Nishika Jaishee, Akash Anandraj,Emil Kormuth, Balachandar Vellingiri, Claudio Angione, Pattanathu K. S. M. Rahman, Suntheren Pillay, Arnab Sen, Devashan Naidoo, Ayan Roy and Young E Choi.