The current COVID-19 pandemic that is spreading across countries originated in Wuhan, China.
The single cause of this highly communicable disease is a novel coronavirus, called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the seventh known virus of the Coronaviridae family capable of infecting humans.
The latest report from the World Health Organisation cited that there are now over 116 million confirmed cases and over 2.57million deaths worldwide caused by this virus.
The United States of America now has the highest number of COVID-19 cases (over 28.9 million cases), 120,000 deaths; followed by India (almost 11.2 million cases) and over 158,000 deaths and Brazil (over 10.8 million cases) and 261,000 deaths.
The fast propagation of this disease is mainly through close contact with infected individuals via respiratory droplets from either sneezing or coughing.
Furthermore, there are two other ways of transmitting the virus, including contact and aerosol transmission .
Coronavirus disease 2019 (COVID-19) is a new infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that belongs to the coronavirus family.
The first case was reported in December 2019, and the disease has become a pandemic.
Impaired immune regulation is one of the factors that play a role in its pathogenesis and results in poor outcomes of COVID-19 patients.
There have been many studies with drug candidates used as antivirals or immunomodulators.
However, the results of these investigations showed that the drug candidates were not significantly effective against the disease.
Meanwhile, people believe that consuming herbal immunomodulators can prevent or even cure COVID-19.
Unfortunately, specific pre-clinical and clinical trials to evaluate the effects of herbal immunoregulators have not been conducted.
Certain natural compounds might be effective for the treatment of COVID-19 based on general concepts from previous experiments.
Among infected patients, COVID-19 shows various unspecific symptoms, ranging from mild to severe.
A report from Huang et al. mentioned that fever (98 per cent) is the most frequent manifestation that is reported by patients, followed by cough (76 per cent), myalgia or fatigue (44 per cent), sputum production (28 per cent, and headache (eight per cent).
Also, some fatal cases have been reported in certain patients experiencing progressive respiratory failure due to the virus activity that attacks the alveolar epithelial cells.
This damage is initiated by the receptor- binding domain (RBD) attachment of the virus to the receptor on the respiratory tract, known as the angiotensin-converting enzyme-2 (ACE2) receptor.
Humans have many ACE2 receptors in their respiratory tracts, which increase their susceptibility to COVID-19.
This molecular mechanism may partly explain why the incidence rate of this disease is increasing rapidly.
Currently, there is no specific treatment for COVID-19.
Furthermore, people in the community and researchers are trying to find the best way to cure or prevent the disease, including using herbal medicine.
Since the immune status of patients plays an essential role in COVID-19 infection, herbal medicine, which has an immunomodulatory effect, could have potential as a preventive measure and even therapeutic agent for patients with COVID-19 infection.
A recent trend in the community is the consumption of herbal medicines containing certain active compounds, which have antimicrobial or antiviral, anti- inflammatory, and immunostimulatory activities such as echinacea.
These herbal compounds are assumed to have the capacity to modulate the immune response and, therefore, they are believed to have beneficial effects on preventing or treating COVID-19.
This article explains in detail the molecular pathomechanism of COVID-19 and how active compounds of herbal products might prevent or cure the disease.
It also will discuss the safety aspects of these natural compounds and provide recommendations for both the community and clinicians.
Characteristic of SARS-CoV-2
SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2, is one of the viruses that belong to coronaviruses.
This virus is reported to be one of the most wisest, fastest, deadlier and the most adaptable virus that has entered our world today.
The common coronavirus is a positive single-strand RNA virus (+ssRNA) that belongs to the order Nidovirales, family Coronaviridae, and sub family Orthocoronavirinae.
This specific coronavirus is divided into four genera: ALPHA, BETA, GAMA, and DELTA δ. Each genus is further divided based on the characteristics of its subtype, genome, and phylogenic clustering. At present, six types of coronavirus infect humans.
Coronavirus is a type of virus that has an envelope which is round or oval and is often pleomorphic.
The diameter of this virus is about 50–200 nm.
SARS-CoV-2 has a unique, club-shaped spike projection on the surface of the virus which makes this virus look like a solar corona.
There are four major structural proteins encoded by this novel coronavirus. They are the spike (S), membrane (M), envelope (E), and nucleocapsid (N) proteins.
The S protein is the most important structure that can bind with the receptor.
This glycoprotein is located on the surface of the virus and mediates the attachment to the host cell’s receptor.
This protein is also the main antigenic structure in this virus.
The S protein of this virus is a trimeric S glycoprotein, which is a class I fusion protein and mediates the attachment to the host cell’s receptor.
In most coronaviruses, the S protein is cleaved to a host cell furin-like protease into two polypeptides, which are known as S1 and S2. The S1 is part of a large RBD of the S protein, and the S2 forms the stalk of the spike protein structure.
The S protein of SARS-CoV-2 can interact strongly with the host cell via the ACE2 receptor.
This interaction creates a significant public health risk for human transmission.
After the S protein of the virus binds with ACE2, the virus envelope can fuse with the host cell membrane and enter the host cell.
The writer is a pharmacognost and Chief Medical Officer, CEO of the Medi Moses Group of Companies