The current pandemic of COVID-19 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 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.
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, an 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, quinine, and curcumin. 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.
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A PROMISING DEVELOPMENT IN THE FIGHT AGAINST COVID
Recent trials show how a domestically developed herbal remedy may unlock the mysteries of beating the coronavirus disease
Traditional Chinese medicine and other forms of herbal medicine have been suggested as treatments for COVID-19 patients.
Researchers in China and the United States have called for more research into the potential prophylactic effects of natural products and herbal medicines on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent coronavirus disease 2019 (COVID-19).
The potential effects of natural products and herbal medicines
Now, Chen and the team have published a review summarizing some recent findings regarding the potential effectiveness of natural products and herbal medicines in the inhibition of SARS-CoV-2 infection.
For example, they discuss compounds derived from natural products that may be effective against the cellular receptor heat shock protein A5 (HSPA5).
Some studies have reported that HSPA5 is recognized by the SARS-CoV-2 spike protein and one 2020 study showed that the phytoestrogens daidzein, genistein, formononetin, and biochanin A have binding affinities with HSPA5.
The researchers say these medicinal, plant-derived compounds may disrupt the attachment of SARS-CoV-2 to host cells (through spike), although their antiviral bioactivity requires further investigation.
The host cell enzyme transmembrane protease serine 2 (TMPRSS2) facilitates the entry of SARS-CoV-2 into host cells. Inhibition of this enzyme blocks the spike protein’s ability to fuse with the host cell receptor angiotensin-converting enzyme 2 (ACE2).
Using molecular docking and molecular dynamics simulations, one study conducted earlier this year demonstrated that withanone, a compound that can be isolated from Ashwagandha leaves (Withania somnifera) could bind to the catalytic site of TMPRSS2.
That study also confirmed that withanone significantly downregulated TMPRSS2 in the breast cancer cell line MCF-7, thereby pointing to its potential to dampen this enzyme’s function.
Many studies are preliminary, but some compounds have entered clinical trials
The researchers say that many of these studies are all still in the preliminary stages and further pre-clinical studies are needed to examine the antiviral effects of the compounds.
“It is undeniable that herbal medicine is still a promising resource for drug discovery, and its acceptable toxicity makes it a prospective prophylactic candidate against COVID-19,” write Chen and colleagues. In the face of this global health crisis, the team says that exploring prophylactics derived from herbal medicine likely represents a promising and practical approach to containing the pandemic.
Natural products and herbal medicine have a long track record in treating respiratory infections and many have been approved as drugs or over-the-counter food additives, say the researchers.
NATURAL PRODUCTS INHIBITING HUMAN CORONAVIRUS
Although combinatorial synthesis coupled with molecular docking help discover numerous synthetic drugs, more than one third of Food and Drug Administration (FDA)-approved drugs are natural products (Patridge et al., 2016). Plant, fungus and marine derived natural products have been rich resource of drug/nutrition discovery for many disease prevention (Tao et al., 2016; Wang et al., 2018; Lan et al., 2020). Natural products possess promising antiviral effects against human CoVs, which may guide the development of novel antiviral prophylactics.
Natural products and herbal medicine have long track record to treat respiratory infection and many have been approved as drugs, over-the-counter nutrition or food additives. Those products generally have satisfactory safety profiles. The minimal toxicity makes natural product and herbal medicines ideal prophylactic candidates for long-term use. Based on recent in silico results, an array of natural products has been found highly potent in blocking enzyme function and membrane receptors of human coronavirus. Moderate dosing of such bioactive compounds may prevent or at least slow down SARS-CoV-2 infection process. In addition, the progression of COVID-19 is featured with uncontrolled inflammation, like cytokine release syndrome, so anti-inflammatory herbs will be a potential tool to suppress such fatal symptom. The stability of natural products and herbal medicines in human gastrointestinal tract is barely an issue. The low pH in gastric environment, digestive enzymes, and gut microbiome have less impact on the bioavailability of natural products and herbs compared to antibody and other prophylactics. This advantage makes oral dosing rather than IV administration possible. In terms of availability, the ease of production expansion realizes the mass deployment of herbal medicines to big population, while the large-scale synthesis of monoclonal antibody and remdesivir is incredibly challenging. In this day and age, a safe, effective and stable form of oral dosage prophylactics will be a strong asset for us to overcome COVID-19 pandemic.
Front. Pharmacol., 16 October 2020 https://doi.org/10.3389/fphar.2020.588508 Current Prevention of COVID-19: Natural Products and Herbal Medicine
THAILAND
In June, Fah Talai Jone herb was formally approved for use in Thailand in treatment of mild COVID-19 symptoms
The National Drug Development Committee, headed by Public Health Minister Anutin Charnvirakul, has issued an announcement to add Fah Talai Jone to the national essential herbal medicine list, paving the way for its use in COVID-19 patients who are suffering mild symptoms. The announcement has been published in the Royal Gazette and is now in effect.
Few days ago, Prime Minister Prayut Chan-o-cha has instructed authorities to set up a committee to study the use of green chiretta (Andrographis paniculata) extracts to treat Covid-19 patients with mild symptoms. The decision was taken in response to a proposal from Justice Minister Somsak Thepsutin, who urged the government to scale up the use of traditional medicines on Covid-19 patients with mild symptoms.
His proposal came with evidence showing the Department of Corrections’ success in treating 12,376 inmates who were infected with Covid-19 with green chiretta extracts. Of this number, 5,045 inmates were in Chiang Mai Central Prison, 2,100 in Nonthaburi Provincial Prison and 5,231 in Bang Kwang Central Prison also in Nonthaburi.
NEW PROSPECTIVES
A traditional Chinese medicine formula NRICM101 to target COVID-19 through multiple pathways
NRICM101 (清冠一號), an herbal compound developed by the National Research Institute of Chinese Medicine (NRICM) in 2020, is believed to reduce the chance of severe illness as a result of COVID-19. It has been proven effective at inhibiting coronavirus replication and preventing the cytokine storm, in which the body attacks its own cells.
The medicine will become available in Thailand soon as Herbal Product
