COVID-19 Herbs: Scientist Say That Herbs And Phytochemicals Have Potential To Fight The COVID-19 Pandemic
: Scientist from Jinan University-China, University of Houston-United States, University of California-United States and Beijing University of Chinese Medicine-China are calling for more research into the potential prophylactic effects of herbs, phytochemicals and traditional medicines on SARS-CoV-2 infection and the subsequent COVID-19 disease.
The scientists said that although so far, several vaccine candidates have advanced into clinical trials, limited data have been released regarding the vaccine efficacy and safety in human, not mention the long-term effectiveness of those vaccines remain as open question yet. Herbs, phytochemicals and natural medicines have been historically used for acute respiratory infection and generally show acceptable toxicity. The favorable stability for oral formulation and ease of scaling up manufacture make it ideal candidate for COVID-19 prophylactics.
The study team summarized the most recent advance in SARS-CoV-2 prevention including vaccine development as well as experimental prophylactics. Mainly, they reviewed the herbs and natural products showing inhibitory effect on human coronavirus, and discussed the herbal medicines lately used for COVID-19, especially focused on the herbal products already approved by regulatory agency with identifiable patent number.
They demonstrated that to fill in the response gap between appropriate treatment and commercially available vaccine, repurposing natural products and herbal medicines as prophylactics will be a vigorous approach to stop or at least slow down SARS-CoV-2 transmission. In the interest of public health, this will lend health officials better control on the current pandemic.
The study cum review was published in the journal: Frontiers in Pharmacology. https://www.frontiersin.org/articles/10.3389/fphar.2020.588508/full
The study team discussed natural products that have exhibited an inhibitory effect on SARS-CoV-2 and herbal medicines that have been tested as potential therapies for COVID-19.
Corresponding author Dr Jia-xu Chen from Jinan University in Guangzhou told Thailand Medical news, "In this review, we aimed to provide a new perspective regarding COVID-19 prevention.”
The study team suggests that while the world awaits effective treatments and a commercially available vaccine, the repurposing of natural products and herbal medicines as prophylactics represents a promising approach to at least slow the transmission of SARS-CoV-2.
The COVID-19 disease is caused by the betacoronavirus SARS-CoV-2, which initiates infection using a surface structure called the spike protein that binds to and fuses with target host cells.
Though several vaccine candidates are under evaluation in clinical trials, not one has yet been approved for use, and their long-term effectiveness is uncertain.
Besides vaccine development, intense efforts have also been focused on finding effective prophylactics against COVID-19 among high-risk populations.
Dr Chen said, "Since the outcome of current therapeutics in severe/critical COVID-19 patients are still debatable,
prevention rather than treatment becomes more important to restrain this pandemic."
He added, "Blocking the entry of SARS-CoV-2 and suppressing infection at the initial stage is considered a more practical strategy."
The team said that historically, natural products and herbal medicines have been used for the prevention of viral infections and generally show favorable efficacy and acceptable toxicity.
Dr Chen and the rest of the study 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 instance, they discuss compounds derived from natural products that may be effective against the cellular receptor heat shock protein A5 (HSPA5).
Certain 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 study team says that 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.
It was found that 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).
Utilizing 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. https://www.tandfonline.com/doi/full/10.1080/07391102.2020.1775704
Interestingly 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.
SARS-CoV-2 papain-like protease (PL pro) cleaves the viral polyproteins which is essential for its survival and replication. Thus, PL pro is one of the prospective drug targets of SARS-CoV-2. A previous study established a library of small molecules found in rhizomes, Alpinia officinarum (Alpinia officinarum Hance), ginger (Zingiber officinale Roscoe), and curcuma (Curcuma longa L.). The compounds were docked into the solvent accessible S3-S4 pocket of PLpro. In silico results showed eight lead compounds from galangal (Alpinia officinarum Hance) and ginger (Zingiber officinale Roscoe) bound with high affinity to SARS-CoV-2 PLpro, suggesting their potential as inhibitors against SARS-CoV-2. However, subsequent in vitro and in vivo experiments are needed to elucidate their efficacy against SARS-CoV-2. https://chemrxiv.org/articles/Natural_Product_Compounds_in_Alpinia_officinarum_and_Ginger_are_Potent_SARS-CoV-2_Papain-like_Protease_Inhibitors/12071997
Besides S protein and PLpro, the other promising drug target for combating the infection of SARS-CoV-2 is 3-chymotrypsin-like protease (3CLpro, also known as main protease). The conserved 3CLpro controls virus replication. Another study had screened a series of alkaloids and terpenoids derived from African plants as potential inhibitors of 3CLpro using molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) virtual analysis by the SuperPred webserver. The results revealed that 10-Hydroxyusambarensine, Cryptoquindoline, 6-Oxoisoiguesterin, and 22-Hydroxyhopan-3-one might be potent inhibitors with greatest drug-likeness against SARS-CoV-2 3CLpro. https://www.tandfonline.com/doi/full/10.1080/07391102.2020.1764868
RNA-dependent RNA polymerase (RdRp) is an essential virus replicase that catalyzes the synthesis of complementary RNA strands using the virus RNA template. The molecular structure of RdRp was revealed in May 2020, providing a new strategy for discovering prophylactic candidates for SARS-CoV-2 inhibition. https://science.sciencemag.org/content/368/6492/779.abstract
Yet another study investigated the potential of eight natural polyphenols (quercetin, naringenin, caffeine, oleuropein, ellagic acid, benzoic acid, resveratrol, and gallic acid polyphenols) as inhibitors of SARS-CoV-2 RdRp by molecular docking assay. https://www.researchsquare.com/article/rs-25850/v1
The studied polyphenols formed hydrogen bonds with the nucleotide triphosphate (NTP) entry channel amino acids (ARG 555, ARG 555, LYS 545) in SARS-CoV-2 RdRp (except caffeine and oleuropein). Binding to NTP may inhibit the entry of the substrate and subsequently repress the enzyme activity. The results suggested that gallic acid and quercetin exhibited high binding affinity to RdRp. The NSP12 is an important RdRp for the coronavirus replicative machinery, which binds to co-factors NSP7 and NSP8 to activate its ability to replicate long RNA.
A recent study has established two homologous models for virtual screening. Cepharanthine, an alkaloid tetrandrine isolated from Stephania (Stephania tetrandra S.Moore), has been reported to have anti-inflammatory and antioxidant activities. The study has shown Cepharanthine could bind to the interface active pockets of the SARS-CoV-2 NSP12-NSP8, suggesting it has therapeutic potential. https://pubmed.ncbi.nlm.nih.gov/31502247/
Although many studies are preliminary, but some compounds have entered clinical trials though most are merely observational clinical trials.
The study team 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.
Dr Chen said, "In the meanwhile, a great number of clinical trials have registered to investigate the potentials of natural product to halt disease progression.”
Significantly one such trial is investigating the immunomodulatory and antiviral activity of Nigella sativa seed oil among adult patients hospitalized with COVID-19 showed remarkable effects. https://clinicaltrials.gov/ct2/show/NCT04401202
Also another trial is currently recruiting participants to study the effectiveness of vitamin C at reducing mortality among patients. https://pubmed.ncbi.nlm.nih.gov/32404477/
Dr Chen further added, "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.”
The study team says that In the face of this global health crisis, exploring prophylactics derived from herbal medicine likely represents a promising and practical approach to containing the pandemic.
Most 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.
The team concludes, "Moderate dosing of such bioactive compounds may prevent or at least slow down the SARS-CoV-2 infection process.”
Sadly in a country like Thailand, herbal and phytochemical research does not get any support from any government agencies and also from the greedy and corrupted Thai corporations or the rich.
The country is simply full of ignorant, selfish and greedy individuals who do not understand the importance of herbal medicine or even proper research and most are interested in profits and are not really into developing real efficient products that have proper scientific studies done and that can reach the masses either cheaply or for free.
We at Thailand Medical news, despite taking so much time and resources in developing a line of therapeutic herbal teas and herbal products as prophylactics and also as an adjuvant to treat COVID-19 with proper research and a scientific approach with most a bulk of the monies coming out from our own pockets, have never got any real proper support from any Thai entities. https://www.thailandmedical.news/news/new-therapeutic-teas-
Despite making so many appeals, we only had one Thai forest monk and one generous and kind Thai who supported our appeals. Despite still lacking about US$96,000 to continue our research, development and production, our appeals for help and donations have not got any Thai reactions or even from our readers. In this doomed country , even criminals accused of child murder can get donations of millions of baht but for a small entity trying to secure funding for herbal research and for developed products to be distributed free to the masses, we get no support.
We have decided to halt operations of this website with effect from the 1st
of December as it is proving to be a financial burden and really does not benefit us. Its cursed to be operating from third world country with masses that are stupid and only engrossed in stupid things and garbage like Korean boy bands, porn, cartoons , celebrities, gossip news and politics.
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