Herbs For COVID-19: Study Shows That Phytochemicals From Cat’s Claw (Uncaria Tomentosa) Effectively Inhibits SARS-CoV-2 In Vitro Research

Herbs For COVID-19: A Colombian and Peruvian study involving scientist from the University of Antioquia-UdeA-Colombia, Universidad de Antioquia UdeA-Colombia, Universidad Cooperativa de Colombia and Universidad Nacional Mayor de San Marcos-Peru have demonstrated in proper and credible in vitro studies that phytochemicals present in Cat’s Claw (Uncaria Tomentosa) is able to inhibit replication activity of the SARS-CoV-2 coronavirus. (Strains used for the study were taken from the hCoV-19/Colombia/ANT-UdeA-200325-01/2020)


 
The study team investigated the antiviral potential of the hydroalcoholic extract of Uncaria tomentosa stem bark from Peru against SARS-CoV-2 in vitro. The antiviral activity of U. tomentosa against SARS-CoV-2 in vitro was assessed in Vero E6 cells using cytopathic effect (CPE) and plaque reduction assay. After 48hours of treatment, U. tomentosa showed an inhibition of 92.7 % of SARS CoV-2 at 25.0 µg/mL (p <0.0001) by plaque reduction assay on Vero E6 cells. In addition, U. tomentosa, induced a reduction of 98.6 % (p=0.02) and 92.7 % (p=0.03) in the CPE caused by SARS-CoV-2 on Vero E6 cells at 25 µg/mL and 12.5 µg/mL, respectively. The EC50 calculated for U. tomentosa extract by plaque reduction assay was 6.6 µg/mL (4.89 – 8.85 µg/mL) for a selectivity index of 4.1. The EC50 calculated for U. tomentosa extract by TCID50 assay was 2.57 µg/mL (1.05 – 3.75 µg/mL) for a selectivity index of 10.54.
 
These study results showed that U. tomentosa known as Cat´s claw has antiviral effect against SARS-CoV-2 observed as a reduction in the viral titer and CPE after 48hours of treatment on Vero E6 cells. The study team hypothesizes that U. tomentosa stem bark, could be promissory to the development of new therapeutic strategies against SARS-CoV-2.
 
The study findings were published on a preprint server and are currently being peer reviewed. https://www.biorxiv.org/content/10.1101/2020.11.09.372201v1
 
Thailand Medical News had already covered a computational molecular docking study showing the possible effectives of phytochemicals from Cat’s Claw to inhibit the protease MPro replication process in SARS-CoV-2 coronaviruses in July this year. https://www.thailandmedical.news/news/must-read-covid-19-supplements-scientists-exploring-inhibitory-properties-of-uncaria-tomentosa-cat-s-claw-against-sars-cov-2-main-protease-mpro
 
This new research propelled by Thailand Medical News research initiatives was conducted in what could be termed as proper and credible in vitro studies with proper cell lines and state of the cell lines being properly ascertained along with SARS-CoV-2 virus isolates and strains identified with proper laboratory settings.
 
Cat's claw (Uncaria tomentosa) is a woody vine found in the tropical jungles of South and Central America. It is known as cat's claw or uña de gato in Spanish because of its claw-shaped thorns. The plant root bark is used in herbalism for a variety of ailments, and i s also sold as a dietary supplement.
 
Cat’s claw contains more than 50 phytochemicals that have various therapeutic effects.
https://zone.biblio.laurentian.ca/bitstream/10219/2464/1/FINAL%20THESIS_Aljehani,%20Areej.pdf
 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6365538/
 
https://www.mdpi.com/2076-3417/10/8/2668/htm
 
https://www.sciencedirect.com/topics/medicine-and-dentistry/uncaria-tomentosa
 
Oxindole alkaloids (pentacyclic oxindole alkaloids (POA) and tetracyclic oxindole alkaloids (TOA)) have been recognized as fingerprint of this species in some pharmacopeias and several pharmacological activities are linked to this kind of alkaloids. https://pubmed.ncbi.nlm.nih.gov/15649507/
 
https://pubmed.ncbi.nlm.nih.gov/27169179/
 
It has been demonstrated that Uncaria tomentosa (U. tomentosa) exerts an antiviral effect on human monocytes infected with dengue virus 2 (DENV-2) and herpes simplex virus type 1 (HSV-1). https://pubmed.ncbi.nlm.nih.gov/18279801/
 
https://www.sciencedirect.com/science/article/abs/pii/S0278691514000271?via%3Dihub
 
In previous studies in silico, U. tomentosa´s components inhibited the SARS-CoV-2 enzyme 3CLpro and disrupted the interface of the receptor-binding 89 domain of angiotensin-converting enzyme 2 ( RBD–ACE-2) as well as the SARS-CoV-2 spike glycoprotein. https://www.preprints.org/manuscript/202006.0326/v1
 
https://www.tandfonline.com/doi/full/10.1080/07391102.2020.1837676
 
Additionally, bio-activities as anti-inflammatory, antiplatelet and immunomodulatory were demonstrated. Furthermore, other components isolated from the stem bark such as quinovic acids, polyphenols (flavonoids, proanthocyanidins, and tannins), triterpenes, glycosides and saponins were identified by instrumental methods.
 
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2036.1998.00424.x
 
https://www.sciencedirect.com/science/article/abs/pii/S0378874120333808?via%3Dihub
 
https://www.sciencedirect.com/science/article/abs/pii/S0963996913001476?via%3Dihub
 
In this study, the researchers found that the hydroalcoholic extract of Uncaria tomentosa inhibited SARS-CoV-2 viral replication and reduced its cytopathic effect on Vero E6 cells.
 
The study team said that this is the first study to test the effects of U. tomentosa on SARS-CoV-2.
 
Co-researcher Dr Wildeman Zapata reports that U. tomentosa reduced the viral titer and cytopathic effect of SARS-CoV-2 in the Vero E6 cell line after just 48 hours of treatment.
 
Dr Zapata told Thailand Medical News, "Based on our results, U. tomentosa is a promising medicinal herb to combat COVID-19, but it is necessary to continue with animal models followed by clinical trials to validate our results in the context of COVID-19 patients.”
 
To date there are no effective drugs to treat COVID-19 and even the WHO is now recognizing that traditional, complementary, and alternative medicine has many benefits. Several candidates with possible antiviral effects have been explored from medicinal plants in the preclinical phase. https://www.afro.who.int/news/who-supports-scientifically-proven-traditional-medicine
 
The research team says, "Herbal medicines could become a promising option to tackle the ongoing pandemic caused by COVID-19.”
 
The preclinical evaluation of natural compounds that might inhibit SARS-CoV-2 could lead to the discovery of new antiviral drugs and a better understanding of the viral life cycle, suggests the team.
 
The study team assessed the antiviral activity of the hydroalcoholic extract of U. tomentosa stem bark in Vero E6 cells using a plaque reduction assay and a test of cytopathic effect (CPE).
 
48 hours following treatment, the plaque reduction assay showed that U. tomentosa extract had inhibited the number of infectious SARS-CoV-2 particles by 92.7% at a dose of 25.0 µg/mL.
 
Significantly treatment with the extract also reduced the CPE by 98.6% at 25 µg/mL and 92.7% at 12.5 µg/mL.
 
The research shows that U. tomentosa exerts antiviral activity against SARS-CoV-2 in Vero E6 cells, as demonstrated by a reduction in viral titer and CPE just 48 hours following treatment, say the researchers.
 
The study team said, “Based on our results, U. tomentosa is a promising medicinal herb to combat COVID-19,” write Zapata and colleagues. “However, further specific in vitro assays combined with in vivo studies need to be carried out to validate this in-vitro finding.”
 
The study team says they hope the findings will support the continued investigation of U. tomentosa and ultimately lead to validation of its clinical use in medical trials.
 
Thailand Medical News has been propelling research using herbs as a possible treatments for COVID-19 since February and has been supporting researchers around the world in various molecular docking studies, in vitro studies and vivo studies using an array of herbs and phytochemicals while at the same pushing for proper in vitro study standards and for testing of all therapeutics against a broader range of SARS-CoV-2 isolates and strains.
 
To date Thailand Medical News had created a few patented tea blends that incorporate the nano-technology encapsulated phytochemicals along with a variety of tested herbs to be used as an adjuvant to treat COVID-19 and at the same time be used as prophylaxis against the COVID-19 disease. https://www.thailandmedical.news/news/new-therapeutic-teas-
 
We are also incorporating genetic and epigenetic based strategies in our therapeutic teas and not just antiviral, anti-inflammatory, anti-clotting and immunomodulatory properties.
 
We are at the same time creating products lines for long term COVID-19 health complications and also lines for infants and young children.
 
Unlike the usage of single herb based platform, we are using multiple herbs and phytochemicals so that our products are effective against a wide range of SARS-CoV-2 strains and are also able to deal with varying human gene issues and also to prevent resistance developing.
 
Thailand Medical News needs your help urgently as we are still trying to raise another US$96,000 for additional research. To date we have spent almost 43 million Thai baht of our own monies on this various herb research.
 
Despite so many appeals, we have only had one kind generous Thai donor who has helped us so far. We hope that more people will not simply ignore our plea for help and will be kind enough to help us in this noble cause. https://www.thailandmedical.news/p/sponsorship

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