We got to the herbs: drugs against COVID-19 are extracted from plants

Little helpers

Researchers of the 27th Scientific Center of the Russian Defense Ministry have developed a biologically active supplement "KovBAD" capable of halving the viral load in the nasopharynx of a sick person already on the second day of use, and on the sixth - by 16 times. Lieutenant General Igor Kirillov, head of the radiation, chemical and biological protection troops, said this in an interview to the Krasnaya Zvezda newspaper.

"KovBAD" includes an extract of chokeberry, echinacea, fucoidan (polysaccharide contained in brown algae and some echinoderms), Pacific squid hydrolysate and other substances of natural origin that enhance antiviral protection. The drug has already received a certificate of state registration.

Dietary supplements usually contain natural immunomodulators, which weaken the effect of the virus on the body. As a result, the disease becomes easier.

But there are also natural substances that directly kill viruses, including SARS-CoV-2. These do not require additional safety tests because they are well known. But they are no substitute for pharmaceutical drugs.

"Dietary supplements in the early stages of infection help with the virus. At the same time, in principle, there cannot be any special ones - specifically against the coronavirus," explains Ancha Baranova, professor at the School of Systems Biology at George Mason University in the United States. - In general, there are many plants that contain substances that kill the coronavirus. You can take them, mix them in different combinations and register them as dietary supplements. It all depends on the proportions.

Natural substances against COVID-19

The effectiveness of many biologically active substances against coronavirus has been confirmed by clinical trials.

Most studies have focused on quercetin, a natural compound in the flavonoid group. It is found in onions, red grapes, honey, citrus fruits and other fruits and vegetables. Green tea and blueberries are particularly rich in it. This compound has antioxidant, anti-inflammatory and immunomodulatory properties, prevents free radicals from destroying cell membranes and can increase the intracellular concentration of zinc, a microcomponent that inhibits RNA virus replication.

Quercetin was tested in Saudi Arabia and recommended for prevention and treatment of mild early symptoms of COVID-19. The Saudis' example was followed in Italy, Turkey, Pakistan and Tunisia.

The flavonoid molecules target key viral proteins and the ACE2 membrane receptor, which the coronavirus uses to enter cells. Studies have shown that the flavonoids astragalin and kaempferol bind the two major virus enzymes 3CLpro and PLpro even more strongly than the antiviral drug remdesivir. Fizetine, isoramnetin and kaempferol block the virus' S-protein, while quercetin and kaempferol also inhibit the RdRp polymerase, which is necessary for viral RNA replication.

Artemisinin, a bioactive compound found in Artemisia annua, is also hoped for. It is already being used to treat malaria and some viral infections. Its safety for humans has been proven.

Plant-Based Drugs

Means against COVID-19 are also being sought among long-registered drugs of plant origin.

In February 2021, British scientists from the University of Nottingham together with their colleagues from the Chinese Agricultural University found that thapsigargin from the extract of the umbrella plant Thapsia gargantea is effective against SARS-CoV-2.

This drug was used against three major types of human respiratory infections: the "common cold" coronavirus group, respiratory syncytial virus (RSV) and influenza A. Laboratory studies on cell cultures and animals have demonstrated that thapsigargin is useful in prevention and treatment. It prevents SARS-CoV-2 replication in cells for at least two days, even after a single dose.

The new work concluded that thapsigargin is just as effective against alpha-, beta- and delta-variants of SARS-CoV-2. In addition, the authors claim, it can be used as a complex drug simultaneously against several infections, such as influenza, COVID-19 and RSV. And very small doses are sometimes enough to completely destroy the virus.

Biologists at the University of Michigan, after screening 1,400 FDA-approved drugs and supplements on cell cultures, identified 17 potentially effective compounds, among them the well-known dietary supplement lactoferrin, a protein derived from cow's milk.

"Lactoferrin suppresses the spread of SARS-CoV-2 in all cellular models in several ways. It prevents the virus from attaching to heparan sulfate (whose molecules are inside the cell) and enhances interferon production," the study authors point out.

The drug as a cure for COVID-19 is undergoing clinical trials in Egypt and Italy.

Vegetables, fruits, and other foods

German scientists recently found that pomegranate juice, blackthorn rowanberry juice and green tea help with influenza and SARS-CoV-2. Plant polyphenols, including flavonoids, found in these drinks suppress the coronavirus, but only at the initial stage, when the infection is still in the nasopharynx. They recommend rinsing your mouth and throat with these juices and teas for prevention.

Italian scientists have demonstrated that the biologically active substances contained in pomegranate peel extract, especially the polyphenols punicalagin and theaflavin, weaken the interaction between the S-protein of coronavirus and cell receptor ACE2, and also suppress the activity of the main protease SARS-CoV-2 - 3CLpro, which is necessary for the virus to replicate and survive in the body. This was confirmed by biologists from Bosnia and Herzegovina and Serbia.

Curcumin from turmeric root and catechins, which are present in large quantities in green and white tea, dark chocolate and many fruits and berries, prevent the virus from multiplying. Campferol (found in rose hips, cumin, dill, licorice, beans, and tea), naringenin (a polyphenol rich in citrus fruits and tomatoes), dihydroquercetin (a bioflavonoid from Siberian larch extract).

The U.S. National Institutes of Health (NIH) mentions andrographis, echinacea, elderberry, and ginseng as potentially effective plants against coronavirus in their official bulletin on dietary supplements.

Andrographis paniculata is an herb that grows in the subtropics of Southeast Asia. It is used in traditional Ayurvedic, Chinese and Thai medicine for colds, flu and other respiratory tract infections. There are studies confirming potential efficacy against SARS-CoV-2. Clinical trials have been in Thailand and Georgia.

Echinacea is a perennial flowering plant similar to chamomile, only with colored petals. It is found in North America and Europe. Its extract is often found in supplements, although the active ingredients have not been fully identified. It has antioxidant and antibacterial properties, stimulates natural killer cells, prevents the virus from binding to host cells, and attenuates inflammation by inhibiting inflammatory cytokines. According to a preliminary analysis, the echinacea-based drug inactivates SARS-CoV-2. Clinical trials have been organized in Spain, Iran and Bulgaria.

"Elderberry may act as an antioxidant, reduce inflammation and fight viruses," the NIH bulletin says. Elderberries contain many bioactive substances, including anthocyanins, flavonols and phenolic acids.

Preclinical animal trials have shown that these plants help prevent upper respiratory tract infections by preventing viruses from binding to cells and stimulating the immune system. However, how all this will work on COVID-19 patients is unknown.

Traditional Medicine

Ginseng is one of the few plants of traditional Oriental medicine that is well known in the Western world. Southeast Asia, especially China, has relied on phytotherapy since the beginning of the pandemic. The National Health Commission of China has authorized the use of herbal-based folk remedies in combination with Western medicine for patients with COVID-19 and has issued several herbal treatment recommendations.

An article prepared by scientists from China, Bangladesh, Malaysia and the United States confirms the effectiveness of traditional Chinese and Ayurvedic medicines against the coronavirus. Some of them, such as "Kan-Yang," are also known in Russia.

But all of these are only small helpers.

"Now dietary supplements are being registered in many countries. In the PRC these are the famous Chinese herbal mixtures, which are thousands of years old. They have been tested against the coronavirus, and they also work, that is, they are a plus. But no one is saying that they save from COVID-19," emphasizes Professor Baranova.

"There are no studies proving that any dietary supplements can prevent COVID-19 or markedly alleviate the disease," the NIH website acknowledges.

Their colleagues from Rospotrebnadzor agree with the American specialists: "Unfortunately, biologically active supplements will not protect from coronavirus.

Rospotrebnadzor experts do not advise to trust the advertising of dietary supplements that help against the infection. It misleads the consumer.

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