As the coronavirus panic continues to spread, I figured now would be a good time to write an article about potential herbal treatment. I have summarized most of the herbs that may be effective against COVID-19 (otherwise known as SARS-CoV-2 or 2019-nCoV) based on molecular docking and previous experience from SARS and MERS outbreaks. Do keep in mind that each herb and its respective constituents work differently and while some of these are direct inhibitors of replication, others might be helpful in managing the symptoms. Many of the studies that provide information about these are based on older data. The last section of this article comprises my personal recommendations that I do believe may be helpful in managing the symptoms, most of them even having antiviral effects. Although COVID-19 is a new virus, it bears similarities to the previous SARS-CoV and MERS-CoV, thus herbs effective against these strains may also be effective against the latest coronavirus. The genome of SARS-CoV-2 has been shown to be 89% similar to the genome of the original virus. These similarities are mainly in the proteins that are responsible for the virus’ life cycle.

The main molecular targets that are the subject of research are PLpro protease, 3CLpro protease and spike protein. Several studies have shown that 2019-nCoV spike protein (S-protein) utilizes ACE-2 receptors to facilitate viral entry. Angiotensin-converting enzyme 2 (ACE-2) is a receptor that is commonly found in lungs and gastrointestinal tract, making it a perfect candidate for the viral entry. Additionally, the structure of the S-protein closely resembles the structure of the S-protein contained within SARS-CoV, thus confirming its importance in initial infection. The main protease (3CLpro) is also a very decent target for drug development as it’s very likely that it’s one of the main enzymes responsible for replication and life cycle of the virus.

So what are some symptoms of the infection?

Symptoms of infection range from breathing difficulties; lymphocytopenia (low white blood cell levels); elevated liver enzymes; elevated LDH (lactate dehydrogenase), CK-MB (creatine kinase myocardial band), ESR (erythrocyte sedimentation rate), CRP (C-reactive protein); diarrhea; fever; dry cough; fatigue; emesis; sore throat; ARDS (acute respiratory distress syndrome); shock; pneumonia; sputum; dyspnea; acidosis; hemorrhage; kidney failure. What makes this virus worse than MERS and SARS is that people can remain as asymptomatic carriers for longer periods of time thus ensuring its stealthy spread.

Curious about the current statistics about the number of infected in the world? Click here.

Herbs with little to no toxicity that may be beneficial

  1. Red sage (root) [Salvia miltiorrhiza] – contains tanshinones (specifically dihydrotanshinone I, tanshinone IIa, cryptotanshinone) which are all potential inhibitors of the molecular targets mentioned above
  2. Honeysuckle (flower) [Lonicera japonica] is an excellent non-toxic herb that not only serves to inhibit the replication/viral entry, but it also helps with the symptoms, especially with breathing difficulties and sore throat
  3. White mulberry (leaf + cortex) [Morus alba] – contains mulberroside A
  4. Chinese gold thread (root) [Coptis chinensis] – contains berberine and various other isoquinoline alkaloids that are very effective
  5. Cork tree (bark) [Phellodendron amurense/chinensis] – contains berberine and other alkaloids that may be useful in managing the infection
  6. Houttuynia (aerial parts) [Houttuynia cordata] – incredibly potent universal antiviral herb; do keep in mind that it may contain oxalates, so limit your use if you are experiencing kidney issues
  7. Anemarrhena (root) [Anemarrhena asphodeloides]
  8. Horny goat weed (leaf) [Sagittatum epimedium]
  9. Astragalus (root) [Astragalus membranaceus] with the active compound being astragaloside A
  10. Drynaria fortunei (root) – contains naringin and naringenin
  11. Isatis tinctoria (aerial parts) – should not be that bad for short-term use, do be careful with this herb if you are suffering from any kidney disease

Toxic herbs

  1. Licorice (root) [Glycyrrhiza glabra or other species] – contains glycyrrhizin which is almost always active against some kind of a virus. Use only in small doses because its toxicity targets several of the body’s systems.
  2. Chrysanthemum morifolium (flower) – potential pyrethrin poisoning, you can expect a lot of toxic side effects
  3. Hoveniae dulcis (seed) – hepatotoxic
  4. Coltsfoot (flower) [Tussilago farfara] – hepatotoxic
  5. Euphorbiae helioscopiae (aerial parts) – highly toxic, I do not recommend using this one
  6. Ginkgo biloba (seed) – since the aerial parts are carcinogenic, my guess would be that the seeds are even more toxic.
  7. Chinese skullcap (root) [Scutellaria baicalensis] – contains baicalein which has previously been used to treat SARS and seems to have a beneficial effect against COVID-19 as well. Use only in small doses as this herb is hepatotoxic.
  8. Bupleurum spp. (root) – hepatotoxic, contains active saikosaponins
  9. Ardisia japonica (aerial parts) – nephrotoxic

Grey area (herbs I have very little information about)

  1. Peucedanum praeruptorum (root)
  2. Forsythia suspensa (fruit) – another popular Chinese antiviral that you will find in many preparations, contains forsythiaside A
  3. Erigeron breviscapus
  4. Inula japonica (flower)
  5. Eriobotrya japonica (leaf)
  6. Hedysarum multijugum maxim.
  7. Aster tataricus (root)
  8. Veratrum nigrum root, contains stilbenes and alkaloids that may block binding of ACE2
  9. Platycodon grandiflorum (root)
  10. Atractylodes macrocephala (root) –not that toxic, but very irritating, contains Atractylenolide I
  11. Saposhnikovia divaricate (root)
  12. Glehnia littoralis (root)
  13. Phragmites communis (root)
  14. Alnus japonica

Compounds

  1. Betulinic acid, present in a variety of herbs, may inhibit replication and 3CLpro. I recommend using self-heal (Prunella vulgaris/asiatica) as the least toxic source.
  2. Sugiol – inhibits replication and 3CLpro
  3. Emodin – blocks spike protein. Emodin is a constituents of multiple herbs, most notably rhubarb root, Japanese knotweed and buckthorn. I recommend using the root of Japanese knotweed (Polygonum cuspidatum) as it’s the least toxic of emodin containing herbs.
  4. Quercetin & kaempferol – inhibit PLpro and 3CLpro, found in a majority of herbs in varying concentrations
  5. Rutin & Chlorogenic acid – also found in most of the herbs
  6. Coumaroyltyramine –inhibits PLpro and 3CLpro, found in onion species
  7. Moupinamide – inhibits PLpro
  8. Formononetin – phytoestrogen found in various foods and herbs, potentially active against SARS
  9. Herbacetin
  10. Rhoifolin
  11. Pectolinarin
  12. Naringin, naringenin, hesperetin, hesperidin – found in citrus fruits, just be sure that those have low coumarin contents as you do not want to overload your liver with hepatotoxic coumarins
  13. Puerarin – found in kudzu root
  14. Orientin
  15. Amygdalin – present in pits of fruits and bitter almonds, toxic
  16. Geniposide – found in hepatotoxic fruits of Gardenia jasminoides
  17. Magnolol – from bark of Magnolia officinalis
  18. Pulegone – present in toxic herbs
  19. Ilexgenin A – from Ilex species
  20. Paeoniflorin – present in Paeonia lactiflora and other species. Highly recommended, especially for women.
  21. Arctiin – mostly obtained from various burdocks
  22. 6-gingerol – as the name suggests, ginger root is the primary source of this compounds
  23. Harpagide
  24. Demethyl-coclaurine
  25. Eriodictyol – a good and non-toxic source of this compound may be rosehips

Personal recommendations

  1. Elderberry (flower + fruits) [Sambucus nigra]
  2. Holy basil (aerial parts) [Ocimum sanctum] – may help you with breathing difficulties
  3. Common mullein (flower) [Verbascum thapsus] – helps with breathing
  4. Marshmallow (root + aerial parts) [Althea officinalis]
  5. Linden (flower) [Tilia cordata]
  6. Chamomile (flower) [Matricaria recutita]

Don’t have any of the herbs listed? Chances are that your local herbs contain ursolic acid, chlorogenic acid, quercetin, kaempferol and rutin. Just make sure you do your research beforehand and don’t poison yourself. There are so many undiscovered wonders out there just like there are so many poisons.

In summary, there are several herbs that could be extremely good at treating not just the symptoms of coronavirus infection, but also its entry and replication. There is no guarantee that any of these will help you, but at least you would be proactively doing something to combat the infection as synthetic antivirals are still not very specific and may take a long time to research. All in all, prevention is still the best treatment.

If you enjoyed this article and would like to know more, please support the authors of the scientific studies that I referenced. Many of these are free and available to everyone, so reading the articles at the sites of the publishers helps.

References

1. Ho, T. Y., Wu, S. L., Chen, J. C., Li, C. C. & Hsiang, C. Y. Emodin blocks the SARS coronavirus spike protein and angiotensin-converting enzyme 2 interaction. Antiviral Res. 74, 92–101 (2007).

2. Cheng, L. et al. Citrus fruits are rich in flavonoids for immunoregulation and potential targeting ACE2. www.preprints.org (2020).

3. Zhang, L. & Liu, Y. Potential Interventions for Novel Coronavirus in China: A Systemic Review. J. Med. Virol. (2020) doi:10.1002/jmv.25707.

4. Luo, H. et al. Can Chinese Medicine Be Used for Prevention of Corona Virus Disease 2019 (COVID-19)? A Review of Historical Classics, Research Evidence and Current Prevention Programs. Chin. J. Integr. Med. 1–8 (2020) doi:10.1007/s11655-020-3192-6.

5. Yan, Y.-M. et al. Discovery of Anti-2019-nCoV Agents from 38 Chinese Patent Drugs toward Respiratory Diseases via Docking Screening. (2020) doi:10.20944/PREPRINTS202002.0254.V2.

6. Chhikara, B. S., Rathi, B., Singh, J. & FNU, P. Corona virus SARS-CoV-2 disease COVID-19: Infection, prevention and clinical advances of the prospective chemical drug therapeutics: A review on Corona Virus Disease COVID-19, epidemiology, prevention, and anticipated therapeutic advances. Chem. Biol. Lett. 7, 63–72 (2020).

7. Yan, Y.-M. et al. Discovery of Anti-2019-nCoV Agents from 38 Chinese Patent Drugs toward Respiratory Diseases via Docking Screening. (2020) doi:10.20944/PREPRINTS202002.0254.V2.

8. Cheng, J., Tang, Y., Bao, B. & Zhang, P. Exploring the Active Compounds of Traditional Mongolian Medicine Agsirga in Intervention of Novel Coronavirus (2019-nCoV) Based on HPLC-Q-Exactive-MS/MS and Molecular Docking Method. (2020) doi:10.26434/CHEMRXIV.11955273.V2.

9. Cui, H.-T. et al. Traditional Chinese medicine for treatment of coronavirus disease 2019: a review. Tradit. Med. Res. 5, 65–73 (2020).

10. Zhang, D., Wu, K., Zhang, X., Deng, S. & Peng, B. In silico screening of Chinese herbal medicines with the potential to directly inhibit 2019 novel coronavirus. J. Integr. Med. 18, 152–158 (2020).