Oregano is not just a tasty aromatic herb, it’s also been in use as a natural antiseptic since Ancient Greece. Added to meals, oregano supports heart health and antioxidant defense. It seems to be active against enveloped viruses in test tubes as well. The new coronavirus is enveloped, but do we know how oregano and its active compounds might affect it?
This article is for informational purposes only. The current coronavirus outbreak is an ongoing event and certain details may change as new information comes to light. No effective or FDA-approved products are currently available for the treatment of the new coronavirus (also known as SARS-CoV-2 or 2019-nCoV), although research is still ongoing. For now, the best preventive measures you can take against COVID-19 are standard precautions, including social distancing, hand washing, and avoiding touching your face.
Oregano Use Amid the COVID-19 Pandemic
Oregano is a plant from the same family as mint. Many oregano species exist, but the one you’re most likely to encounter in groceries and health stores is Origanum vulgare [1].
Besides being a culinary herb, oregano and its essential oil are packed with active compounds. Many of these are being researched for their medicinal properties, including antioxidant polyphenols and potentially microbe-fighting phenols (carvacrol and thymol) [2, 3].
Thanks to its nutrients and antioxidants, oregano is probably a good addition to any diet. People around the Mediterranean have been using it for millennia. Inhabitants of Ancient Greece and Rome, for example, used oregano as an antiseptic and wellness booster [4].
In the West, oregano essential oil has become a popular remedy during the cold and flu season. That doesn’t mean taking oregano can prevent or treat coronavirus, though. We can only gather clues from prior studies that tested oregano against viruses that are similar to the coronavirus strain we’re faced with right now.
How Oregano Affects Antioxidant Defense & Inflammation
Antioxidants support general health and immune function, potentially helping prevent chronic diseases. Staying healthy is paramount amid the current pandemic. Recent data reveal that healthy people are less likely to experience COVID-19 complications and die from it [5].
Oregano is rich in plant-based antioxidants. Even small doses of oregano (1 g/day) can provide a significant amount of these compounds, according to some studies. Its most important antioxidants are polyphenols like rosmarinic acid [6, 2, 7].
In one experiment on mice with colitis, essential oils of thyme and oregano reduced pro-inflammatory cytokines (IL-1β, and IL-6) [8].
Cytokines are mostly inflammatory messengers, and they seem to play a big role in COVID-19. The new coronavirus can cause life-threatening complications in later stages of infection by triggering “cytokine storms”–cytokine overload that wreaks inflammatory havoc in the body [9].
One cell-based study testing 71 herbal drugs from 63 plants ranked oregano as a strong anti-inflammatory. Oregano extract decreased pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) while boosting the anti-inflammatory cytokine IL-10 in another study [10, 11].
Additionally, oregano may enhance the bioavailability of other nutrients, but this hasn’t been confirmed in humans. In animals, oregano essential oil increased the surface area of the gut and reduced inflammation, which increases nutrient uptake [12].
Among the compounds found in oregano, thymol and carvacrol have the strongest antimicrobial activity [3, 13, 14].
In animals and cells, oregano essential oil and its active compounds inactivated viruses that cause [15, 16]:
- Contagious diarrhea and vomiting (murine norovirus)
- Cold-like symptoms and respiratory infections (respiratory syncytial virus)
- Gut and heart inflammation (coxsackievirus B3)
- Cold sores (herpes simplex virus type 1)
The last 3 viruses belong to a larger family of enveloped viruses. The 2019 coronavirus is the newest member of this family [5].
The fact that oregano oil was active against enveloped viruses is encouraging because envelopes help viruses stick to host cells. These tiny rod-like structures also make viruses much more aggressive and successful at invading cells (which is called viral infectivity). All coronaviruses, including the strain behind the pandemic, are enveloped [17].
Compounds that can disrupt envelopes like oregano might prevent coronaviruses from entering cells, but this has yet to be properly tested [18].
However, oregano had only mild activity against a coronavirus strain that causes bronchitis in birds. Other herbs like mint and thyme were more effective [19].
Have in mind that the new coronavirus also has other structures floating in its membrane that enable it to invade cells and spread (like “spike proteins” bound to envelopes). These are also targets for new therapies [20, 5].
Respiratory Infections
In a clinical trial on 60 people with upper respiratory tract infections, a spray with the essential oils of 5 aromatic plants (Syrian oregano, southern blue gum, lemon-scented gum, peppermint, and rosemary) improved the symptoms after 20 minutes [21].
Secondary Bacterial Infections
Bacterial superbugs are a growing COVID-19 issue. In one study, one in 7 hospitalized COVID-19 patients developed a secondary bacterial infection and half of them died [22].
Oregano extract blocked a well-known hospital superbug (methicillin-resistant Staphylococcus aureus or MRSA) in test tubes. In the same study, an ointment with 20% oregano inhibited two other bacteria that cause urinary tract and hospital-acquired infections (Proteus mirabilis and Proteus vulgaris) [23].
In another test-tube study examining 29 herbs against multi-drug resistant bacterial strains causing sore throat (Staphylococcus aureus and Pseudomonas aeruginosa), oregano was among the most active ones [24].
Some scientists believe silver nanoparticles may enhance the activity of oregano oil. This combination quickly killed a wide range of bacteria (including antibiotic-resistant strains) in test tubes; certain species were killed in as little as 20 minutes [25].
However, oregano hasn’t been tested against any of these bacteria in humans.
High blood pressure and heart disease are among the biggest risk factors for COVID-19 complications and death. The virus itself can also cause heart damage in hospitalized patients [26, 27].
Oregano might support heart health by balancing lipid levels, but additional clinical trials are needed to confirm this.
In one clinical trial on 48 people with mildly high blood fat levels, Cretan oregano (Origanum onites) extract taken after meals lowered “bad” LDL cholesterol while increasing “good” HDL cholesterol [28].
A meal rich in oregano and other spices (black pepper, cinnamon, cloves, paprika, rosemary, ginger, and turmeric) also reduced the high blood triglyceride levels in another study [29].
Dosage & Precautions
Dosage
The recommended dosage of oregano/its essential oil varies. Using roughly 1 g/day of the dried herb may provide enough antioxidants [30].
Doses used in clinical trials were:
- Antioxidant effects: 25 mL extract after meals or 300-600 mg/day phenolic compounds [28, 31]
- High blood cholesterol: 25 mL extract after meals [28]
Precautions & Side Effects
Oregano is generally safe when consumed in typical amounts used for cooking. Similarly, no health risks have been associated with oregano extract or oregano essential oil at normal doses. However, some studies caution that plant-based oils can be toxic at very high doses [32].
Takeaway
As an aromatic herb, oregano is packed with antioxidants and microbe-fighting compounds. However, it was never tested on the new coronavirus.
Oregano was active against some viruses in test tubes, although its antiviral activity has not been confirmed in humans.
Adding generous amounts of dried oregano to your meals might still be a good idea, though. Limited human studies reveal that oregano may help boost antioxidant defense and heart health. This could be important amid the current pandemic, as staying healthy might reduce your chance of serious COVID-19 complications.
