Wherever you are in the world, nature is abounding with health-sustaining plant chemicals … not far from your doorstep. Below is just a small selection of the many wild plants that can help boost overall respiratory health during this critical time, especially when taken in conjunction with other immune stimulants and antivirals like echinacea, elderberry and vitamin D.
Please note that the information given here is not intended as a substitute for conventional medical guidance on the treatment of COVID-19. The up-to-date official medical guidelines can be found online in the Internet Book of Critical Care. However, herbs are being trialled in China as first-line treatments for the virus and, while few herbalists outside of China have much experience treating the infection, it seems that it may be treated similarly to influenza and other respiratory infections.
Rock Rose (Cistus spp.)
This undervalued Southern European herb is a powerhouse of medicinal activity. Gum cistus or Cistus ladanifer boasts long sticky leaves dripping with resinous sap known as ‘labdanum’ which is incredibly healing to membranes of both the digestive and respiratory tracts.
Cistus species can be used to heal gastritis, ‘leaky gut’ or intestinal permeability, and chronic bacterial, fungal or viral infections. Most research has been done on Cistus incanus, a hybrid of C. albidus and C. crispus with very promising effects – it has shown activity against HIV, Ebola, Lyme/Borrelia, Candida and Aspergillus (common mould) infections. It has also been shown to inhibit the growth of bacteria and bacterial biofilms – the presence of which is a major contributor to chronic disease.
Most importantly, it has also shown antiviral activity against influenza A and rhinoviruses specifically, so it could be especially indicated for Covid-19 infection. It improves viral outcomes by targeting the envelope proteins on viral capsules, preventing them from attaching to host cells and replicating. A Cistus extract reduced common cold symptoms in one trial of 300 people, and decreased both symptoms and inflammatory biomarkers in another trial of 160 patients with upper respiratory tract infections.
The best way to use Cistus – any species is fine though I prefer C. ladanifer because of its incredible smell – is to make a tea from the fresh or dried leaves and take 2-3 cups daily, increasing that during an infection.
Nasturtium (Tropaeolum majus)
It’s the spicy kick which gives you a clue to Nasturtium’s properties – similar to watercress and rocket, the peppery compounds are called isothiocyanates and are powerful antibiotic substances.
However, the importance of nasturtium in cold and flu prevention comes more from its rich micronutrient content, in my opinion. The leaves and flowers contain large amounts of vitamin C, as well as zinc and iron. These nutrients, along with selenium (brazil nuts, fish and eggs) and vitamin A (liver, cod liver oil or in vegetables as beta-carotene) are crucial for the maintenance of a healthy immune system.
Taken as a tea or extract, nasturtium is a stimulating expectorant for the lungs – it is heating, and helps draw out stuck phlegm by irritating the membranes of the respiratory tract. This isn’t necessarily indicated during Covid-19 infection due to the predominance of dry cough – however, fresh nasturtium leaves have a demulcent quality to them, and feel quite soothing on the throat. So, stick to the fresh leaves – that way you’ll also be getting the micronutrients in their whole bioavailable form.
Olive leaf (Olea europaea)
Just like Cistus species, olive leaf has been shown to have broad-spectrum antimicrobial properties with activity against bacteria, fungi, parasites and viruses, including the influenza virus. Oleuropein, one constituent of olive leaf, is thought to interact with proteins on the virus capsule much like Cistus, and thereby interfere with its replication and invasion of host cells.
Olive leaf has also been effective in clinical studies – an extract containing 20g olive leaf, when given to 32 high school athletes for nine weeks during their competitive season, produced a 28% reduction in sick days compared to the control group.
However, the potential benefits of olive leaf in preventing and treating Covid-19 go beyond its antiviral effects. Every day we hear that the overwhelming number of people lost to this virus have either one, two or three co-morbidities (pre-existing illnesses) – namely high blood pressure, cardiovascular disease and diabetes. Olive leaf has been shown in clinical studies to lower systolic and diastolic blood pressure, improve blood sugar control and reduce the oxidation of cholesterol molecules – all factors which contribute to a healthy metabolic and cardiovascular system.
Fresh olive leaves make a very mild, pleasant-tasting tea that can be consumed alone or with Cistus leaves for an all-round anti-infectious, immune-boosting drink.
By Poppy Burr
Poppy is a UK-trained medical herbalist practising in Praia da Luz. She offers consultations and treatment in Western Herbal Medicine, incorporating Functional Medicine testing and nutritional strategies where appropriate. For more information, visit poppytheherbalist.com