With COVID cases and hospital admissions at record highs in Australia, there seems to be no end to this pandemic. The ongoing problem of new variants and diminishing protection from vaccination is further compounded by apathy or antipathy amongst the public in the face of increasing statistics of re-infection.

After two years of lockdowns, curfews, QR codes, compulsory medicine and other public control measures backed by extraordinary police powers, the authorities now appear strangely reluctant to enforce the most basic and yet most effective health measures such as hand washing, masks and social distancing.

We should continue to follow these measures but also take steps to bolster our immune systems and manage stress as best we can, before getting sick and relying on antivirals such as molnupiravir and paxlovid. After all, this is not a simple cold or flu, and neither vaccination boosters nor antiviral drugs will protect us against the devastating effects of long-COVID.

A basic wholefood diet, regular exercise and adequate rest are part of an alternative preventative strategy that does not necessarily exclude vaccination. In addition, we should investigate the potential of superfoods, clinical nutrients and powerful medicinal herbs to be used as prophylactics, as well as for treatment if we should catch the virus.

Liquorice (Glycyrrhiza glabra) is an example of just such a valuable herb attracting a lot of scientific attention for potential COVID treatment. It is, in fact, a traditional medicinal herb with thousands of years of recorded usage by Chinese, Egyptian, Greek, Roman and Indian physicians. They used it to treat many complaints particularly those of the respiratory and digestive systems because of its soothing anti-inflammatory activity. Modern research has established that it has anticancer, antioxidant, antitussive, anti-asthmatic, immunomodulatory, hypoglycaemic, neuroprotective and hepatoprotective properties in addition, as well as being antibacterial and antiviral in activity.¹

It is the antiviral activity that medical scientists are focusing on. In fact, compounds in the herb (glycyrrhizin, glycyrrhetinic acid, liquirtin) have been found to possess activity against several viruses including herpes virus, hepatitis, influenza, Epstein-Barr, Pseudorabies, Varicella-zoster, HIV, as well as SARS-CoV coronaviruses. The effect of glycyrrhizin on SARS-CoV-2 (COVID-19), in particular, is to significantly prevent virus replication.^2,3

The mechanism by which ‘multi-target’ compounds in liquorice are active against COVID  is by ‘interacting with various viral and cellular processes important for viral internalization and replication.’ These include interference with spike-mediated processes within the host cell (S, M) and within the membrane (serine protease 2, and 3-chymotrypsin-like cysteine protease). They also down-regulate ACE2 cell receptors required for virus docking, induce inflammatory processes (corticosteroid-like activity), as well as display anti-oxidant activity.³

With all this potential you would imagine that there would be several clinical trials underway using liquorice herb or extracts for the treatment of COVID; however, so far there is mostly just speculation. Nevertheless, apart from the many protective actions this herb has on immune defences, when used in combination with other herbs, liquorice will enhance their activity. It follows that Liquorice could be used in combination with other herbs that have potential for treatment against COVID such as garlic,⁴ echinacea,⁵ turmeric,⁶ or Boswelia.⁷

An example of liquorice extract in combination with Boswelia is a recent randomised clinical trial of 50 COVID patients at Sohag University hospital Egypt, who were given combination treatment with a capsule containing 60mg glycyrrhizin and 200mg Boswellic acids. The trial group was compared to placebo for fourteen days with the result that C-reactive protein (CRP), and inflammation marker, was significantly reduced; there was a significantly faster recovery time; and there were no deaths in the treatment group, compared to several in the placebo group.^8,9

As a warning, compounds in liquorice (glycyrrhizic acid, glycyrrhizinate, glycyrrhetinic acid) will raise blood pressure and may cause hypokalaemia when consumed in large quantities—tea or confectionary—due to the activation of renal mineralocorticoid receptors by elevated cortisol. For patients with high blood pressure we can use deglycyrrhizinated liquorice (DGL) instead.^10,11

Special:

If you would like to know more about medicinal herbs and wholefoods an A-Z eBook is available (Amazon, Kobo) which is comprised of essays with references from traditional herbals as well as the current medical evidence-base. Many of these essays are also available free on this website in abridged form under the wholefoods and herbs tab.

Disclaimer:

This article is intended for the purpose of general education only, and is not a substitute for a diagnosis, treatment advice, or a prescription given in a consultation with a qualified physician.

References:

1.         Bisht D, Rashid M, Arya RKK, et al. Revisiting liquorice (Glycyrrhiza glabra L.) as anti-inflammatory, antivirals and immunomodulators: Potential pharmacological applications with mechanistic insight. Phytomed Plus 2022;2:100206.

2.         Huan C, Xu Y, Zhang W, Guo T, Pan H, Gao S. Research Progress on the Antiviral Activity of Glycyrrhizin and its Derivatives in Liquorice. Front Pharmacol 2021;12:680674.

3.         Diomede L, Beeg M, Gamba A, Fumagalli O, Gobbi M, Salmona M. Can Antiviral Activity of Licorice Help Fight COVID-19 Infection? Biomolecules 2021;11:855.

4.         Khubber S, Hashemifesharaki R, Mohammadi M, Gharibzahedi SMT. Garlic (Allium sativum L.): a potential unique therapeutic food rich in organosulfur and flavonoid compounds to fight with COVID-19. Nutr J 2020;19:124.

5.         Nagoor Meeran MF, Javed H, Sharma C, et al. Can Echinacea be a potential candidate to target immunity, inflammation, and infection – The trinity of coronavirus disease 2019. Heliyon 2021;7:e05990.

6.         Chen L, Hu C, Hood M, et al. A Novel Combination of Vitamin C, Curcumin and Glycyrrhizic Acid Potentially Regulates Immune and Inflammatory Response Associated with Coronavirus Infections: A Perspective from System Biology Analysis. Nutrients 2020;12.

7.         Caliebe RH, Scior T, Ammon HPT. Binding of boswellic acids to functional proteins of the SARS‐CoV‐2 virus: Bioinformatic studies. Arch Pharm (Weinheim) 2021;354:2100160.

8.         Gomaa AA, Mohamed HS, Abd-Ellatief RB, Gomaa MA, Hammam DS. Advancing combination treatment with glycyrrhizin and boswellic acids for hospitalized patients with moderate COVID-19 infection: a randomized clinical trial. Inflammopharmacology 2022;30:477–86.

9.         Fatima SW, Alam S, Khare SK. Molecular and structural insights of β-boswellic acid and glycyrrhizic acid as potent SARS-CoV-2 Envelope protein inhibitors. Phytomed Plus 2022;2:100241.

10.       Sontia B, Mooney J, Gaudet L, Touyz RM. Pseudohyperaldosteronism, liquorice, and hypertension. J Clin Hypertens (Greenwich) 2008;10:153–7.

11.       Kwon YE, Oh D-J, Choi HM. Severe asymptomatic hypokalemia associated with prolonged licorice ingestion: A case report. Medicine (Baltimore) 2020;99:e21094.