Ayurvedic Herb Rosemary May Block COVID-19 Infection: Study

A preliminary study has proposed carnosic acid, a compound found in rosemary, as a potentially cheap, safe, and effective treatment for COVID-19 and some other inflammation-related disorders.

Rosemary, or Rosmarinus officianalis, is an aromatic evergreen shrub that is native to the Mediterranean. It is widely used as a culinary condiment all over the world, and in the manufacturing of soaps, perfumes, skin and hair care products. Also known for its medicinal properties, rosemary is used in traditional herbal and Ayurveda medicine for treating tons of health conditions. Now, a preliminary study has suggested that a compound found in the herb may potentially block the novel coronavirus virus, and prevent inflammation caused by COVID-19.

The study, recently published in the journal Antioxidants, found that carnosic acid, a compound present in rosemary, can block the interaction between the SARS-CoV-2 spike protein and the receptor protein ACE2. SARS-CoV-2 virus binds to ACE2 to enter the host cells.

Further, a review of prior studies also showed that carnosic acid can potentially inhibit a powerful inflammatory pathway that is active in severe COVID-19 and other diseases like Alzheimer's.

Study senior author Stuart Lipton, a professor at Scripps Research in the US, think that it is worth investigating carnosic acid, or some optimised derivative, as a potentially cheap, safe, and effective treatment for COVID-19 and some other inflammation-related disorders.

Carnosic acid in rosemary has antiviral, anti-inflammatory effects

In their previous study conducted in 2016, Lipton and colleagues had found that carnosic acid in rosemary activates an anti-inflammatory, antioxidant signalling pathway called the Nrf2, which reduces Alzheimer's-like signs in mouse models.

For the new study, Lipton collaborated with researchers from the Tokyo University of Technology, Japan, to examine this anti-inflammatory effect on the immune cells that drive inflammation in COVID-19 and Alzheimer's.

They found that carnosic acid can directly block SARS-CoV-2's ability to infect cells, and this infection-blocking activity progressively increases at higher doses.

Although carnosic acid is a relatively unreactive compound in its normal state, it can convert to an active form where it needs to be active. The compound gets converted to its active form by the inflammation and oxidation found at sites of infection. Once it is in its active form, carnosic acid modifies the ACE2 receptor for SARS-CoV-2 -- making the receptor impregnable to the virus and thereby blocking infection, the researchers explained.

While the finding is preliminary, the researchers believe that carnosic acid has antiviral effects, and it could be beneficial in the treatment for COVID-19 and some other inflammation-related disorders.

The researchers are working to synthesise and test more potent derivatives of carnosic acid with improved drug characteristics for potential use in inflammation-related disorders.

Uses of Rosemary in Ayurvedic treatments

Rosemary is known as Rujamari in Ayurveda. Rosemary essential oil is used in ayurvedic treatments for boosting memory; treating headaches, stomach upset, insect bites, skin problems like eczema and skin infections; management stress and depression; as well as in aromatherapy.

Owing to its antioxidant property, rosemary oil is known to be beneficial for skin and helps prevent wrinkles and signs of aging. It improves the circulation of blood in the scalp and promotes hair growth. Thanks to its anti-inflammatory properties, rosemary oil is believed to help ease joint pain.