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Tulsi leaf, also known as holy basil, has emerged as one of the most sacred medicinal plants in India. It has been used for thousands of years in Ayurvedic medicine to support and strengthen the body, and it is thought to help manage and treat a wide range of health conditions.

What Is Tulsi Leaf?

Tulsi leaf is one of the most useful parts of the tulsi plant. Tulsi is Ocimum sanctum, a leafy, aromatic herb that’s native to India. In Hindu, it's known as the “Queen of Herbs” or the “Incomparable One.” In Hinduism, the plant is worshipped as a goddess.

In traditional Indian or Ayurvedic medicine, the most useful parts of the tulsi plant include the leaves, roots, stem, flowers and even the oil.

The leaves and roots are often used for medicinal purposes, but many parts of the plant also have non-medicinal uses. The roots are important in making “holy water,” which is used to sanctify the home, while the stems or seeds are used to make beads, which are worn to help the mind focus. The essential oils derived from this plant help repel insects.

While all parts are considered sacred, the leaf is particularly valuable as it’s added to traditional Indian dishes or consumed in the form of tea as both a morning and evening ritual in Hinduism.

Tulsi in Ayurvedic Medicine

Ayurvedic medicine has long appreciated the importance of tulsi for treating a wide range of medical conditions and even for promoting longevity. According to a review published in February 2018 in the Journal of Medicinal Plants Studies, Ayurvedic medicine uses for tulsi leaf as well as other parts of the plant include:

  • Reducing, pain, swelling and inflammation
  • Improving skin disorders and minimizing itching or rash, acne or scars
  • Alleviating headaches and head and neck conditions
  • Treating indigestion, constipation and intestinal parasites
  • Reducing fever, cough, bronchitis, or any upper respiratory infections
  • Strengthening the heart and purifying the blood

In addition to treating these conditions, Ayurvedic medicine has long stressed the importance of tulsi as one of many adaptogenic herbs.

A June 2017 review published in the_ Annals of the New York Academy of Sciences _describes adaptogens — which include foods, spices and medicinal herbs — as metabolic regulators that help the body adapt to and avoid damage from environmental stressors. Tulsi leaf may increase resilience to stress, whether it has mental or physical causes.

May Reduce Chronic Disease Risk

Over the past few decades, scientists have studied the chemical constituents and pharmacological effects of tulsi. Researchers have identified numerous compounds within the plant that are likely associated with its health benefits.

Research published in the Journal of Bioequivalence and Bioavailability in April 2017 states that eugenol is the most important compound in the plant, but there are also other phytochemicals from health-promoting essential oils, fatty acids, plant sterols, polyphenol antioxidants and vitamins A and C in every part of the tulsi plant.

These compounds likely work together and are responsible for the role of tulsi in regulating health and preventing chronic diseases. Most of the research on its benefits comes from animal studies or small studies on people, but the results are promising.

According to a study published in the January 2012 issue of the Journal of Natural Remedies, 5 milliliters of tulsi leaf extract taken twice a day for three months reduced blood sugar, blood pressure and cholesterol in people with metabolic syndrome.

An October 2016 review on Ayurvedic plants, published in the Journal of Evidence-Based Integrative Medicine, has found evidence that when used along with medications for these metabolic conditions, tulsi seems to have a complementary effect. That suggests that one might be able to use fewer medications or lower doses.

Some of the compounds in tulsi leaf also have anti-cancer properties. The above review mentions that lab and animal studies have found that extracts from the tulsi plant were effective in slowing cancer cell growth and reducing tumor size in lung and sarcoma (bone and soft tissue) cancers.

Tulsi Has Antimicrobial Benefits

Many of tulsi’s traditional uses include fighting infections, viruses and parasites. Recent research has confirmed that the plant does indeed have antimicrobial properties. The essential oils in tulsi, especially eugenol, may inhibit the growth of several dangerous pathogens.

Some of these pathogens include bacteria such as: E. coli, Salmonella, Shigella and Vibrio, which are usually contracted via foodborne illnesses, as well as Proteus mirabilis, which causes urinary tract infections, Klebsiella, which may cause wound or blood infections, and Staphylococcus aureus, which may trigger gastrointestinal, upper respiratory and skin infections. The most serious form of S. aureus is Methicillin-resistant Staphylococcus aureus (MRSA).

Researchers tested the effects of tulsi extract against the bacteria Klebsiella pneumoniae and Staphylococcus aureus. They found that an alcohol extract of the plant was just as effective as synthetic antibiotics against this bacterium. The results were published in the November 2018 edition of the Journal of Drug Delivery and Therapeutics.

Read more: Signs and Symptoms of Bacterial Infection

May Promote Healthy Stress Response

In addition to these health benefits, tulsi and other adaptogenic herbs have been studied for their effects on stress. It’s thought that one of the adaptogenic functions of tulsi is to help regulate the hypothalamic-adrenal-pituitary (HPA) axis and promote a healthier stress response in individuals.

Again, much of the research in this area comes from lab and animal studies, including the one published in May 2016 in the journal Phytotherapy Research. Scientists tested the effects of tulsi extract on rats exposed to varying degrees of chronic stress, similarly to what humans might experience. Researchers have found that the mice treated with tulsi extract were better able to manage the stress and also had lower levels of cortisol, the “fight-or-flight” hormone.

Managing one’s stress is an important focus of functional medicine. It’s thought that day-to-day stress takes a toll on health by disrupting hormonal balance, impacting sleep and weakening the immune system.

Read more: These Stress-Fighting Adaptogens Are the New Superfoods

Using tulsi leaf in capsule form or tincture or sipping it in the form of a tea may help strengthen the body in various ways and improve your health. It’s considered to be a safe supplement with few reported side effects. However, if you think you might benefit from tulsi, first talk to your healthcare provider to make sure it's safe and effective for you and won’t interact with any medications.

About the Author

Anne Danahy MS RDN

Anne Danahy is a Boston-based RD/nutritionist who counsels individuals and groups, and writes about healthy eating for wellness and disease management. She holds a Bachelor of Arts from the University of Notre Dame, and a Master of Science in food and nutrition from Framingham State University in Massachusetts.