Holy basil (Ocimum tenuiflorum), also known as tulsi, is a perennial plant that is native to the Indian subcontinent. It is closely related to the sweet basil plant widely used in cooking. Holy basil contains many different constituents, including camphor, eucalyptol, eugenol, alpha and beta bisabolene, and beta caryophyllene, all of which are thought to have antimicrobial effects. The chemical constituent, eugenol, is thought to exert anticancer effects (), also known as tulsi, is a perennial plant that is native to the Indian subcontinent. It is closely related to the sweet basil plant widely used in cooking. Holy basil contains many different constituents, including camphor, eucalyptol, eugenol, alpha and beta bisabolene, and beta caryophyllene, all of which are thought to have antimicrobial effects. The chemical constituent, eugenol, is thought to exert anticancer effects (1).
Claims for Holy Basil
Holy basil is considered an adaptogen, which means it is thought to help the body respond to stress and restore normal function (2). Holy basil is claimed to:
Reduce anxiety and stress
Lower blood glucose in people with diabetes
Lower cholesterol levels
Provide protection from bacterial and viral infections
Promote wound healing
Reduce inflammation
Holy basil seems to be safe for most people when taken by mouth for up to 8 weeks. The safety of taking holy basil for longer than 8 weeks has not been studied.
Evidence for Holy Basil
There are few high-quality studies in humans demonstrating that holy basil is effective for treating any health condition. One randomized trial comparing holy basil to placebo in 100 adults showed improvement in perceived various scale scores related to stress and sleep (3). In addition, a small controlled cross-over study of holy basil and placebo in 40 patients showed improvement in fasting and postprandial blood glucose (4). Another 90-day study of 60 patients compared glibenclamide (a sulfonylurea) monotherapy to combination glibenclamide plus holy basil. The study demonstrated slightly more improvement in fasting and postprandial glucose levels and hemoglobin A1C levels in the combination therapy group (5).
Adverse Effects of Holy Basil
Holy basil can have adverse effects such as nausea or diarrhea.
Holy basil might not be safe when taken by women who are pregnant or trying to become pregnant. In animal studies, large doses of holy basil reduced the chance that a fertilized egg would become attached to the uterus and that the pregnancy would last for a full term. Whether these effects happen in humans is not known, but anyone trying to conceive should be advised to avoid its use. The safety of holy basil in women who breastfeed their babies has not been studied.
Holy basil might decrease levels of the thyroid hormone thyroxine, worsening hypothyroidism.
Holy basil appears to inhibit platelet aggregation and prolong clotting times, which may increase the risk of bleeding during and after surgery.
Drug Interactions with Holy Basil
Holy basil may decrease the efficacy of thyroid hormone medications.
The effect of holy basil to slow down blood clotting may increase the risk of bleeding in people taking antiplatelet or anticoagulation medications. Per animal data, holy basil may also enhance the sedating effects of barbiturates.
(See also table Some Possible Dietary Supplement–Medication Interactions.)
References
1. Hasan MR, Alotaibi BS, Althafar ZM, Mujamammi AH, Jameela J. An Update on the Therapeutic Anticancer Potential of Ocimum sanctum L.: "Elixir of Life". Molecules. 2023 Jan 25;28(3):1193. doi: 10.3390/molecules28031193
2. Cohen MM. Tulsi - Ocimum sanctum: A herb for all reasons. J Ayurveda Integr Med. 2014 Oct-Dec;5(4):251-9. doi: 10.4103/0975-9476.146554
3. Lopresti AL, Smith SJ, Metse AP, Drummond PD. A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (HolixerTM) on stress, mood, and sleep in adults experiencing stress. Front Nutr. 2022 Sep 2;9:965130. doi: 10.3389/fnut.2022.965130
4. Agrawal P, Rai V, Singh RB. Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus. Int J Clin Pharmacol Ther. 1996 Sep;34(9):406-9
5. Somasundaram G, Manimekalai K, Salwe KJ, Pandiamunian J. Evaluation of the antidiabetic effect of Ocimum sanctum in type 2 diabetic patients. Int J Life Sci Pharma Res.2012;2(3):P75–P81.
