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Holy Basil

Medically reviewed on August 13, 2018

Scientific Name(s): Ocimum tenuiflorum L. (Syn: Ocimum sanctum L.) Family: Lamiaceae (mint)

Common Name(s): Holy basil , ajaka , baranda , brinda , kha phrao , manjari , monk's basil , parnasa , patra-puspha , sacred basil , suvasa , Thai basil , thulasi , tulasi , tulsi


Clinical trials are lacking. In animal and in vitro experiments, effects of holy basil are largely attributed to antioxidant activity. Hypoglycemic activity and protective effects against noise stress have been studied, but clinical trials are lacking.


Information is lacking. One clinical trial for hypoglycemic effect used 2.5 g leaves as dried powder in 200 mL water daily for 2 months.


None established.


Information regarding safety and efficacy in pregnancy and lactation is lacking.


None well documented.

Adverse Reactions

Information is lacking.


Information is limited. Reversible inhibition of spermatogenesis, and decreased total sperm count and motility have been demonstrated in mice.


O. tenuiflorum is a perennial and many-branched shrub that can grow to 1 m high. Green and purple color variants exist that are otherwise morphologically indistinguishable. The proportions of chemical constituents may differ according to chemotype and geographical variation.

Unlike common basil, holy basil plants have slightly hairy, pale leaves that are simple, opposite, and oblong or ovate, measuring 3 to 7 cm long and 1 to 3 cm wide. The leaves have a characteristically strong aroma, likened to cloves, and an astringent taste. The flowering part of the plant consists of a florescence of purple and red flowers. 1 , 2 , 3


The use of tulsi (holy basil) is recorded in ancient Ayurvedic texts and the plant is an important symbol in Hindu religious tradition. Holy basil has been described as an elixir of life and a tonic with adaptogenic properties, and has also been promoted for longevity. It is used for treating the common cold, headaches, stomach complaints, inflammation, heart disease, poisoning, and malaria. Holy basil is used in cooking and consumed as a fresh leaf, as well as an herbal tea, dried powder, or mixed with ghee. The dried leaves are stored with grains as an insect repellent and the essential oil is used in cosmetics and skin preparations. 2 , 3


O. tenuiflorum primarily contains tannins, flavonoids, and an essential oil. Traces of zinc, manganese, and sodium have been found, as well as vitamins A and C. 4 Gas chromatography-mass spectrometry has been used to elucidate the constituents of the essential oil: eugenol and methyl eugenol (up to 64%), alpha and beta-caryophyllene, carvacrol, linalool, germacrene A, beta-ocimene, and cinnamyl acetate. Other constituents include oleanolic acid, rosmarinic acid, ursolic acid, apigenins, luteolins, cerebrosides, and acimumosides. 2 , 3 , 4 , 5 , 6

Uses and Pharmacology

Despite a long traditional use of holy basil for medical conditions, clinical trials are lacking. Many effects are attributed to antioxidant action of the extracts and individual chemical constituents. 7 , 8 , 9 , 10 , 11 , 12

CNS effects

Experiments in rats have demonstrated a protective effect of holy basil extracts against noise stress. Noise-induced increases in circulating corticosterone, dopamine, and serotonin levels were prevented with holy basil extract pretreatment, and other adaptogenic effects on biochemical changes in acetylcholine, acetycholinesterase, and creatine kinase were observed. 4 , 11 , 13 , 14 , 15 , 16

Analgesic and anticonvulsant actions have been described in animals, as well as attenuation of the effects of cerebrovascular insufficiency, and induced axonal degeneration and memory deficits. 2 , 12 , 17 , 18

Hypoglycemic effect

A Cochrane review of the use of traditional plants in hyperglycemia found a hypoglycemic response to holy basil versus placebo in 1 small trial (N = 40). However, poor methodological quality was noted related to inadequate blinding and randomization, and no trials compared holy basil with pharmacological agents. 19 A role in the management of metabolic syndrome has been suggested considering improved lipid profiles, antioxidant and cardioprotective effects demonstrated in animal experiments, 20 , 21 in addition to observed hypoglycemic effects. 2 , 4 , 22 , 23 Suggested mechanisms include insulin-secretory effects and reductions in insulin resistance, and enhanced activity of glucokinase, hexokinase, and phosphofructokinase enzymes. 4 , 21 , 22 , 23

Other effects

Extracts of holy basil, particularly those containing eugenol, have shown in vitro activity against a number of microorganisms including resistant strains of Neisseria gonorrhoeae . 2 , 24 , 25


Experiments in animals found extracts of holy basil to be protective against radiation-induced DNA damage, probably by antioxidant mechanisms. 10 , 26 , 27 , 28 , 29 Protective effects were demonstrated against induced gastric cancer with concomitant introgastric administration of holy basil extract 30 and against induced skin-tumorigenesis with topical application of the extract. 31


Animal studies with induced ulcers have shown protective and healing properties with use of the extracts and fixed oil of holy basil. Suggested mechanisms of action include antioxidant action, lipoxygenase inhibition, histamine antagonism, and antisecretory effects. 2 , 32 , 33 , 34 , 35


Conflicting data exist regarding the cardioprotective properties of holy basil extracts. Positive histological and biochemical marker findings have been reported in some animal experiments. 36 , 37 Reduction in lipid peroxidation also has been demonstrated. 7 , 21 Clinical trials are lacking.


Clinical trials are lacking to support dosages. One clinical trial used 2.5 g holy basil leaves as dried powder in 200 mL water daily for 2 months for hypoglycemic effect. 19


Information regarding safety and efficacy in pregnancy and lactation is lacking. Conflicting data exist regarding the embryotoxicity of O. tenuiflorum , with some experiments in rats showing toxicity at 100 to 200 mg/kg body weight while others have shown no toxicity. 2

Traditional use of holy basil to enhance lactation has been recorded, but safety data are lacking. 2


Case reports are lacking. Potentiation of the sedative effects of barbiturates has been demonstrated in experiments in rats. 2 , 17 Eugenol was observed to be hepatotoxic in glutathione-depleted mice, leading to a cautionary note on the concomitant use of acetaminophen. 2

Adverse Reactions

Data are limited. Few adverse reactions were noted in a Cochrane review of holy basil studies. 19


Information is limited. Reversible inhibition of spermatogenesis and decreased total sperm count and motility have been demonstrated in mice administered extracts of the plant. 2 , 38


1. Holy basil . USDA, NRCS. 2008. The PLANTS Database ( , March 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. Folium Ocimi Sancti. In: WHO Monographs on Selected Medicinal Plants . Vol 1. Geneva, Switzerland: World Health Organization; 1999: 207-216.
3. Kothari SK, Bhattacharya AK, Ramesh S. Essential oil yield and quality of methyl eugenol rich Ocimum tenuiflorum L.f. (syn. O. sanctum L.) grown in south India as influenced by method of harvest. J Chromatogr A . 2004;1054(1-2):67-72.
4. Gupta P, Yadav DK, Siripurapu KB, Palit G, Maurya R. Constituents of Ocimum sanctum with antistress activity. J Nat Prod . 2007;70(9):1410-1416.
5. Trevisan MT, Vasconcelos Silva MG, Pfundstein B, Spiegelhalder B, Owen RW. Characterization of the volatile pattern and antioxidant capacity of essential oils from different species of the genus Ocimum. J Agric Food Chem . 2006;54(12):4378-4382.
6. Hakkim FL, Shankar CG, Girija S. Chemical composition and antioxidant property of holy basil ( Ocimum sanctum L.) leaves, stems, and inflorescence and their in vitro callus cultures. J Agric Food Chem . 2007;55(22):9109-9117.
7. Geetha RK, Vasudevan DM. Inhibition of lipid peroxidation by botanical extracts of Ocimum sanctum : in vivo and in vitro studies. Life Sci . 2004;76(1):21-28.
8. Sharmila Banu G, Kumar G, Murugesan AG. Effects of leaves extract of Ocimum sanctum L. on arsenic-induced toxicity in Wistar albino rats. Food Chem Toxicol . 2009;47(2):490-495.
9. Manikandan P, Murugan RS, Abbas H, Abraham SK, Nagini S. Ocimum sanctum Linn. (Holy Basil) ethanolic leaf extract protects against 7,12-dimethylbenz(a)anthracene-induced genotoxicity, oxidative stress, and imbalance in xenobiotic-metabolizing enzymes. J Med Food . 2007;10(3):495-502.
10. Subramanian M, Chintalwar GJ, Chattopadhyay S. Antioxidant and radioprotective properties of an Ocimum sanctu m polysaccharide. Redox Rep . 2005;10(5):257-264.
11. Samson J, Sheeladevi R, Ravindran R. Oxidative stress in brain and antioxidant activity of Ocimum sanctum in noise exposure. Neurotoxicology . 2007;28(3):679-685.
12. Muthuraman A, Diwan V, Jaggi AS, Singh N, Singh D. Ameliorative effects of Ocimum sanctum in sciatic nerve transection-induced neuropathy in rats. J Ethnopharmacol . 2008;120(1):56-62.
13. Archana R, Namasivayam A. A comparative study of different crude extracts of Ocimum sanctum on noise stress. Phytother Res . 2002;16(6):579-580.
14. Samson J, Sheela Devi R, Ravindran R, Senthilvelan M. Biogenic amine changes in brain regions and attenuating action of Ocimum sanctumin noise exposure. Pharmacol Biochem Behav . 2006;83(1):67-75.
15. Ravindran R, Rathinasamy SD, Samson J, Senthilvelan M. Noise-stress-induced brain neurotransmitter changes and the effect of Ocimum sanctum (Linn) treatment in albino rats. J Pharmacol Sci . 2005;98(4):354-360.
16. Sembulingam K, Sembulingam P, Namasivayam A. Effect of Ocimum sanctum Linn on the changes in central cholinergic system induced by acute noise stress. J Ethnopharmacol . 2005;96(3):477-482.
17. Khanna N, Bhatia J. Antinociceptive action of Ocimum sanctum (Tulsi) in mice: possible mechanisms involved. J Ethnopharmacol . 2003;88(2-3):293-296.
18. Yanpallewar SU, Rai S, Kumar M, Acharya SB. Evaluation of antioxidant and neuroprotective effect of Ocimum sanctum on transient cerebral ischemia and long-term cerebral hypoperfusion. Pharmacol Biochem Behav . 2004;79(1):155-164.
19. Liu JP, Zhang M, Wang WY, Grimsgaard S. Chinese herbal medicines for type 2 diabetes mellitus. Cochrane Database Syst Rev . 2004;(3):CD003642.
20. Kapoor S. Ocimum sanctum : a therapeutic role in diabetes and the metabolic syndrome. Horm Metab Re s. 2008;40(4):296.
21. Reddy SS, Karuna R, Baskar R, Saralakumari D. Prevention of insulin resistance by ingesting aqueous extract of Ocimum sanctum to fructose-fed rats. Horm Metab Res . 2008;40(1):44-49.
22. Vats V, Yadav SP, Grover JK. Ethanolic extract of Ocimum sanctum leaves partially attenuates streptozotocin-induced alterations in glycogen content and carbohydrate metabolism in rats. J Ethnopharmacol . 2004;90(1):155-160.
23. Hannan JM, Marenah L, Ali L, Rokeya B, Flatt PR, Abdel-Wahab YH. Ocimum sanctum leaf extracts stimulate insulin secretion from perfused pancreas, isolated islets and clonal pancreatic beta-cells. J Endocrinol . 2006;189(1):127-136.
24. Shokeen P, Bala M, Singh M, Tandon V. In vitro activity of eugenol, an active component from Ocimum sanctum , against multiresistant and susceptible strains of Neisseria gonorrhoeae . Int J Antimicrob Agents . 2008;32(2):174-179.
25. Shokeen P, Ray K, Bala M, Tandon V. Preliminary studies on activity of Ocimum sanctum , Drynaria quercifolia , and Annona squamosa against Neisseria gonorrhoeae . Sex Transm Dis . 2005;32(2):106-111.
26. Nayak V, Devi PU. Protection of mouse bone marrow against radiation-induced chromosome damage and stem cell death by the ocimum flavonoids orientin and vicenin. Radiat Res . 2005;163(2):165-171.
27. Vrinda B, Uma Devi P. Radiation protection of human lymphocyte chromosomes in vitro by orientin and vicenin. Mutat Res . 2001;498(1-2):39-46.
28. Siddique YH, Ara G, Beg T, Afzal M. Anti-genotoxic effect of Ocimum sanctum L. extract against cyproterone acetate induced genotoxic damage in cultured mammalian cells. Acta Biol Hung . 2007;58(4):397-409.
29. Dutta D, Devi SS, Krishnamurthi K, Kumar K, Vyas P, Muthal PL, Naoghare P, Chakrabarti T. Modulatory effect of distillate of Ocimum sanctum leaf extract (Tulsi) on human lymphocytes against genotoxicants. Biomed Environ Sci . 2007;20(3):226-234.
30. Manikandan P, Vidjaya Letchoumy P, Prathiba D, Nagini S. Proliferation, angiogenesis and apoptosis-associated proteins are molecular targets for chemoprevention of MNNG-induced gastric carcinogenesis by ethanolic Ocimum sanctum leaf extract. Singapore Med J . 2007;48(7):645-651.
31. Rastogi S, Shukla Y, Paul BN, Chowdhuri DK, Khanna SK, Das M. Protective effect of Ocimum sanctum on 3-methylcholanthrene, 7, 12-dimethylbenz(a)anthracene and aflatoxin B1 induced skin tumorigenesis in mice. Toxicol Appl Pharmacol . 2007;224(3):228-240.
32. Dharmani P, Kuchibhotla VK, Maurya R, Srivastava S, Sharma S, Palit G. Evaluation of anti-ulcerogenic and ulcer-healing properties of Ocimum sanctum Linn. J Ethnopharmacol . 2004;93(2-3):197-206.
33. Goel RK, Sairam K, Dorababu M, Prabha T, Rao ChV. Effect of standardized extract of Ocimum sanctum Linn. on gastric mucosal offensive and defensive factors. Indian J Exp Biol . 2005;43(8):715-721.
34. Kath RK, Gupta RK. Antioxidant activity of hydroalcoholic leaf extract of ocimum sanctum in animal models of peptic ulcer. Indian J Physiol Pharmacol . 2006;50(4):391-396.
35. Singh S, Majumdar DK. Evaluation of the gastric antiulcer activity of fixed oil of Ocimum sanctum (Holy Basil). J Ethnopharmacol . 1999;65(1):13-19.
36. Sood S, Narang D, Thomas MK, Gupta YK, Maulik SK. Effect of Ocimum sanctum Linn. on cardiac changes in rats subjected to chronic restraint stress. J Ethnopharmacol . 2006;108(3):423-427.
37. Mohanty I, Arya DS, Gupta SK. Effect of Curcuma longa and Ocimum sanctum on myocardial apoptosis in experimentally induced myocardial ischemic-reperfusion injury. BMC Complement Altern Med . 2006;6:3.
38. Ahmed M, Ahamed RN, Aladakatti RH, Ghosesawar MG. Reversible anti-fertility effect of benzene extract of Ocimum sanctum leaves on sperm parameters and fructose content in rats. J Basic Clin Physiol Pharmacol . 2002;13(1):51-59.

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