Wise Mind Herbs

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Holy basil - Ocimum sp.

Tulsi, commonly known as Holy Basil, is a revered medicinal herb in Ayurvedic medicine with numerous reported health benefits. This review examines the scientific evidence for tulsi's therapeutic properties based on peer-reviewed literature.

Image source and license: https://commons.wikimedia.org/wiki/File:Ocimum_tenuiflorum_21.jpg.
Modified by Peter Jorgensen.

Botanical Classification and Common Names

Tulsi belongs to the genus Ocimum in the Lamiaceae family. The primary species with medicinal properties include:

• Ocimum sanctum L. (syn. Ocimum tenuiflorum) - Holy Basil, Sacred Basil, Shyama Tulsi (dark purple variety), Rama Tulsi (green variety)
• Ocimum gratissimum - Clove Basil, African Basil, Wild Basil, Vana Tulsi
• Ocimum basilicum - Sweet Basil, Thai Basil, Common Basil (often confused with medicinal tulsi but has different properties)
• Ocimum americanum - Hoary Basil, Lemon Basil (sometimes mistaken for medicinal tulsi)

Bioactive Compounds

The therapeutic effects of tulsi are attributed to various bioactive compounds, including eugenol, rosmarinic acid, carvacrol, ursolic acid, β-caryophyllene, linalool, 1,8-cineole, and various flavonoids and triterpenes. The concentration of these compounds varies by species, growing conditions, harvesting time, and extraction method.

Evidence-Based Health Benefits

• Adaptogenic properties: Multiple studies demonstrate tulsi's ability to help the body adapt to physical, chemical, and psychological stressors through modulation of the hypothalamic-pituitary-adrenal (HPA) axis.
• Anti-inflammatory effects: Inhibits pro-inflammatory enzymes (COX-2, LOX) and reduces inflammatory cytokines.
• Antioxidant activity: Scavenges free radicals and enhances endogenous antioxidant systems.
• Antimicrobial properties: Shows efficacy against various bacteria, fungi, and certain viruses in vitro.
• Immunomodulatory effects: Enhances cellular and humoral immune responses.
• Anticancer potential: Demonstrates antiproliferative, proapoptotic, and antiangiogenic activities in preclinical models.
• Cardioprotective effects: Reduces lipid levels, protects against ischemia-reperfusion injury, and shows antihypertensive properties.
• Neuroprotective activity: Protects against neurodegenerative diseases and shows anxiolytic and antidepressant-like effects.
• Anti-diabetic properties: Improves insulin sensitivity and reduces blood glucose levels.
• Hepatoprotective effects: Protects against chemical-induced liver damage.

Conditions with Moderate to Strong Evidence

• Stress and anxiety disorders
• Metabolic syndrome and type 2 diabetes
• Hyperlipidemia
• Mild to moderate hypertension
• Upper respiratory tract infections
• Cognitive decline associated with aging
• Non-alcoholic fatty liver disease

Conditions with Preliminary Evidence

• Depression
• Cancer (primarily as adjuvant therapy)
• Arthritis and inflammatory conditions
• Gastric ulcers
• Radiation-induced tissue damage
• Alzheimer's disease
• Allergic asthma
• Dental and oral infections

Recommended Dosages

Dosage recommendations vary based on preparation form and intended use:

• Dried leaf powder: 300-2000 mg daily, divided into 2-3 doses
• Leaf extract (2-5% ursolic acid): 300-600 mg daily
• Tincture (1:5 in 45% alcohol): 2-4 ml, three times daily
• Fresh leaves: 8-10 leaves (approximately 2-3 g) daily
• Tea: 1-2 g dried leaves steeped in 150 ml hot water for 5-10 minutes, 2-3 times daily
• Standardized extract (2% withanolides): 250-500 mg twice daily

Most clinical studies have used standardized extracts containing 2-5% ursolic acid and 1-3% eugenol. The optimal therapeutic window appears to be 600-1200 mg of standardized extract daily, with benefits plateauing at higher doses.

High-Dose Studies and Knowledge Gaps

Studies examining doses exceeding 2000 mg daily of dried herb equivalent or 1500 mg of standardized extract are limited. Animal toxicity studies suggest safety at much higher doses than typically used clinically, but human data on very high doses are lacking. No additional therapeutic benefits have been consistently documented at doses exceeding those mentioned above, suggesting a ceiling effect. Research gaps exist regarding long-term safety (>12 months), effects during pregnancy and lactation, and potential herb-drug interactions at high doses.

Side Effects and Safety Concerns

• Generally recognized as safe (GRAS) at recommended doses
• Mild gastrointestinal discomfort in some individuals (nausea, heartburn)
• May temporarily reduce fertility (animal studies indicate reversible anti-spermatogenic effects)
• Potential anticoagulant effects may enhance bleeding risk when combined with antiplatelet medications
• Theoretical interaction with thyroid medications due to effects on thyroid hormone levels
• May lower blood glucose, requiring monitoring in diabetic patients on medication
• Rare allergic reactions, particularly in individuals with basil allergy

Contraindications

• Pregnancy (due to insufficient safety data and potential uterine stimulant effects)
• Patients requiring surgery within two weeks (due to potential anticoagulant effects)
• Known hypersensitivity to plants in the Lamiaceae family

References

Cohen, M. M. (2014). Tulsi-Ocimum sanctum: A herb for all reasons. Journal of Ayurveda and integrative medicine, 5(4), 251.

Jamshidi, N., & Cohen, M. M. (2017). The clinical efficacy and safety of Tulsi in humans: a systematic review of the literature. Evidence‐Based Complementary and Alternative Medicine, 2017(1), 9217567.

Kumar, A. (2023). A systemic review of tulsi (Ocimum tenuiflorum or Ocimum sanctum): Phytoconstituents, ethnobotanical and pharmacological profile. Research Journal of Pharmacognosy and Phytochemistry, 15(2), 179-188.

Lopresti, A. L., Smith, S. J., Metse, A. P., & Drummond, P. D. (2022). 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. Frontiers in Nutrition, 9, 965130.

Mataram, M. B. A., Hening, P., Harjanti, F. N., Karnati, S., Wasityastuti, W., Nugrahaningsih, D. A. A., ... & Wihadmadyatami, H. (2021). The neuroprotective effect of ethanolic extract Ocimum sanctum Linn. in the regulation of neuronal density in hippocampus areas as a central autobiography memory on the rat model of Alzheimer’s disease. Journal of chemical neuroanatomy, 111, 101885.

Qasem, A., Assaggaf, H., Mrabti, H. N., Minshawi, F., Rajab, B. S., Attar, A. A., ... & Bouyahya, A. (2023). Determination of Chemical Composition and Investigation of Biological Activities of Ocimum basilicum L. Molecules, 28(2), 614.

Singh, D., & Chaudhuri, P. K. (2018). A review on phytochemical and pharmacological properties of Holy basil (Ocimum sanctum L.). Industrial Crops and Products, 118, 367-382.

Singh, N., Verma, P., Pandey, B.R. and Bhalla, M., 2012. Therapeutic potential of Ocimum sanctum in prevention and treatment of cancer and exposure to radiation: An overview. International Journal of pharmaceutical sciences and drug research, 4(2), pp.97-104.