Basil
StarOcimum basilicum
Synonyms: Ocimum odorum
Western Herbalism Properties
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Botanical Description
Ocimum basilicum, common or sweet basil, is a tender annual herb in the Lamiaceae family native to tropical Asia and Africa and cultivated worldwide for culinary and medicinal use. The plant grows thirty to seventy centimetres tall with erect, square, often pinkish stems that are branched and slightly hairy. The opposite leaves are bright green, ovate to elliptic, three to seven centimetres long, with slightly toothed or entire margins and a glossy, sometimes slightly puckered surface. Crushed leaves release a strong, sweet, clove-like aroma due to volatile oils rich in linalool, eugenol, and methyl chavicol. Small two-lipped white or pale lilac flowers are borne in whorled terminal racemes; each whorl bears six flowers subtended by leafy bracts. After flowering, four small smooth nutlets develop within the persistent calyx. Many cultivated forms differ in leaf colour, shape, and aroma.
Active Constituents
Linalool
Acyclic monoterpene alcoholConcentration: Often the dominant essential-oil component in European/linalool chemotypes (~29-70%).
Chief contributor to the sweet, floral aroma; associated with anxiolytic, anti-inflammatory, antimicrobial and mild sedative effects.
Estragole (methylchavicol)
PhenylpropeneConcentration: Dominant in estragole-chemotype oils (up to ~45%); much lower in linalool chemotypes.
Responsible for the anise-like note and much of the anti-inflammatory/antiedematogenic activity in animal models, but is a recognised genotoxic/carcinogenic compound at high exposures (bioactivated to a 1'-sulfoxy metabolite); a driver of regulatory limits on basil essential oil.
Eugenol
Phenylpropene (phenolic)Concentration: Variable major/minor constituent depending on chemotype.
Antioxidant, analgesic and antimicrobial phenylpropanoid; contributes clove-like aroma and inhibits inflammatory mediators.
Methyl cinnamate
Phenylpropanoid esterConcentration: Major component of certain (e.g. some tropical) chemotypes.
Contributes a sweet, balsamic aroma and shows antimicrobial and insect-repellent activity.
1,8-Cineole (eucalyptol)
Oxygenated monoterpeneConcentration: Common minor-to-moderate oil constituent.
Associated with anti-inflammatory, expectorant and antimicrobial actions.
β-Caryophyllene (and α-bergamotene, germacrene D)
Sesquiterpene(s)Concentration: Minor volatile constituents.
β-Caryophyllene is a dietary CB2-receptor agonist with anti-inflammatory activity; contributes woody/spicy notes.
Rosmarinic acid
Hydroxycinnamic acid (caffeic acid ester)Concentration: Principal water-soluble phenolic of leaf extracts.
Potent antioxidant and anti-inflammatory polyphenol; a major contributor to the activity of aqueous/hydroalcoholic basil extracts as opposed to the essential oil.
⚠ Drug Interactions
Warfarin and other anticoagulant/antiplatelet drugs
In vitro, aqueous basil extracts significantly and concentration-dependently prolong prothrombin time and appear to act synergistically with warfarin, attributed to phenolic constituents; no controlled human data yet confirm the effect.
Clinical note: Use culinary amounts freely, but monitor INR and watch for bleeding if concentrated basil extracts/supplements are combined with anticoagulants.
CYP3A4 / CYP2B6 substrate drugs (e.g. rifampicin and other P450-metabolised medicines)
In vitro assessment shows Ocimum basilicum extracts can modulate CYP2B6 and CYP3A4 activity and rifampicin metabolism, suggesting a theoretical potential to change the clearance of drugs handled by these enzymes.
Clinical note: Clinically relevant only with high-dose concentrated extracts; unlikely from dietary use. Consider when patients take narrow-therapeutic-index CYP3A4 substrates alongside basil supplements.
Antidiabetic (hypoglycaemic) agents
Randomised trials and reviews report that Ocimum basilicum can lower fasting/postprandial glucose and improve insulin sensitivity, which could add to the effect of glucose-lowering drugs.
Clinical note: Monitor blood glucose when concentrated basil products are added to established antidiabetic therapy.
Preparation Methods
Culinary use and infusion of fresh/dried leaves
Parts: leaves, flowering tops
Fresh leaves are eaten raw or added to food; dried leaves can be infused as a mild carminative and calming tea. Dietary and infusion amounts are considered safe.
Essential oil (steam-distilled aerial parts)
Parts: leaves, flowering tops
Used topically (well diluted) and in aromatherapy. Because estragole-rich chemotypes are genotoxic/carcinogenic at high exposures, the essential oil should not be taken internally in appreciable quantities, should be kept within regulatory estragole limits, and is best avoided in pregnancy, in infants and for prolonged internal use.
Hydroalcoholic/aqueous leaf extract or syrup
Parts: leaves
Standardised extracts (rich in rosmarinic acid) are used in supplements and in the anxiety/glycaemic studies above; monitor with anticoagulant or antidiabetic therapy.
Clinical Studies
Basil (Ocimum basilicum) to Alleviate Anxiety in Patients With Major Depressive Disorder: A Randomized Placebo-Controlled Clinical Trial
Basil syrup extract added to standard antidepressant therapy for four weeks produced significantly greater reductions in anxiety and depression (Beck) scores than placebo in patients with major depressive disorder.
Anti-inflammatory and antiedematogenic activity of the Ocimum basilicum essential oil and its main compound estragole: In vivo mouse models
Basil essential oil (from 50 mg/kg) and its main compound estragole (from 30 mg/kg) reduced histamine- and arachidonic-acid-induced paw oedema, decreased vascular permeability and inhibited leukocyte migration, demonstrating systemic anti-inflammatory activity.
Historical Texts
Ayurveda and classical Indian medicine (as one of the tulsi-related Ocimum species)
Ancient – classicalEuropean herbals (e.g. Culpeper's The English Physician / Complete Herbal)
17th centuryReferences
- Purushothaman B, Srinivasan RP, Suganthi P, Ranganathan B, et al.. A Comprehensive Review on Ocimum basilicum . Journal of Natural Remedies (2018) [DOI]
- Ch MA, et al. (review). Sweet Basil (Ocimum basilicum L.) — A Review of Its Botany, Phytochemistry, Pharmacological Activities, and Biotechnological Development . Plants (MDPI) (2023) [DOI]
- van den Berg SJPL, Restani P, Boersma MG, Delmulle L, Rietjens IMCM. Matrix-derived combination effect and risk assessment for estragole from basil-containing plant food supplements . Journal of AOAC International (2011) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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