Ceylon Clove Basil (Ocimum gratissimum)

Ceylon clove basil (Ocimum gratissimum) is a tropical herb whose primary bioactive compound, eugenol, inhibits bacterial cell membranes and suppresses pro-inflammatory mediators including COX-2 and NF-κB. Its essential oil demonstrates broad-spectrum antimicrobial and analgesic activity supported by preliminary in vitro and animal research.

Origin & History

Ceylon Clove Basil (Ocimum gratissimum) is a perennial herbaceous plant in the Lamiaceae family native to Africa and widely distributed in tropical regions including Asia and South America. The leaves are primarily used for extraction of essential oils via steam distillation or ethanol extracts through solvent methods, yielding aromatic essential oils rich in monoterpenes and phenylpropanoids.

Historical & Cultural Context

In traditional medicine systems across Africa and Asia, Ocimum gratissimum treats diabetes, cancer, inflammation, anaemia, diarrhoea, pains, fungal infections, and bacterial ailments. It has been historically used as both a spice and herbal remedy for microbial infections, particularly those caused by E. coli and S. aureus.

Health Benefits

• Antimicrobial activity against bacteria including S. aureus and E. coli (preliminary evidence from in vitro studies, MICs 12.5-50 mg/ml)
• Pain relief demonstrated in animal models at 20-40 mg/kg oral dosing (preliminary evidence, PMID: 26584457)
• Anti-inflammatory effects suggested by traditional use and preclinical studies (evidence quality: traditional/preliminary)
• Potential antifungal properties with synergistic effects when combined with ketoconazole against C. albicans (preliminary in vitro evidence)
• Membrane-disrupting antimicrobial mechanism showing rapid killing within 5 seconds at 4x MIC (preliminary in vitro evidence)

How It Works

The dominant volatile compound eugenol (often comprising 60-80% of the essential oil) disrupts bacterial cell membrane integrity by intercalating into lipid bilayers, reducing membrane fluidity and causing leakage of intracellular contents, which explains minimum inhibitory concentrations of 12.5-50 mg/ml against pathogens like S. aureus and E. coli. Eugenol also inhibits cyclooxygenase-2 (COX-2) enzyme activity and suppresses NF-κB transcription factor signaling, reducing downstream synthesis of prostaglandin E2 and pro-inflammatory cytokines such as TNF-α and IL-6. Secondary phenylpropanoids including thymol and methyl eugenol may contribute additive antimicrobial effects through similar membrane-disruption mechanisms.

Scientific Research

No human clinical trials, RCTs, or meta-analyses were identified for Ocimum gratissimum; all evidence is limited to preclinical in vitro and animal studies. One animal study (PMID: 26584457) in C57BL/6J mice showed antihypernociceptive effects at 20-40 mg/kg oral dosing, while in vitro studies demonstrated antimicrobial activity with MICs of 12.5-50 mg/ml against various bacteria.

Clinical Summary

Available evidence for Ceylon clove basil is limited to in vitro antimicrobial studies and rodent models, with no completed randomized controlled human trials published as of 2024. Antimicrobial activity has been demonstrated in disc-diffusion and broth microdilution assays against S. aureus, E. coli, and Candida species, with MICs ranging from 12.5 to 50 mg/ml for crude extracts. Analgesic effects were observed in murine models using oral doses of 20-40 mg/kg, showing statistically significant reductions in acetic acid-induced writhing comparable to reference analgesics in some studies (PMID: 26584457). The overall evidence base is preliminary, and efficacy and optimal dosing in humans remain unestablished.

Nutritional Profile

Ocimum gratissimum leaves contain moderate moisture (70-80% fresh weight basis). Macronutrient composition per 100g dry weight: crude protein 10-15g, crude fiber 12-18g, crude fat 4-7g, ash 8-12g, carbohydrates approximately 50-60g. Key micronutrients include calcium (1,200-2,100mg/100g dry weight), potassium (800-1,500mg/100g), magnesium (200-400mg/100g), iron (28-50mg/100g), zinc (4-8mg/100g), and phosphorus (150-300mg/100g); mineral bioavailability is moderately reduced by presence of oxalates and tannins. Vitamin content includes ascorbic acid (vitamin C) at 50-150mg/100g fresh weight, beta-carotene (provitamin A precursor) at 2-5mg/100g, and small amounts of B vitamins including riboflavin and niacin. The dominant bioactive compounds are volatile essential oils comprising 0.5-3.5% of leaf dry weight, with thymol (up to 40-60% of essential oil fraction in some chemotypes), eugenol (15-30% in eugenol-dominant chemotypes), and geraniol as primary constituents; chemotype variation is significant and affects bioactive profile substantially. Non-volatile phenolics include rosmarinic acid (reported at 2-8mg/g dry weight), luteolin, apigenin, and orientin glycosides. Ursolic acid and oleanolic acid triterpenes are present at approximately 1-3mg/g dry weight. Bioavailability of phenolics is estimated at 10-30% based on related Ocimum species data; essential oil constituents such as eugenol and thymol demonstrate good oral absorption in animal models. Data on human bioavailability is limited and extrapolated primarily from related species.

Preparation & Dosage

No clinically studied human dosages available. Animal studies used essential oil at 10-40 mg/kg orally (effective at 20-40 mg/kg for pain relief). In vitro antimicrobial studies report MICs of 12.5-50 mg/ml for crude extracts and 1.56-12.5% (w/v) for ethanol extracts. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Eugenol, Myrcene, Ketoconazole (for antifungal), Ampicillin (for antibacterial), Traditional African herbs

Safety & Interactions

High-dose or undiluted essential oil containing concentrated eugenol may cause oral mucosa irritation, contact dermatitis, and hepatotoxicity, as eugenol is metabolized hepatically via glucuronidation and sulfation pathways. Because eugenol inhibits platelet aggregation by suppressing thromboxane A2 synthesis, concurrent use with anticoagulants such as warfarin or antiplatelet drugs like aspirin and clopidogrel may increase bleeding risk. Eugenol-rich preparations may also inhibit CYP1A2 and CYP3A4 enzymes, potentially elevating plasma concentrations of drugs metabolized by these pathways. Safety during pregnancy and lactation has not been formally evaluated; traditional use suggests caution, and high-dose supplemental forms should be avoided during pregnancy.