NCT06693960

Evaluating the Pharmacokinetics of Oregano and Potential Oregano-drug Interactions Using a Drug Cocktail Approach

• Status: Recruiting
• Phase: EARLY_Phase 1
• Study type: Interventional
• Enrollment: 16 (estimated)
• Sponsor: Washington State University · Academic / Other
• Sex: All
• Age: 18 Years – 64 Years
• Healthy volunteers: Accepted

Summary

The purpose of this clinical trial is to determine how the supplement oregano affects how the body metabolizes pharmaceutical drugs.

Detailed description

Oregano (Origanum vulgare) is a flowering plant native to Europe. The fresh or dried leaves are commonly used as a cooking herb. Oregano oil extracts are also marketed as herbal supplements. O. vulgare ranked as the number 12 top-selling herbal supplement in the natural channel in 2022. Oregano supplements are consumed for myriad purported medicinal properties, including antimicrobial, antioxidant, and anti-inflammatory effects. Oregano contains multiple types of compounds, including phenols, terpenes, and terpenoids. Recent compelling in vitro data showed that an extract of O. vulgare activated the human pregnane X receptor (PXR) and aryl hydrocarbon receptor (AhR), which regulate the expression and activity of the prominent drug metabolizing enzymes cytochrome P450 (CYP) 3A4 and CYP1A2, respectively. PXR also regulates the expression and activity of several other CYPs (e.g., CYP2C9, CYP2C19), as well as transporters (e.g., the efflux transporter P-glycoprotein (P-gp)). The extent of activation of both receptors by O. vulgare rivaled that of St. John's wort, a well-known herbal supplement that induces CYP and P-gp activity in human participants. These investigators next evaluated the effects of O. vulgare on CYP3A4 and CYP1A2 activity in human hepatocytes. Again, the extent of induction by O. vulgare rivaled that of St. John's wort. Collectively, these observations suggest that oregano supplements could precipitate numerous interactions with pharmaceutical drugs. The primary objective of the proposed study is to evaluate the potential for a well-characterized O. vulgare product to precipitate pharmacokinetic interactions with a "cocktail" of oral drugs that are substrates for multiple CYPs. The investigators and others have shown this validated cocktail (caffeine, dextromethorphan, losartan, midazolam, and omeprazole) to be safe to administer to healthy adult participants. The secondary objective is to determine the pharmacokinetics of the oregano supplement, which to date have not been rigorously characterized in humans. Results will be used to help inform healthcare practitioners and consumers about the safe use of this increasingly popular herbal supplement when consumed with certain pharmaceutical drugs.

Conditions

• Interaction

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Oregano	Oil of oregano administered as a softgel (180 mg).
DRUG	Drug cocktail	Oral drug cocktail consisting of caffeine (100 mg), dextromethorphan (30 mg), losartan (25 mg), midazolam syrup (2 mg), and omeprazole (20 mg).

Timeline

• Start date: 2024-09-26
• Primary completion: 2025-09-15
• Completion: 2025-12-31
• First posted: 2024-11-19
• Last updated: 2024-11-26

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study