CYP2C19 Variants and Limonene Metabolism

Not Applicable

Recruiting

• Conditions: CYP2C19 Genetic Variants
• Interventions: Dietary Supplement: Limonene

• Registration Number: NCT05078723
• Lead Sponsor: Stanford University

Brief Summary

The investigators will examine whether a non-invasive screening tool for CYP2C19 genetic variants can be developed by measuring limonene metabolism.

Detailed Description

Cytochrome P450 2C19 is an important enzyme that metabolizes many drugs. However, individuals with genetic variants of CYP2C19, such as CYP2C19\*2 and CYP2C19\*3, are poor metabolizers of these drugs. Therefore, it is of interest to determine whether the investigators can develop a non-invasive assay to identify genetic variants of CYP2C19 by using a substrate for CYP2C19 found in citrus fruit, limonene. The purpose of the study is to examine changes in limonene levels in human breath after drinking orange peel extract for people with CYP2C19\*2 and CYP2C19\*3 genetic variants versus those that do not.

Study Timeline

• Study First Submitted: 2021-07-01
• Study First Submitted QC: 2021-10-12
• Study First Posted: 2021-10-14
• Study Start: 2021-10-30
• Status Verified: 2024-12
• Last Update Submitted: 2024-12-10
• Last Update Posted: 2024-12-16
• Primary Completion: 2026-03
• Study Completion: 2026-12

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Age range: Greater than 18 years and less than 45 years.
• Gender: Male or Female
• Ethnicities: East Asian

Exclusion Criteria

• Pregnant and/or Breastfeeding
• previous allergic reaction to limonene, citrus fruits, bovine gelatin, glycerin
• past medical history of cerebrovascular or cardiovascular disease
• veganism
• history of chest pain or shortness of breath in the past month
• certain medications that are CYP2C19 substrates or CYP2C19 inhibitors
• Non-East Asian descent
• age less than 18 y.o or age greater than 45 y.o

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
CYP2C19*2 and CYP2C19*3 Variants	Limonene	The group of participants has been genotyped to have the CYP2C19\*2 and/or CYP2C19\*3 variant during the first part of the study. The participants will consume 1 oz water mixed with 500mg limonene (Jarrow Formula orange peel extract) and be asked to swish 5 times and swallow. All participants will then provide breath samples over the course of 2 hours. The breath sample outcomes will be compared to those of the wild-type CYP2C19 study subjects.
Wildtype CYP2C19	Limonene	The group of participants has been genotyped to have wild-type CYP2C19. The participants will consume 1 oz water mixed with 500mg limonene (Jarrow Formula orange peel extract) and be asked to swish 5 times and swallow. All participants will then provide breath samples over the course of 2 hours. The breath sample outcomes will be compared to those of the CYP2C19\*2 and/or CYP2C19\*3 study subjects.

Primary Outcome Measures

Name	Time	Method
Breath limonene value in parts per billion	2 hours	The amount of limonene in the breath will be measured by mass spectrometry for each participant.

Trial Locations

Locations (1)

Stanford School of Medicine; 🇺🇸 Stanford, California, United States