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Licensed Unlicensed Requires Authentication Published by De Gruyter June 20, 2015

Polymorphisms of CYP1A2 and CYP2A6 activity: phenotypes and the effect of age and sex in a Nigerian population

  • Ayorinde Adehin ORCID logo EMAIL logo and Oluseye O. Bolaji


Background: CYP1A2 and CYP2A6 are polymorphic enzymes that metabolise several compounds of clinical importance. This study investigated the prevalent phenotypes of these enzymes and the influence of age and sex on enzyme activity in a Nigerian population.

Methods: Caffeine (110 mg) was administered to each of 129 healthy, unrelated subjects (85 males and 44 females) who were non-smokers. Urine voided within 7 h after caffeine administration was collected for a high performance liquid chromatographic assay of caffeine (137X), 1,7-dimethyluric acid (17U) and 1,7-dimethylxanthine (17X). CYP1A2 activity was measured as a ratio of (17U+17X) to 137X, while 17U/17X served as marker for CYP2A6. Transformed data were analysed and the influences of age and sex on activity were also determined.

Results: Distribution of CYP1A2 activity in the population was bimodal with a mean±SD of 0.82±0.41, while that of CYP2A6 was trimodal with a mean±SD activity of 0.27±0.42 of the log-transformed urinary molar ratio of metabolites. The influences of age and sex on enzyme activity for both CYP1A2 and CYP2A6 were not significant (p>0.05).

Conclusions: The study established the prevalence of polymorphism in phenotypes of CYP1A2 and CYP2A6 activity in the Nigerian population, but no influence of age and sex on enzyme activity was observed in this population.

Corresponding author: Ayorinde Adehin, Faculty of Pharmacy, Department of Pharmaceutical Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria, Phone: +2348022013470, E-mail: ;


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Received: 2015-1-26
Accepted: 2015-5-27
Published Online: 2015-6-20
Published in Print: 2015-9-1

©2015 by De Gruyter

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