In vitro modulatory effects of Andrographis paniculata; Centella asiatica and Ortho siphon stamineus on cytochrome P450 2C19 (CYP2C19)

J Ethnopharmacol. 2010 Nov 17. [Epub ahead of print]

In vitro modulatory effects of Andrographis paniculata; Centella asiatica and Ortho siphon stamineus on cytochrome P450 2C19 (CYP2C19).

Pan Y, Abd-Rashid BA, Ismail Z, Ismail R, Mak JW, Pook PC, Er HM, Ong CE.

School of Pharmacy and Health Sciences, International Medical University, 126, Jalan 19/155B, Bukit Jalil, 57000 Kuala Lumpur, Malaysia.

Abstract

ETHNO PHARMACOLOGICAL

RELEVANCE: Andrographils paniculata (AP), Centella asiatica (CA) and Orthosiphon stamineus (OS) are three popular herbs tradtionally used worldwide. AP is known for the treatment of infections and diabetes and CA is good for wound healing and heathy skin while OS is usually consumed as tea to treat kidney and urinary disorders. Interaction of these herbs with human cytochrome P450 2C19 (CYP2C19), a major hepatic CYP isoform involved in metabolism of many clinical drugs have not been investigated to date.

AIM OF THE STUDY: In this study, the modulatory effects of various extracts and major active constituents of AP, CA and OS on CYP2C19 acitvities were evaluated.

MATERIALS AND METHODS: S-mephenytoin, the CYP2C19 substrate probe, was incubated in the presence or absence of AP, CA and OS components. The changes in the rate of metabolite (hydroxymephenytoin) formation was subsequently determined by a high-performance liquid chromatography (HPLC)-based enzyme assay to characterize the modulatory effects.

RESULTS: Among the herbal extacts studied, AP ethanol extract and CA dichloromethane extract exhibited mixed type inhibition towards CYP2C19 with K(i) values of 67.1 and 16.4μg/ml respectively; CA ethanol extract and OS petroleum ether extract competitively inhibited CYP2C19 activity (K(i)=39.6 and 41.5μg/ml respectively). Eupatorin (a major active constituent of OS) was found to significantly inhibit CYP2C19 by mixed type inhibition (K(i)=7.1μg/ml or 20.6μM).

CONCLUSIONS: It was observed that AP, CA and OS inhibited CYP2C19 activity with varying potency. While weak inhibitory effect was observed with AP, moderate to strong inhibition was observed with CA dichloromethane extract and eupatorin, the major OS constituent. Therefore care should be taken when these CA and OS components are co-administered with CYP2C19 substrates (such as omeprazole, proguanil, barbiturates, citalopram, and diazepam).

Copyright © 2010. Published by Elsevier Ireland Ltd.
PMID: 21093571 [PubMed - as supplied by publisher]