Effects of the extracts and derived fractions of four medicinal plants on hepatic microsomal enzymes: an in-vitro study
Abidemi J. Akindele , Olufunmilayo O. Adeyemi and Margaret O. James
1Department of Pharmacology, Therapeutics & Toxicology (PTT), Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Idi-Araba Campus, P. M. B. 12003, Lagos, Nigeria
2Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610-0485, USA
Corresponding author: Abidemi J. Akindele
E-mail : jakindele@unilag.edu.ng Phone: +2348062359726
ABSTRACT
Background: The use of medicinal plants for treatment of diverse ailments has continued to increase worldwide, especially in developing countries. The concurrent use of herbal medicines and conventional drugs is common. Herb-drug interaction through the inhibition/induction of cytochrome (CYP) P450 metabolizing enzymes could result in pharmacotoxicity/therapeutic failure.
Objective: This study investigated the extracts and fractions of four medicinal plants (Crinum glaucum, Baphia nitida, Byrsocarpus coccineus, and Sanseviera liberica) for possible effects on hepatic microsomal enzymes in-vitro.
Methods: The benzyloxy-4-[trifluoromethyl]-coumarin O-debenzyloxylase (BFCOD; CYP3A4) and benzyloxyresorufin O-debenzylase (BROD; CYP2B1/2) assays were used.
Results: The ethyl acetate:methanol and ethanol:water extracts of the plants demonstrated significant (p < 0.05) inhibitory effect on CYP activity, pronouncedly at the highest concentration (1 mg/ml) in the BROD assay. The aqueous extracts and fractions of all the plants did not significantly affect CYP activity in both assays. The same trend of observation was recorded in the BFCOD assay except that the ethyl acetate:methanol extract of C. glaucum did not significantly affect CYP activity. The ethyl acetate:methanol extract of B. nitida and B. coccineus elicited significant stimulatory effect at 0.01 and 0.1 mg/ml in the BROD assay. The hexane and n-butanol fractions of the extracts showed varying tendency to cause stimulation of CYP activity at lower doses and inhibition at the highest dose.
Conclusion: Findings suggest that the aqueous extracts/fractions of the plants investigated have little or no tendency to significantly affect CYP activity. Other organic solvent extracts/fractions possess the ability to inhibit CYP activity, especially at high doses.
Keywords: Crinum glaucum, Baphia nitida, Byrsocarpus coccineus, Sanseviera liberica, Herb-drug interaction, Cytochrome P450 enzymes