In-vitro and in-vivo evaluations of cytochrome P450 1A2 interactions with nuciferine

OBJECTIVES: The effects of nuciferine, a major active aporphine alkaloid from the leaves of Nelumbo nucifera Gaertn, on a cytochrome P450 1A2 (CYP1A2) probe substrate were investigated in vitro and in vivo. METHODS: Nuciferine and recombinant human CYP1A2 were incubated together to study the impact of nuciferine on CYP1A2 in vitro. Nuciferine was administered orally to Wistar rats at a dose of 20 mg/kg to further estimate the impact of nuciferine on CYP1A2 in vivo. A probe substrate, phenacetin, was used to index the activity of CYP1A2. KEY FINDINGS: The IC50 value for nuciferine was determined to be 2.12 mmol/l. When phenacetin was intravenously coadministered with nuciferine compared with phenacetin alone, the elimination rate constant and total body clearance of phenacetin were decreased by 24.0% (P < 0.01) and 43.0% (P < 0.05), respectively. The mean residence time, apparent elimination half-time and area under the plasma concentration-time curve were increased by 22% (P < 0.005), 26.9% (P < 0.02) and 74.6% (P < 0.05), respectively. Similarly, when phenacetin was coadministered orally with nuciferine, the apparent elimination half-time in the nuciferine pretreated group was increased by 16.7% (P < 0.05) and the elimination rate constant was decreased by 15.4% (P < 0.05). CONCLUSIONS: The results suggest that nuciferine inhibited CYP1A2 activity in vitro and caused changes in the pharmacokinetic parameters of phenacetin in vivo.