Characterization of Casearin X Metabolism by Rat and Human Liver Microsomes

Author(s)

da Silva, Rodrigo Moreira ^{[1, 2]} ; de Gaitani, Cristiane Masetto ^[1] ; Mauriz Marques, Lucas Maciel ^[2] ; Baraco, Karina Fraige ^[3] ; Cavalheiro, Alberto Jose ^[3] ; Beraldo de Moraes, Luiz Alberto ^[4] ; Lopes, Norberto Peporine ^[2] ; Moraes de Oliveira, Anderson Rodrigo ^[4]

Affiliation

^[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Fis & Quim, NPPNS, Ribeirao Preto, SP - Brazil

^[3] Univ Estado Sao Paulo, Inst Quim, Dept Quim Organ, Nucleo Bioensaios Biossintese & Ecofisiol Prod Na, Araraquara, SP - Brazil

^[4] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ave Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Planta Medica; v. 85, n. 4, p. 282-291, MAR 2019.
• Web of Science Citations: 1

Abstract

Casearin X (CAS X) is the major clerodane diterpene isolated from the leaves of Casearia sylvestris and has been extensively studied due to its powerful cytotoxic activity at low concentrations. Promising results for in vivo antitumor action have also been described when CAS X was administered intraperitoneally in mice. Conversely, loss of activity was observed when orally administered. Since the advancement of natural products as drug candidates requires satisfactory bioavailability for their pharmacological effect, this work aimed to characterize the CAS X metabolism by employing an in vitro microsomal model for the prediction of preclinical pharmacokinetic data. Rat and human liver microsomes were used to assess species differences. A high-performance liquid chromatography with diode-array detection (HPLC-DAD) method for the quantification of CAS X in microsomes was developed and validated according to European Medicines Agency guidelines. CAS X was demonstrated to be a substrate for carboxylesterases via hydrolysis reaction, with a Michaelis-Menten kinetic profile. The enzyme kinetic parameters were determined, and the intrinsic clearance was 1.7-fold higher in humans than in rats. The hepatic clearance was estimated by in vitro - in vivo extrapolation, resulting in more than 90% of the hepatic blood flow for both species. A qualitative study was also carried out for the metabolite identification by mass spectrometry and indicated the formation of the inactive metabolite CAS X dialdehyde. These findings demonstrate that CAS X is susceptible to first-pass metabolism and is a substrate for specific carboxylesterases expressed in liver, which may contribute to a reduction in antitumor activity when administered by the oral route. (AU)

• FAPESP's process: 16/06366-5 - Natural and synthetic xenobiotics bioavailability on in vitro models
• Grantee: Rodrigo Moreira da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/07597-0 - Development of chromatographic/electrophoretic methods to be further used in in vitro enzymatic inhibition and drug interaction of chiral pesticides
• Grantee: Anderson Rodrigo Moraes de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/03446-7 - In vitro metabolism studies of the antitumor Clerodane diterpene casearin X
• Grantee: Rodrigo Moreira da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate