Cytochrome P450 inhibition potential and initial genotoxic evaluation of 14-O-[(4,6-diaminopyrimidine-2-yl)thioacetyl] mutilin

Yunxing Fu,Yuan Fan,Ruofeng Shang,Yunpeng Yi

doi:10.1038/s41598-020-70400-8

Abstract

14-O-[(4,6-Diaminopyrimidine-2-yl)thioacetyl] mutilin (DPTM) is a promising drug candidate with excellent antibacterial activity against Gram-positive bacteria. The present study was designed to characterize its Cytochrome P450 (CYP) enzymes inhibition activities and the genotoxicity with the standard Ames test. We determined the inhibitory effects of DPTM on CYP1A2, CYP2D1/6, CYP2E1, CYP2C11/9 and CYP3A/4 in rat liver microsomes (RLMs) and in human liver microsomes (HLMs). The mRNA expressions of the above CYP isoforms and their transcriptional regulators were also evaluated using the Hep G2 cell model. The results showed DPTM exhibited a moderate inhibitory potential against CYP3A/4 (IC50 values of 10 ± 2 and 8 ± 2 μM, respectively) and weak against the other CYP enzymes based on their IC50 values. Compared to the control, CYP isoforms and their transcriptional regulators mRNA expressions significantly increased when the Hep G2 cells were treated with DPTM for a certain period of time. In the Ames test, Salmonella strains TA97, TA98, TA100, TA102 and TA1535 were treated with or without the metabolic activation (S9). Analysis showed the average number of revertant colonies per plate was less in double in the groups treated with DPTM than that in the negative control plate and showed no dose-related increase.

Highlights

Pleuromutilin (Fig. 1), a 5-6-8 tricycle diterpene, was first discovered and isolated from two basidiomycete species in 1 9511
As previous studies reported that pleuromutilin analogues showed high Cytochrome P450 (CYP) inhibition effect[17,18], we evaluated the inhibitory effects of DPTM on the major CYP enzymes, including CYP1A2, CYP2D1, CYP2E1, CYP2C11 and CYP3A in rat liver microsomes (RLMs) and CYP1A2, CYP2D6, CYP2E1, CYP2C9 and CYP3A4 in human liver microsomes (HLMs)
The results showed revertant colonies were observed in all positive groups and were much more in double than that induced by five concentrations of DPTM and dimethyl sulfoxide (DMSO) (Table 2)

Summary

Introduction

Pleuromutilin (Fig. 1), a 5-6-8 tricycle diterpene, was first discovered and isolated from two basidiomycete species in 1 9511. A novel pleuromutilin derivative, 14-O-[(4,6-Diaminopyrimidine-2-yl)thioacetyl] mutilin (DPTM, Fig. 1), was synthesized and reported in ours previous work[16]. This compound showed the excellent in vitro activities against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), as well as in vivo activity using systemic infection mode in mice[16]. As previous studies reported that pleuromutilin analogues showed high CYP inhibition effect[17,18], we evaluated the inhibitory effects of DPTM on the major CYP enzymes, including CYP1A2, CYP2D1, CYP2E1, CYP2C11 and CYP3A in rat liver microsomes (RLMs) and CYP1A2, CYP2D6, CYP2E1, CYP2C9 and CYP3A4 in human liver microsomes (HLMs). The genotoxic properties of DPTM were assessed by the standard Ames test with and without metabolic activation (S9)

Methods

Results

Conclusion