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As compounds of natural origin enter human body, it is necessary to investigate their possible interactions with the metabolism of drugs and xenobiotics in general, namely with the cytochrome P450 (CYP) system. Phytic acid (myo-inositol hexaphosphoric acid, IP6) is mainly present in plants but is also an endogenous compound present in mammalian cells and tissues. It has been shown to exhibit protective effect in many pathological conditions. For this paper, its interaction with CYPs was studied using human liver microsomes, primary human hepatocytes, the HepG2 cell line, and molecular docking. Docking experiments and absorption spectra demonstrated the weak ability of IP6 to interact in the heme active site of CYP1A. Molecular docking suggested that IP6 preferentially binds to the protein surface, whereas binding to the active site of CYP1A2 was found to be less probable. Subsequently, we investigated the ability of IP6 to modulate the metabolism of xenobiotics for both the mRNA expression and enzymatic activity of CYP1A enzymes. Our findings revealed that IP6 can slightly modulate the mRNA levels and enzyme activity of CYP1A. However, thanks to the relatively weak interactions of IP6 with CYPs, the chances of the mechanisms of clinically important drug–drug interactions involving IP6 are low. [ABSTRACT FROM AUTHOR]

Aim: Cytochrome P450 is a hepatic enzyme system responsible for drug metabolism that comprises different iso-enzymes. The CYP2D6 enzyme, which composes 2-4% of all cytochrome enzymes, is responsible for 25% of the metabolisms of the drugs used in clinics. The genetic polymorphisms of this enzyme can change the efficiency and toxicity of the drugs used. In this study, the retrospective evaluation of CYP2D6 gene polymorphisms that influence enzyme activity in the Turkish population is targeted. Materials and Methods: From the 192 patients sent from psychiatry, medical genetics, and neurology polyclinics to our laboratory, we determined CYP2D6 enzyme gene polymorphisms by multiplex polymerase chain reaction (PCR) and multiplex allele-specific primer extension (ASPE). Results: Of all the cases, 82.29% were determined to be extensive, 12.5% intermediate, 2.08% poor, and 3.13% ultra-rapid metabolizers. In our population, the most frequent alleles were *1 (37.63%), *2 (24.75%), *41 (15.15%), *4 (9.85%), and *10 (4.29%), respectively. Conclusion: Compared to previous studies conducted on Turkish society, the percentage of extensive metabolizers was higher in the current examined population. In contrast, the percentages of poor and ultra-rapid metabolizers were lower. In addition, the *41 allele, which has not been studied before in our population, that follows the decrease in enzyme function was detected as the most frequent allele in this study. The fact that the percentage of the cases in which changes were observed was 17.1% will help determine the CYP2D6 gene mutations in the pre-treatment cases. [ABSTRACT FROM AUTHOR]