Synthesis of Spin-Labelled Bergamottin: A Potent CYP3A4 Inhibitor with Antiproliferative Activity

Abstract

Bergamottin (BM, 1), a component of grapefruit juice, acts as an inhibitor of some isoforms of the cytochrome P450 (CYP) enzyme, particularly CYP3A4. Herein, a new bergamottin containing a nitroxide moiety (SL-bergamottin, SL-BM, 10) was synthesized; chemically characterized, evaluated as a potential inhibitor of the CYP2C19, CYP3A4, and CYP2C9 enzymes; and compared to BM and known inhibitors such as ketoconazole (KET) (3A4), warfarin (WAR) (2C9), and ticlopidine (TIC) (2C19). The antitumor activity of the new SL-bergamottin was also investigated. Among the compounds studied, BM showed the strongest inhibition of the CYP2C9 and 2C19 enzymes. SL-BM is a more potent inhibitor of CYP3A4 than the parent compound; this finding was also supported by docking studies, suggesting that the binding positions of BM and SL-BM to the active site of CYP3A4 are very similar, but that SL-BM had a better ∆Gbind value than that of BM. The nitroxide moiety markedly increased the antitumor activity of BM toward HeLa cells and marginally increased its toxicity toward a normal cell line. In conclusion, modification of the geranyl sidechain of BM can result in new CYP3A4 enzyme inhibitors with strong antitumor effects.

Testing the Pharmacokinetic Interactions of 24 Colonic Flavonoid Metabolites with Human Serum Albumin and Cytochrome P450 Enzymes

“…Thus, our results are consistent with the previously reported data. Despite the fact that RES and PHLO are much weaker inhibitors of CYP3A4 than ketoconazole, they caused similarly strong inhibition of the enzyme in the same experimental model as bergamottin did [42] (which shows clinically relevant interaction with CYP3A4). Therefore, the effects of RES and PHLO on CYP3A4 may cause relevant pharmacokinetic interactions, while the inhibitory effect of 24DHAP and DESMA does not seem considerable.…”

“…Atomic partial charges of heme were adopted as the ferric penta coordinate high spin charge model from reference [41]. The rest of the target molecule was equipped with polar hydrogen atoms and Gasteiger-Marsilli partial charges in AutoDock Tools as in our previous study [42].…”

“…The latter found a position appearing to be a final binding mode, due to its unambiguous coordination to the heme iron ( Figure 9). Likewise ketoconazole (a well-known inhibitor of CYP3A4), where the imidazole N atom of ketoconazole coordinates to the heme iron with a distance of 2.70 Å [42], this binding mode of the R-DESMA was reached in the top 3 rd rank with the O atom of its hydroxyl group being of 3.60 Å distance from the heme iron (regarding CYP2C9). G296, T301, T304 and S478 amino acids of the enzyme form H-bonds with the ligand.…”

The Grapefruit Effect: Interaction between Cytochrome P450 and Coumarin Food Components, Bergamottin, Fraxidin and Osthole. X-ray Crystal Structure and DFT Studies

“…The DHB psoralen ring lies above the heme and parallel to the I-helix, with the carbonyl oxygen H-bonded to the S119 hydroxyl group. Very recently, docking calculations on bergamottin, and a synthesized bergamottin derivative containing a nitroxide moiety and having antitumor effects, with CYP3A4 (PDB 2V0M), were performed [8].…”

“…The difference in energy between poses 5 and 6 was marked, 6.2 kcal/mol favoring pose 6, and so, the π-π configuration is energetically more stable. It is interesting to compare our pose 6 configuration with a docking study of bergamottin [8], which used a different receptor (PDB 2V0M) derived from the crystal structure of CYP3Y4 together with inhibitor ketoconazole. After docking, a stacking configuration was also concluded.…”