Grapefruit-mediated fruit–drug interaction has been well discussed in clinical practice. However, the biochemical mechanisms for such interaction are far beyond our understanding. The objectives of the present study aimed at the interaction between bergaptol (BGT) and CYP2C9. BGT, one of the major furanocoumarin constituents in grapefruit, has been reported to inhibit the activity of CYP2C9. And a number of furan-containing compounds are known to act as mechanism-based inactivators of CYP2C9. In this study, BGT was found to induce time-, concentration-, and NADPH-dependent irreversible inhibition of CYP2C9. A GSH conjugate was detected in an incubation mixture containing CYP2C9, BGT, NADPH, and GSH. Further mechanistic investigation revealed that a γ-ketoenal metabolite was responsible for the enzyme inactivation. The obtained data indicate that BGT was a mechanism-based inactivator of CYP2C9. The study would facilitate the understanding of the mechanistic insight into fruit–drug interactions mediated by grapefruits.
Plant-parasitic nematodes cause substantial crop losses annually; however, current nematicides are environmentally unfriendly and highly toxic to nontarget organisms. The development of green efficient nematicides from multifunctional natural bioactive substances such as chitin oligosaccharide (COS) is promising. In this paper, COS dithiocarbamate derivatives (COSDTC, COSDTA, COSDTB) were synthesized to increase nematicidal activity (against Meloidogyne incognita ), and their structures were characterized by FTIR, NMR, TGA/DTG and elemental analysis. Furthermore, the nematicidal activities, egg hatching inhibitory activities, plant growth adjustment abilities, cytotoxicity and phytotoxicity of the derivatives were evaluated. The primary mechanism was assessed by heavy metal ion absorption and GSH-binding assays. The results showed COS dithiocarbamate derivatives could possess multiple efficacies, including high nematicidal activities and egg hatching inhibitory activities, plant growth regulating effects, low cell toxicities and phytotoxicities. Additionally, it was inferred that nematicidal activity may be correlated with GSH-binding activity but not heavy metal ion complexation. COS modification has immense potential for controlling plant-parasitic nematodes.