Glutathione S-Transferases Mediate In Vitro and In Vivo Inactivation of Genipin: Implications for an Underlying Detoxification Mechanism

Abstract

Genipin (GP), the reactive metabolite of geniposide (GE), is responsible for GE-induced hepatotoxicity. As a potential detoxification pathway, the inactivation of GP by glutathione S-transferases (GSTs) has not yet been characterized. In this study, the thiol-GSH conjugates of GP, M532-1 and M532-2 were first identified and the catalytic activities of GSTs were investigated both in vitro and in vivo. GSTA1-1 and GSTA4-4 showed high activity in the formation of both thiol-GSH conjugates, whereas GSTA4-4 specifically catalyzed M532-2 formation in vitro. The active GST isoforms protect against alkylation of Nacetylcysteine (NAC), a classic model nucleophile. GST inhibition attenuated M532-1 formation in rat bile, confirming the in vivo catalytic role of GSTs. In conclusion, this study demonstrated the inactivation of GP by GSTs and implied that interindividual variability of GSTs may be a risk factor for susceptibility to GE-induced hepatotoxicity.

Unraveling a Combined Inactivation Mechanism of Cytochrome P450s by Genipin, the Major Reactive Aglycone Derived from Gardeniae Fructus

“…Notably, the previously reported GP-N-GSH conjugate, M496, 5 was also detected in our in vitro studies 34 (Figure S1). As previously reported, M496 formation resulted from the direct conjugation of the primary amino group of GSH to GP, representing the nonenzymatic amino reactivity of GP.…”

“…Although the absolute concentrations of M496 and M530 in vitro and in vivo can only be compared via quantification using synthetic standards, rough comparison based on peak height make it clear that M530 formation is more prevalent in vivo and M496 is more abundant in vitro. M496 is likely produced via the ring opening of GP from a dialdehyde intermediate and subsequent conjugation to the amino residue of GSH . A previous in vivo study found high levels of GP–amino acid conjugates that likely compete with M496 formation .…”

“…M496 is likely produced via the ring opening of GP from a dialdehyde intermediate and subsequent conjugation to the amino residue of GSH. 34 A previous in vivo study found high levels of GP−amino acid conjugates that likely compete with M496 formation. 5 Therefore, the low level of M496 and high level of M530 in vivo shown in this study revealed the major binding mode of GP to thiol residues in biomolecules under physiological conditions.…”

Thermal-Driven Curcumin Release Film with Dual-Mode Synergistic Antibacterial Behavior for Efficient Tangerine Preservation

“…Meanwhile, the long-lasting antibacterial ability can be achieved by the thermal-controlled release of curcumin. 24,52,53 As shown in Figure 4d, all the films doped with curcumin showed a sustained release phenomenon. The final release curcumin concentrations order of those films was CS/Cur > CCF 0.05 > CCF 0.1 > CCF 0.15 > CCF 0.2 , and the release rate constant (k) of Cur-based films decreased with the increase of doped Fe-MoO x (SI, Figure S13 and Table S1), which indicated that the doping Fe-MoO x could prolong the release time of curcumin, achieving long-lasting antibacterial effect.…”

GSTP alleviates acute lung injury by S-glutathionylation of KEAP1 and subsequent activation of NRF2 pathway

“…All other chemicals were offered by Sigma-Aldrich, if not otherwise indicated. Recombinant human GSTP was prepared in our laboratory as described previously [ 29 ].…”