Host–Guest Formulation of Carboxylatopillar[6]arene with Ergothioneine as a New Antidote for Combinational Detoxification of Paraquat

Paraquat (PQ) is exceptionally toxic to the human body. PQ ingestion can cause severe organ damage with a mortality rate of 50–80%, resulting from the absence of effective antidotes and detoxification solutions. Herein, a host–guest formulation is proposed, in which ergothioneine (EGT), an antioxidant drug, was encapsulated by carboxylatopillar[6]arene (CP6A) to achieve a combinational therapy for PQ poisoning. Nuclear magnetic resonance (NMR) and fluorescence titration were employed to confirm the complexation between CP6A and EGT as well as PQ with robust affinities. In vitro studies proved that EGT/CP6A significantly reduced PQ toxicity. Treatment with EGT/CP6A could effectively relieve organ damage caused by PQ ingestion and enhance the normalization of hematological and biochemical parameters. The host–guest formulation EGT/CP6A also improved the survival ratio in PQ-poisoned mice. These favorable outcomes originated from synergistic effects that PQ triggered the release of EGT to combat peroxidation damage and excess PQ was engulfed within the cavity of CP6A.