GSK3β/HIF-1α signaling-dependent anti-parasite effect of Cynanchi atrati Radix

Recently, many medicinal plants or their bioactive compounds have been evaluated in vitro and in vivo for their ability as novel drug candidates in the parasite control. 4’-Hydroxyacetophenone (4’HAP), a key compound in Cynanchi atrati Radix (C. atrati), has an anti-virus function and some anti-inflammatory effects. Nevertheless, the bioactivity of 4’’HAP remains to be identified in parasite prevention. Herein, we investigated whether 4’HAP has a pharmacological effect on the growth of Toxoplasma gondii (T. gondii) in ARPE-19 cells. We demonstrate that C. atrati exhibits significant suppression effect on T. gondii growth with minimal cytotoxicity in host cells. Screening of C. atrati constituents identified 4’HAP as an inhibitory compound capable of effectively restraining T. gondii proliferation. Mechanistic analyses revealed that both C. atrati and 4’HAP weaken T. gondii growth by destabilizing Hypoxia-Inducible Factor 1-alpha (HIF-1α), which is mediated via activation of Glycogen Synthase Kinase 3 beta (GSK3β). Pharmacological inhibition of GSK3β restored T. gondii proliferation, while depletion of HIF-1α further suppressed parasite survival, underscoring the importance of the GSK3β/HIF-1α axis in the observed anti-parasite effects. In all, we provide evidence that C. atrati and 4’HAP are promising anti-parasitic agents against T. gondii. Our findings provide a foundation for developing innovative strategies to combat T. gondii infection and address current gaps in treatment options.