Spiropatuols A–H: Polycyclic Polyprenylated Acylphloroglucinols from Hypericum patulum with Activity against Concanavalin A–Induced Autoimmune Hepatitis

Eight new spiropolycyclic polyprenylated acylphloroglucinols, named spiropatuols A–H (1–8), were isolated from the traditional Chinese medicinal herb Hypericum patulum. The structures of compounds 1–8 were characterized using spectroscopic analysis, calculations of nuclear magnetic resonance chemical shifts with DP4+ probability analysis, and electronic circular dichroism calculations. Compounds 2–4 exhibited immunosuppressive activities in an in vitro model of concanavalin A (Con A)–induced murine splenocyte proliferation, with half-maximal inhibitory concentrations of 50, 70, and 200 nM, respectively. Furthermore, in a Con A–challenged autoimmune hepatitis mouse model, compound 2 inhibited Con A–induced activation of mice splenic lymphocytes and alleviated Con A–induced acute liver injury. These results indicate that the metabolites isolated in this study can inform the design of novel immunosuppressors for treating autoimmune hepatitis.