Euphabeones A–D, Rearranged Jatrophane Diterpenoids from Euphorbia hylonoma : Isolation, Structural Elucidation, and Anti-Senescence Evaluation

Euphabeones A–D (1–4), four rearranged jatrophane diterpenoids, were isolated from Euphorbia hylonoma. 1 and 2 possess a new 1(15→14),13(14→15)-diabeo-jatrophane skeleton featuring a 16-oxatricyclo[11.2.1.01,11]hexadecane core, while 3 and 4 are rare 1(15→14)-abeo-jatrophanes. Their structures were established by spectroscopic analysis, ECD calculation, and single-crystal X-ray diffraction. A plausible biosynthetic pathway for 1–4 was proposed and supported by biomimetic skeletal conversion. Compound 2 exhibited potent antisenescence activity, effectively ameliorating senescence phenotypes both in vitro and in vivo.