We report the isolation of isonoyaine (1), a new C-ring secoculxine alkaloid, from Sarcocapnos soerabensis. Its structure was established on the basis of its spectroscopic data and confirmed by total synthesis. As a continuation of our work on the alkaloid content of Sarcocapnos species, we now report the isolation of a new C-secoberbine alkaloid, isonoyaine (1), from Sarcocapnos soerabensis Mateo & Figuerola (Fumariaceae). Its structure was established on the basis of its spectroscopic data and confirmed by total synthesis.