From root of Cocculus trilobus DC. and C. sarmentosus Diels, Menispermaceae: Tomita et al., J. Pharm. Soc. Jpn. 48, 83 (1928); 50, 127 (1930); 62, 468, 481 (1942). Structure: Kondo, Tomita, Ann. 497, 104 (1932); Inubushi, Nomura, Tetrahedron Lett. 1962, 1133. Total synthesis of trilobine and isotrilobine: Y. Inubushi et al., Chem. Pharm. Bull. 25, 1636 (1977).