Chemical constituents of Aristolochia constricta: antispasmodic effects of its constituents in guinea-pig ileum and isolation of a diterpeno-lignan hybrid. - Zhang,G.; Shimokawa,S.; Mochizuki,M.; Kumamoto,T.; Nakanishi,W.; Watanabe,T.; Ishikawa,T.; Matsumoto,K.; Tashima,K.; Horie,S.; Higuchi,Y.; Dominguez,O.P. (J Nat Prod, 2008)