Opium alkaloid noscapine is an antitumor agent that arrests metaphase and induces apoptosis in dividing cells - Ye, K Q; Ke, Y; Keshava, N; Shanks, J; Kapp, J A; Tekmal, R R; Petros, J; Joshi, H C (Proc Natl Acad Sci U S A, 1998)