Ten alkaloids (1–10), with sophoridine (1) as the most abundant component, were obtained from the
whole plants of Oxytropis ochrocephala Bunge. Furthermore, eight new sophoridine derivatives (11–16,
20, 21), with modification on the C-14 position of 1 were synthesized. All compounds (1–16, 20, 21) were
evaluated for antiproliferative activity against five human tumor cell lines. Among them, the newly
synthesized derivative 20 exhibited the best inhibitory activity against the tested cell lines. Its activity
was increased by more than fourfold as compared with parent compound 1