Alkaloids from Oxytropis ochrocephala and antiproliferative activity of sophoridine derivatives against cancer cell lines

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.