Two new alkaloids, 9-methoxy-18,19-dehydrocamptothecin (1) and 5- hydroxymappicine-20-O-beta-glucopyranoside (2a/2b as a racemic mixture), together with nine known compounds: camptothecin (3), 9-methoxy-camptothecin (4), 5-hydroxycamptothecin (5a/5b racemic mixture), 5-hydroxy-9-methoxycamptothecin (6a/6b racemic mixture), diosmetin (7), apigenin (8), apigenin-7-O-glucopyranoside (9), rosin (cinnamyl-O-beta-D-glucopyranoside) (10) and amarantholidoside IV (11) were isolated from the immature seeds of Nothapodytes foetida (Wight) Sleumer. The structures were elucidated by spectroscopic analyses. In the present research, compounds 1, 3, 4, 5a/5b and 6a/6b, also showed in vitro cytotoxicity against six cancer cell lines (HepG2, Hep3B, MDA-MB- 231, MCF-7, A549, and Ca9-22). Among them, compound 1 exhibited significant cytotoxicity against these cancer cell lines, with IC(50) of 0.24-6.57 microM. Furthermore, HPLC profiles were developed for qualitative and quantitative analysis of these active constituents in different parts of this plant, including mature and immature seeds, leaves, stems and roots. The results revealed that compounds 3 and 4 have the highest concentrations, which are found in the roots part of the plant.