Synthesis and cytotoxic evaluation of amide derivatives of gambogic acid

A series of amide derivatives (3a–3h) were synthesized by coupling gambogic acid with various amines under mild PyBOP/DIPEA-mediated conditions. The cytotoxic activities of these derivatives were evaluated against HGC-27 (gastric carcinoma), Hep-G2 (hepatocellular carcinoma), and Vero (normal kidney) cell lines using the MTT assay. Several derivatives demonstrated enhanced cytotoxicity compared to GA, particularly compounds 3h, 3f, and 3b, which showed IC₅₀ values of 11.63, 12.84, and 13.82 µM, respectively, against HGC-27 cells.