Iridoids and sfingolipids from Hedyotis diffusa

Seven new compounds were isolated from the aerial part of Hedyotis diffusa, including three iridoid glycosides, hedyoiridoidside A - C (1-3), two cerebrosides, hedyocerenoside F (4) and G (5), and two new ceramides, hedyoceramide A (6) and B (7). And six known iridoid glycosides (8-13) were also obtained. Their structures were established by their physico-chemical constants and spectroscopic analysis. The cytotoxicity of all compounds against tumor cell lines of human cervical cancer HeLa, human leukemia HL-60, human lung cancer A459, human hepatoma HepG2, human gastric gland carcinoma BCG-823, human nasopharyngeal cancer CNE-2, human colon cancer HCT15, and human prostate cancer PC-3 were also evaluated in vitro. As a result, new compound 1 exhibited evident cytotoxicity to all tumor cell lines, and the IC₅₀ values are from 9.5μM to 28.2μM, while new compound 2 exhibited evident cytotoxicity to Hela, HL-60, A459, HepG2, BGC-823, CNE-2, and HCT15, and the IC₅₀ values are from 15.8μM to 26.2μM. Known compound 11 also exhibited evident cytotoxicity to HL-60, A459, HepG2, BGC-823, CNE-2, and HCT15, and the IC₅₀ values are from 16.5μM to 40.4μM. New compounds 4-7 and known compounds 12 and 13 showed moderate cytotoxicity to some tumor cell lines.