Abstract:
In this study, six triterpenoids were isolated from the stem of Diospyros gracilis H.R.Fletcher (Ebenaceae), including two friedelane-type triterpenoids namely friedelin and epifriedelanol, and four lupane-type triterpenoids namely lupeol, betulin, betulinic acid and betulinaldehyde. Their chemical structures were identified by spectroscopic analysis (IR, NMR and MS) and comparison with those reported in the literature. In the investigation for their in vitro cytotoxic activity against cancer cells, lupeol, betulin and betulinic acid exhibited cytotoxic effects against glioblastoma (U87) and breast cancer (MDA-MB231) cells (IC50 = 13.16, 15.39, 8.31 µM and 34.41, 74.49, 43.88 µM, respectively). In addition, lupeol and betulinic acid were found to cause suppression of the production of interleukin 2 by Jurkat T cells, stimulated with anti-CD3 and anti-CD28 antibodies, at a non-cytotoxic concentration, indicating their possible inhibitory activity on T cell activation mediated by CD3/CD28.
