Synthesis and anti-tumor evaluation of novel 25-hydroxyprotopanaxadiol analogs incorporating natural amino acids

A series of 25-OH-PPD derivatives have been synthesized and their anti-tumor activities were evaluated against a panel of human tumor cell lines in vitro. Combining an ester group combined with the presence of an amino acid moiety led to a 10-fold improved anti-tumor activity. [Display omitted] ► A series of 25-OH-PPD analogs incorporating natural amino acids have been synthesized. ► Combining an ester group combined with the presence of an amino acid moiety led to a 10-fold improved anti-tumor activity. ► Some compounds showed stronger anti-tumor activities than 5-Fu in vitro. In the current study, derivatives of 25-hydroxyprotopanaxadiol (25-OH-PPD) were prepared and their in vitro anti-tumor activities were tested on six different human tumor cell lines by standard MTT assay. The results showed that combining an ester group combined with the presence of an amino acid moiety led to a 10-fold improved anti-tumor activity. Compound 1c exhibited the best anti-tumor activity in the in vitro assays. Compounds 2c, 3c, 4c, 5c, 6c and 8b showed better anti-tumor activities compared to the parent compound 25-OH-PPD. The current results may provide useful data for researching and developing new anti-cancer agents.