Design and synthesis of tryptophan containing peptides as potential analgesic and anti-inflammatory agents

A new series of smaller peptides with tryptophan at C-terminal and varying N-protected amino acids/peptides were designed, synthesized and characterized by analytical and spectroscopic techniques. Analgesic and anti-inflammatory properties of these peptides were carried out in vivo using tail-flick method and carrageenan-induced paw edema method, respectively, at different doses and different time intervals. Most of the peptides synthesized displayed enhanced activity, and particularly tetra and hexapeptides 29-31 were found to be even more potent than the reference standards used. Moreover, some peptides have exhibited promising activity even after 24 h of administration, whereas the reference standards were active only up to 3 h. Further, the compounds did not present any ulcerogenic liability.