Studies on the large scale synthesis and anti-tumor activity of YSL

H-Tyr-Ser-Leu-OH (YSL), isolated from the degradation products of porcine spleen, was synthesized by a solution method on a large scale via two synthetic strategies. Its structure was confirmed by spectroscopic and related analyses. The in vivo anti-tumor activity was evaluated with murine H22 tumor models. The result indicated that, with the administration of YSL, the survival time of the murine H22 implanted mice was significantly prolonged.