Synthesis of a phenylalanine-rich peptide as potential anthelmintic and cytotoxic agent.

A natural cyclic heptapeptide segetalin D [VIII] was synthesized by coupling of tripeptide unit Boc-Pro-Gly-Leu-OMe [V] with tetrapeptide unit Boc-Ser-Phe-Ala-Phe-OMe [VI] after proper deprotection at carboxyl and amino ends followed by cyclization of linear peptide segment. Structure of VIII was confirmed by spectral and elemental analyses. The newly synthesized cyclopeptide was tested for its antibacterial, antifungal, anthelmintic and cytotoxic activities. Compound VIII showed high cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines with CTC50 values of 7.54 and 13.56 microM. Moreover, VIII exhibited potent anthelmintic activity against earthworms Eudrilus species, Megascoplex konkanensis and Pontoscotex corethruses at a dose of 2 mg/mL.