Total Synthesis of a Natural Cyclooligopeptide From Fruits of Sugar-Apples

Abstract

A cyclopentapeptide, fanlizhicyclopeptide B, previously isolated from the fruits of Annona squamosa, was synthesized via coupling of dipeptide l-Isoleucyl-l-Tyrosyl methyl ester with tripeptide Boc-lAlanyl-Glycyl-l-Proline followed by cyclization of the linear pentapeptide fragment. Structure of the synthesized cyclooligopeptide was confirmed using quantitative elemental analysis, FTIR, 1 H NMR, 13 C NMR and mass spectrometry. Results of pharmacological activity studies indicated that the newly synthesized cyclopentapeptide displayed remarkable anthelmintic potential against Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus eugeniea at 2 mg/ml and potent antidermatophytic activities against Trichophyton mentagrophytes and Microsporum audouinii at concentration of 6 mcg/ml.