Synthesis, Characterization, and Biological Activity Studies on Fanlizhicyclopeptide A

The synthesis of a proline-rich cyclic heptapeptide, fanlizhicyclopeptide A (8), previouslyisolated from the fruits of Annona squamosa (sugar-apples), is described via coupling oftetrapeptide l-prolyl-l-tyrosyl-l-leucyl-l-proline methyl ester with tripeptide Boc-glycyl-lvalyl-l-proline followed by cyclization of the linear fragment having seven amino acid units.Structure of the synthesized cyclooligopeptide was confirmed by the means of chemical andspectroscopic methods including FTIR, 1H NMR, 13C NMR, FABMS and further, subjected tothe anthelmintic, antibacterial and the antifungal activity studies. Bioactivity results indicatedthat the newly synthesized cyclic peptide displayed potent anthelmintic activity against the threeearthworm species Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus eugeniaeat 2 mg/mL and remarkable anti-dermatophytic activities against Trichophyton mentagrophytesand Microsporum audouinii at concentration of 6 μg/mL.