Synthesis, Spectroscopic and Biological Investigation of Cyclic Octapeptide: Cherimolacyclopeptide G


Abstract: A natural cyclic octapeptide cherimolacyclopeptide G (8) was synthesized by coupling of tetrapeptide units Boc-Gly-Ala-Val-Pro-OMe (5) and Boc-Ile-Tyr-Ala-Pro-OMe (6) after proper deprotection at carboxyl and amino terminals followed by cyclization of the linear peptide segment. The structure was elucidated by IR, ^1H-NMR, ^{13}C-NMR, FAB MS spectral data, and elemental analyses. The newly synthesized cyclopeptide was also evaluated for its antimicrobial, anthelmintic, and cytotoxic activities and found to exhibit potent anthelmintic and cytotoxic activity against earthworms, Megascoplex konkanensis, Pontoscotex corethruses, and Eudrilus species, and Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines. In addition, compound 8 possessed moderate antimicrobial activity against the pathogenic fungus Candida albicans and gram-negative bacterium Pseudomonas aeruginosa.

Keywords: Cyclic octapeptide, cherimolacyclopeptide G, antibacterial activity, antifungal activity, anthelmintic activity, cytotoxicity

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