Synthetic studies on cyclic octapeptides: Yunnanin F and Hymenistatin

Two biologically active cyclic peptides, Yunnanin F 8 and Hymenistatin 16 were synthesized and the structures were established on the basis of analytical, IR, NMR and mass spectral data. The newly synthesized compounds were screened for their antimicrobial and pharmacological activities. These cyclic octapeptides have shown moderate to good growth inhibition against bacterial strains and weak activity against fungal strains more than that of the standard drug against only Pseudomonas aeruginosa but weak to moderate activity against remaining three bacterial strains. They have shown very weak activity against fungal strains. Yunnanin F possessed good anthelmintic activity while Hymenistatin possessed very low activity, but both showed moderate anti-inflammatory activity.