Synthetic and pharmacological studies on longicalycinin A.

Present investigation describes the synthesis of a natural phenylalanine-rich cyclopolypeptide longicalycinin A (10) by coupling of dipeptide unit Boc-L-phe-L-tyr-OH with tripeptide unit L-pro-L-phe-gly-OMe followed by cyclization of linear segment. Synthesized cyclic pentapeptide was characterized by spectral techniques including FTIR, 1H/13C NMR, FAB MS and elemental analysis and screened for different pharmacological activities. It was found that it has good anthelmintic activity against Megascoplex konkanensis, Pontoscotex corethruses and Eudrilus sp. at 2 mg/ml concentration, in addition to high cytotoxicity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines with CTC50 values of 2.62 and 6.37 microM. Dermatophytes were found to be moderately sensitive towards newly synthesized peptide.