Synthesis and biological activity of a cyclic hexapeptide from Dianthus superbus

Plant-originated cyclopolypeptide (XIII) was synthesized by coupling of dipeptide Boc-L-phe-OH and tetrapeptide gly-L-leu-L-ala-L-tyr-OMe followed by cyclization of a linear hexapeptide segment. Structure elucidation of XIII was done on basis of detailed spectral analysis including FTIR, (1)H NMR, (13)C NMR, FAB MS and elemental analysis. From the results of pharmacological screening, it was concluded that XIII possesses high cytotoxic activity against DLA and EAC cell lines with CTC(50) values of 15.1 mu M and 18.6 mu M, and potent antimicrobial activity against pathogenic fungi C. albicans with MIC of 6 mu g mL(-1). Moreover, XIII possesses moderate anthelmintic activity against earthworms M. konkanensis, P. corethruses, and Eudrilus sp. at 2 mg mL(-1) dose level. (C) 2008 Institute of Chemistry, Slovak Academy of Sciences.