First Total Synthesis and Pharmacological Potential of a Plant Based Hexacyclopeptide.

A new bioactive proline-rich cyclohexapeptide - diandrine C (), previously isolated from whole plant of (Caryophyllaceae), was synthesized through coupling reactions of tetrapeptide unit Boc-Gly--Pro--Tyr--Trp-OH with dipeptide unit -Pro-Gly-OMe using -diisopropylcarbodiimide (DIPC) as the coupling agent, followed by cyclization of linear hexapeptide unit under alkaline condition. Structure of cyclohexapeptide was confirmed by means of chemical, and spectroscopic analyses and also was screened for its antimicrobial and anthelmintic properties. Bioevaluation results indicated that the newly synthesized hexacyclopeptide exhibited potent antimicrobial activity against Gram-negative bacteria , and pathogenic at 6 μg/mL. Moderate to good level of antihelmintic activity against three earthworm species , and was also observed at concentration of 2 mg/mL.