Chapter 4 Macrocyclic Peptide Alkaloids From Plants

Abstract

This chapter reviews macrocyclic peptide alkaloids in dealing with cyclic oligopeptides. To date, many macrocyclic peptides alkaloid have been isolated from plants. Alkaloids are sometimes described as a group of compounds usually containing tertiary or quaternary nitrogen atoms in their molecules and showing alkali and biological activities. Peptides have amide linkages in their molecules, so peptide alkaloids usually have the characteristics of both an alkaloid and a peptide. Cyclic oligopeptides possess antineoplastic activity; thus, a number of related compounds from Rubia spp. are isolated, which shows strong antineoplastic activity against Sarcoma 180A. Monocyclic oligopeptides, which comprise a five- to twelve amino acid moiety, have been isolated from many plants, including the families Compositae, Caryophyllaceae, and Linaceae. Biological activities have been evaluated, especially antitumor activity. The large number of natural products screened during the National Cancer Institute (NCI) program has also been discussed from an overview of the relationship of assessment between experimental analysis and clinical patients for drug development; also, the screening protocols for each tumor system have been well established. The chapter reviews many of the compounds having antineoplastic activity isolated from higher plants in Heterocycles. Finally, it describes the antitumor and cytotoxic cyclic oligopeptides of the higher plants selected from the screening tests.