Search on seeds for drug discovery from medicinal plants

Plants and plant-derived preparations have been employed in the treatment of numerous and diverse medical conditions. Plants remain to this day one of the most important sources of biological active compounds and continue to provide drug discovery seeds. During our search for active ingredients from medicinal plants, we have isolated various kinds of cyclic peptides, polycyclic alkaloids, and terpenoids with various bioactivities as new drug discovery seeds [1 – 4]. In general, cyclic nature of them often give more stability, lipophilicity, and membrane permeability, because they lack zwitterionic feature. Restricted bond rotation create more rigid conformation, which can result in greater binding affinity and selectivity for target molecules. The structurally diverse alkaloids and peptides often possess unusual skeletons, and many of them continue to be of interest from biological points of view as well as providing challenging targets for structure determination and total synthesis. In this paper we describe the isolation, structure elucidation, and biological activity of some natural products with cyclic nature as new drug discovery seeds.

Keywords: Cyclic peptides, Alkaloids, Terpenoids, Biological activity.

References:

[1] Kobayashi J, Morita H. The Daphniphyllum alkaloids. Alkaloids Chem Biol 2003: 60: 165 – 205

[2] Kobayashi J, Morita H. The Lycopodium alkaloids. Alkaloids Chem Biol 2005; 61: 1 – 57

[3] Hirasawa Y, Kobayashi J, Morita H. The Lycopodium alkaloids. Heterocycles 2009; 77: 679 – 729

[4] Morita H, Takeya K. Bioactive cyclic peptides from higher plants. Heterocycles 2010; 80: 739 – 764