[Discovery of Novel Biologically Active Compounds of Natural Origin, with a Focus on Anti-tumor Activity]

Numerous clinically valuable medicines, including anticancer drugs, have been developed from biologically active natural compounds and their structurally related derivatives. This review discusses novel natural compounds with promising biological activities and those with novel chemical structures. Glaziovianin A, an isoflavone isolated from the leaves of Ateleia glazioviana (Legminosae), inhibited cell cycle progression at the M-phase with an abnormal spindle structure. AU-1 and YG-1, 5β-steroidal glycosides isolated from the whole plants of Agave utahensis and the underground parts of Yucca glauca (Agavaceae), induced apoptosis of HL-60 cells via caspase-3 activation. Lycolicidinol, an alkaloid isolated from the bulbs of Lycoris albiflora (Amaryllidaceae), induced transient autophagy and morphological changes in mitochondria in the early stage of the apoptotic cell death process in HSC-2 cells. Taccasterosides isolated from the rhizomes of Tacca chantrieri (Taccaceae) and stryphnosides isolated from the pericarps of Stryphnodendron fissuratum (Legminosae) are steroidal and triterpene glycosides with unique chemical structures having novel sugar sequences.