Recent Progress in Medicinal Investigations on Trichosanthin and other Ribosome Inactivating Proteins from the Plant Genus Trichosanthes

Ribosome inactivating proteins (RIPs) are toxic RNA N-glycosidases that cleave an adenine-ribose glycosidic bond at position adenine(4324) with the conserved ricin/α-sarcin loop in the eukaryotic 28S ribosomal RNA. RIPs have captured the attention of botanists, biochemists, and drug discoverers, due to their diverse potent defensive activities, and inter alia, their antitumor and anti-HIV activities. Out of the 145 families of plants, Trichosanthes ranks among the top 5 genera with a good potential of use for discovery of anticancer drugs. Trichosanthin (TCS) is a famous type I RIP purified from T. kirilowii that has been known for around 30 years. Based on the results of voluminous in vitro and in vivo investigations, TCS is considered a good candidate for the treatment of HIV/AIDS and neoplasms. Here we integrate recent progress of the research on the different medicinal activities of TCS. In addition to TCS, other promising RIPs from the same species (such as TAP29 and trichoanguin), and from the same genus Trichosanthes are included. This review presents a brief panorama of the studies on Trichosanthes RIPs. Regarding the debilitating nature of AIDS and different tumors, further understanding of these multifunctional proteins is worthwhile since it may help to open a novel therapeutic window for these stubborn diseases.