Ricin in castor bean (Ricinus communis L.) seeds: A review on its anticancer activity and the role of cytotoxicity enhancers

Ribosome-inactivating proteins (RIPs) are toxins that are capable to permanently inhibit the synthesis of protein. RIP type II is a heterodimeric protein consisting of an A subunit linked to a lectin-like B chain by a disulfide bridge. Ricin contained in the seeds of Ricinus communis L. is a type II RIP which possesses cytotoxicity activity. However, due to the non-selectivity of the B-lectin chain, ricin needs delivering-vehicles to enhance its cytotoxicity. This article is devoted to reviewing the anticancer activity of ricin in castor bean seeds (a plant type II RIPs) and its various types of cytotoxicity enhancers.