Ricin detoxification in castor (Ricinus communis L.) seeds: Current advances, integrated strategies, and future directions

Castor bean (Ricinus communis L.) is a key industrial crop valued for its non-edible oil rich in ricinoleic acid. However, the presence of ricin - a type II ribosome-inactivating protein (RIP)-in the seed endosperm remains a major bottleneck for valorizing the protein-rich de-oiled cake (~20-25% protein) as animal feed. Ricin is highly toxic, with an LD50 of ~1-5 µg/kg in humans, and poses significant risks to human and animal health, thereby limiting the crop's commercial potential. Traditional detoxification methods, including physical (thermal), chemical (alkali/acid), and enzymatic treatments offer limited efficacy, often compromising protein quality or leaving toxic residues. Recent advances in plant genomics and molecular biology have facilitated the identification and characterization of ricin and RCA gene families, enabling targeted gene silencing and editing approaches. RNA interference (RNAi), antisense suppression, and CRISPR/Cas9-mediated knockouts have demonstrated promising results in reducing ricin expression while maintaining normal seed development and oil composition. Novel strategies such as promoter engineering, tissue-specific expression control, and base editing are emerging as powerful tools for generating transgene-free, low-ricin castor lines. Additionally, microbial degradation using enzymes and biotransformation pathways offers eco-friendly and scalable alternatives. This review discusses the current knowledge on the structure and biosynthesis of ricin, its mechanisms of toxicity, and highlights the latest strategies and technological interventions aimed at detoxifying castor bean seeds. We also evaluate the advantages, limitations, and regulatory challenges of these approaches and propose future research directions for sustainable, safe, and economically viable detoxification of castor products.