Bioavailability of crude ricin in food matrices

AGFD 64

Luisa W. Cheng, lwcheng@pw.usda.gov1, David L. Brandon, dbrandon@pw.usda.gov1, Xiaohua He, xiaohua@pw.usda.gov1, Grace Q. Chen, qhgc@pw.usda.gov2, and J. Mark Carter, mcarter@pw.usda.gov1. (1) Foodborne Contaminants Research Unit, Western Regional Research Center, USDA Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, (2) Western Regional Research Center, USDA-Agricultural Research Service, 800 Buchanan St, Albany, CA 94710
Ricin (RCA-II or RCA60), one of the most potent toxins and documented bioweapons, is derived from castor beans of Ricinus communis L. Ricin is a type II ribosome-inactivating protein with dimeric AB chains. The A-chain is the cytotoxic component, while the B-chain is a galactose-binding lectin. Crude castor bean extracts contain another related lectin: Ricinus communis agglutinin (RCA-1 or RCA120), a tetrameric protein that is structurally similar to ricin, but has reduced toxicity. This study was undertaken to determine whether LD50 doses established using purified ricin accurately reflect the toxicity of the crude toxin in a complex food matrix. The toxicity of crude ricin extracts derived from two castor bean lines were compared with that of purified ricin. The contributions of RCA-1 and other components of castor beans to the stability and bioavailability of ricin in several food matrices in mouse intraperitoneal and intragastric models will be presented.

 

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Division of Agricultural & Food Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006