Inhibitory effects of #beta#-cryptoxanthin rich powder prepared from Satsuma mandarin (Citrus unshiu Marc.) juice on azoxymethane-induced aberrant crypt foci of rats

摘要

Inhibitory effects of the #beta#-cryptoxanthin rich powder (CRP) on azoxymethane (AOM)-induced aberrant crypt foci (ACF), which are precursor lesions for colon carcinoma, were studied. CRP containing 0.67% #beta#-cryptoxanthin was prepared from Satsuma mandarin (Citrus unshiu Marc.) juice. Male F 344 rats were given s.c. injections of AOM (20 mg/kg body wt) once a week for 2 weeks to induce ACF and they also received diets containing 0.5% CRP for 4 weeks. CRP feeding reduced the incidence of ACF by 20% after 4 weeks (P>0.01) and 18% after 11 weeks (P<0.005). In addition, the activities of glutathione S-transferase (GST) and quinone reductase (QR) in liver and colon of rats gavaged various doses of CRP (0, 40, 200 and 400 mg/kg body wt) for 5 days were assayed. CRP significantly increased the activities of GST and QR in the liver and colon. Suppression of ACF formation by CRP might relate to elevation in the phase II enzymes GST and QR of the liver and colon.