The protective effect of Hizikia fusiformis on colon cancer in azoxymethane‐treated rats

Abstract

Hizikia fusiformis is a seaweed rich of soluble dietary fiber and phenol compounds which are known to have protective effects on gastrointestinal cancer. In this study, we evaluated the protective efficacy of dietary Hizikia fusiformis (HF) on colon cancer induced by azoxymethane(AOM) in rats. Hizikia fusiformis was dried in low‐temperature vacuum dryer and extracted with water (80_, 2hr, 120rpm). The extract was centrifuged (8,000rpm, 10min), filter and concentrated to 5°brix, which was added into AIN‐76A diet. The animals were assigned to 4 groups: the saline + AIN‐76A diet, AOM + AIN‐76A diet, AOM + AIN‐76A diet containing 1% CF extract, AOM + AIN‐76A diet containing 2% HF extract. All rats (male, F344) except saline controls received two AOM (15mg/kg body weight) injections via subcutaneous route; once at 6 weeks of age followed by another at 7 weeks of age. The extract of Hizikia fusiformis was added in diet of respective groups from 1 week after AOM injection until sacrifice. The number of colonic aberrant crypt foci (ACF) was reduced up to 50% in groups administered HF extract, however, the difference from the concentration was not observed. The proliferating cell nuclear antigen (PCNA) index was also significantly reduced in groups administered HF extract. Our results represent that the extract of Hizikia fusiformis have protective effect on AOM induced colon cancer in rats.