Cancer-preventive Properties of an Anthocyanin-enriched Sweet Potato in the APCMIN Mouse Model

Abstract

Background: Anthocyanin-rich foods and preparations have been reported to reduce the risk of life-style related diseases, including cancer. The SL222 sweet potato, a purple-fleshed cultivar developed in New Zealand, accumulates high levels of anthocyanins in its storage root.

Methods: We examined the chemopreventative properties of the SL222 sweet potato in the C57BL/6J-APC ^MIN/+ (APC^MIN) mouse, a genetic model of colorectal cancer. APC^MIN and C57BL/6J wild-type mice (n=160) were divided into four feeding groups consuming diets containing 10% SL222 sweet potato flesh, 10% SL222 sweet potato skin, or 0.12% ARE (Anthocyanin rich-extract prepared from SL222 sweet potato at a concentration equivalent to the flesh-supplemented diet) or a control diet (AIN-76A) for 18 weeks. At 120 days of age, the mice were anaesthetised, and blood samples were collected before the mice were sacrificed. The intestines were used for adenoma enumeration.

Results: The SL222 sweet potato-supplemented diets reduced the adenoma number in the APC^MIN mice.

Conclusions: These data have significant implications for the use of this sweet potato variant in protection against colorectal cancer.

Keywords: APCMIN mice; Anthocyanins; Colorectal cancer; Sweet potato; cancer Protection.

Figure 1

SL222 purple sweet potato. (A) Storage root. (B) Chemical structures of anthocyanidine.

Figure 2

High-performance liquid chromatography analysis. (A) Anthocyanine profile of fresh aqueous extract from SL222 sweet potato. (B) Anthocyanine profile of anthocyanin-rich extract after several weeks of storage.

Figure 3

Body weights of animals. (A) Body weight of male wild-type and APC^MIN mice for the indicated diet groups at 18 weeks. Data represent mean ± SD. ARE, anthocyanin-rich extract. *P < 0.0001 vs. wild-type mice with the same diet, **P < 0.001 vs. control diet in wild-type mice, ***P < 0.01 vs. control diet in APC^MIN. (B) Body weight of female wild-type and APC^MIN mice for the indicated diet groups at 18 weeks. Data represent mean ± SD. *P < 0.0001 vs. wild-type mice, **P < 0.001 vs. control diet in wild-type mice, ***P < 0.01 vs. control diet in APC^MIN.

Figure 4

Typical appearance of intestinal adenomas under a dissecting microscope in the APC^MIN mouse (5× magnification). (A) A polyp in the small intestine, which is sessile in appearance (arrowhead). (B) A polyp in the colon, which is polypoid in appearance (arrowhead).

Figure 5

Effect of anthocyanin-rich diets on the number of intestinal adenomas in APC^MIN mice. Mice were fed the indicated diets in utero for 18 weeks before polyps were enumerated in the small intestine and colon. Data represent mean ± SD. ARE, anthocyanin-rich extract. *P < 0.0001 vs. control diet, **P < 0.001 vs. diet with flesh or skin.