[Note: quercetin is a plant-derived ‘flavonoid’ chemical (plentiful in green & black tea, red wine & grapes, onions, apples, broccoli, etc.) and studies indicate it supports anti-inflammatory and antioxidant processes, according to the American Cancer Society.]
Numerous in vitro studies argue for quercetin's chemopreventive potential in colon cancer; however, experimental studies in rodents are limited.
Macrophages play a role in tumorigenesis [tumor formation], but the effects of quercetin on macrophage infiltration in colon cancer is unknown. [When T cells recognize tumor cells, they activate macrophages whose job it is to engulf and digest cells in the local area. Thus macrophage activation is a measure of tumor cell activity.]
We examined the effects of quercetin on intestinal polyp multiplicity and macrophage number in Apc(Min/+) mice. [A special mutant mouse strain that develops colon cancer.]
Apc(Min/+) mice were assigned to placebo or quercetin (n = 8/group) groups.
Mice were given a placebo or quercetin (0.02%) diet from 4 to 20 weeks of age, after which:
• Intestines were analyzed:
- For polyp number and size in the small intestine (Sections 1-4) and colon (Section 5)
- And for macrophage number in the small intestine (Sections 1 and 3).
• Spleen weight was determined as a marker of systemic inflammation.
Quercetin decreased total intestinal polyps by 67% (P < 0.05).
Specifically, quercetin reduced intestinal polyps in categories >2 mm (69%) and 1-2 mm (79%; P < 0.05), and in Sections 2 (75%), 3 (80%), and 4 (79%; P < 0.05).
Quercetin also decreased macrophage number in Sections 1 (57%) and 3 (81%), and spleen weight (P < 0.05).
These data suggest that quercetin can reduce polyp number and size distribution in the Apc(Min/+) mouse and that these effects may be related to a reduction in macrophage infiltration.
Source: Nutrition and Cancer, Mar 2011;1(1). PMID: 21391122, by Murphy EA, Davis JM, McClellan JL, Carmichael MD. Department of Pathology, Microbiology, and Immunology, School of Medicine, University of South Carolina, Columbia, South Carolina, USA.