Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intestine and colon

Biological Activity of Extracts from Differently Produced Blueberry Fruits in Inhibiting Proliferation and Inducing Apoptosis of HT-29 Cells

For several decades, people have been searching for natural substances of plant origin that, when introduced into the diet, could strengthen immunity, have anticancer properties, and support conventional therapy. The development of agriculture with the implementation of various plant cultivation systems, apart from the economic aspect, results in the search for such cultivation conditions that would contribute to obtaining the most beneficial product for health. Therefore, the aim of our research is as follows: (a) to compare the antiproliferative activity and the ability to induce apoptosis of HT-29 cells by extracts from blueberry fruits deriving from different types of cultivation systems (conventional, organic, and biodynamic); (b) to examine whether the interaction of extracts with anticancer drugs used in the treatment of colorectal cancer is influenced by the type of cultivation, and (c) to investigate whether extracts obtained from fruits from subsequent years of cultivation retain the same biological activity. The results of our study are promising but inconclusive. A statistically significant difference occurred in only one of the two years of the study. The greatest inhibition of proliferation is observed for biodynamic cultivation compared to organic cultivation, while the highest levels of apoptosis and necrosis of HT-29 cells are induced by blueberry fruit extracts obtained from organic cultivation. The complementary effect of the extracts on the inhibition of HT-29 cell proliferation by anticancer drugs (5-FU and Erbitux) is not demonstrated. The induction of apoptosis by 5-FU is not enhanced by blueberry extracts, in contrast to necrosis. The level of apoptosis and necrosis induced by Erbitux is potentiated, but no dependence on crop type is shown. Blueberry fruit extracts from two consecutive years of cultivation did not maintain the same activity. A plausible reason for the variability in the composition and biological activity of fruit extracts obtained from two years of cultivation is the varying environmental conditions.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Traditional serrated adenomas and serrated carcinomas in carcinogen-treated rats

AIMS

A recent review of archived sections from early experiments in rats showed neoplasias exhibiting serrated configurations. The aim was to assess the frequency of serrated neoplasias in the colon and small intestine of carcinogen-treated rats.

METHODS

While reviewing archival sections from early experiments in Sprague-Dawley (SD) and Fisher-344 (F-344) rats, we recently detected colonic and intestinal traditional serrated adenomas (displaying serrated or microtubular patterns) and serrated carcinomas. SD rats were injected 1,2-dimethylhydrazine (DMH) for 27 weeks whereas F-344 rats were fed with a pyrolysate (GLU-1) for 24 months. Filed sections from 358 colonic and small intestinal neoplasias were re-evaluated.

RESULTS

DMH-treated SD rats had 215 colonic neoplasias (1.4% were serrated adenomas, 7.9% microtubular adenomas, 2.8% serrated carcinomas and 2.8% microtubular carcinomas). GLU1-treated F-344 rats had 53 colonic neoplasias (1.9% were serrated adenomas and 20.8% microtubular adenomas), and 89 small intestinal neoplasias (1.1% were serrated adenomas, 42.7% microtubular adenomas and 6.7%, microtubular carcinomas).

CONCLUSIONS

DMH/SD-rats develop serrated and microtubular adenomas and carcinomas in the colon, whereas GLU1/F-344 rats develop microtubular adenomas in the colon and microtubular adenomas and carcinomas in the small intestine. The two rat-settings emerge as suitable models to study the molecular attributes of serrated and microtubular neoplasias under the standard conditions of the laboratory. This study is the first showing that a substantial number of serrated and particularly microtubular adenomas and carcinomas develop in the colon and small intestine of experimental rats. Importantly, serrated and microtubular neoplasias in rats recreate the histology of duodenal and colonic traditional serrated neoplasias in human beings.

Evaluation of blueberry juice in mouse azoxymethane-induced aberrant crypts and oxidative damage

Blueberry is a plant with a number of nutritional and biomedical capabilities. In the present study we initially evaluated the capacity of its juice (BJ) to inhibit the number of aberrant crypts (AC) induced with azoxymethane (AOM) in mouse. BJ was administered daily by the oral route to three groups of animals during four weeks (1.6, 4.1, and 15.0 μL/g), respectively, while AOM (10 mg/kg) was intraperitoneally injected to the mentioned groups, twice a week, in weeks two and three of the assay. We also included two control groups of mice, one administered distilled water and the other the high dose of BJ. A significant increase of AC was observed in the AOM treated animals, and a mean protection of 75.6% was determined with the two low doses of BJ tested; however, the high dose of the juice administered together with AOM increased the number of crypts more than four times the value observed in animals administered only AOM. Furthermore, we determined the antioxidant potential of BJ with an ex vivo DPPH assay and found a dose-dependent decrease with a mean of 19.5%. We also determined the DNA oxidation/antioxidation by identifying 8-hydroxy-2'-deoxyguanosine adducts and found a mean decrease of 44.3% with the BJ administration with respect to the level induced by AOM. Our results show a complex differential effect of BJ related to the tested doses, opening the need to further evaluate a number of factors so as to determine the possibility of a cocarcinogenic potential.

DNA repair and the accumulation of oxidatively damaged DNA are affected by fruit intake in mice

AGING is associated with elevated oxidative stress and DNA damage. To achieve healthy aging, we must begin to understand how diet affects cellular processes. We postulated that fruit-enriched diets might initiate a program of enhanced DNA repair and thereby improve genome integrity. C57Bl/6 J mice were fed for 14 weeks a control diet or a diet with 8% peach or nectarine extract. The activities of DNA repair enzymes, the level of DNA damage, and gene expression changes were measured. Our study showed that repair of various oxidative DNA lesions was more efficient in liver extracts derived from mice fed fruit-enriched diets. In support of these findings, gas chromatography-mass spectrometry analysis revealed that there was a decrease in the levels of formamidopyrimidines in peach-fed mice compared with the controls. Additionally, microarray analysis revealed that NTH1 was upregulated in peach-fed mice. Taken together, these results suggest that an increased intake of fruits might modulate the efficiency of DNA repair, resulting in altered levels of DNA damage.