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In vitro anticancer activity of fruit extracts from Vaccinium species
J Bomser1, D L Madhavi, K Singletary
1Department of Food Science and Human Nutrition, University of Illinois, Urbana 61801, USA.
Abstract:
Fruit extracts of four Vaccinium species (lowbush blueberry, bilberry, cranberry, and lingonberry) were screened for anticarcinogenic compounds by a combination of fractionation and in vitro testing of their ability to induce the Phase II xenobiotic detoxification enzyme quinone reductase (QR) and to inhibit the induction of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis, by the tumor promoter phorbol 12-myristate 13-acetate (TPA). The crude extracts, anthocyanin and proanthocyanidin fractions were not highly active in QR induction whereas the ethyl acetate extracts were active QR inducers. The concentrations required to double QR activity (designated CDqr) for the ethyl acetate extracts of lowbush blueberry, cranberry, lingonberry, and bilberry were 4.2, 3.7, 1.3, and 1.0 microgram tannic acid equivalents (TAE), respectively, Further fractionation of the bilberry ethyl acetate extract revealed that the majority of inducer potency was contained in a hexane/chloroform subfraction (CDqr = 0.07 microgram TAE). In contrast to their effects on QR, crude extracts of lowbush blueberry, cranberry, and lingonberry were active inhibitors of ODC activity. The concentrations of these crude extracts needed to inhibit ODC activity by 50% (designated IC50) were 8.0, 7.0, and 9.0 micrograms TAE, respectively. The greatest activity in these extracts appeared to be contained in the polymeric proanthocyanidin fractions of the lowbush blueberry, cranberry, and lingonberry fruits (IC50 = 3.0, 6.0, and 5.0 micrograms TAE, respectively). The anthocyanidin and ethyl acetate extracts of the four Vaccinium species were either inactive or relatively weak inhibitors of ODC activity. Thus, components of the hexane/chloroform fraction of bilberry and of the proanthocyanidin fraction of lowbush blueberry, cranberry, and lingonberry exhibit potential anticarcinogenic activity as evaluated by in vitro screening tests.
Insights
Fruit extracts from Vaccinium species show potential anticarcinogenic properties. Ethyl acetate extracts induce quinone reductase (QR), while proanthocyanidin fractions inhibit ornithine decarboxylase (ODC) activity, suggesting cancer-protective effects.
Area of Science:
- Nutritional Biochemistry
- Cancer Chemoprevention
- Phytochemistry
Background:
- Berries, particularly Vaccinium species, are rich in bioactive compounds.
- Understanding their role in cancer prevention requires identifying specific active components.
- Phase II detoxification enzymes and polyamine synthesis are key targets in cancer research.
Purpose of the Study:
- To screen fruit extracts of four Vaccinium species for anticarcinogenic compounds.
- To evaluate their ability to induce quinone reductase (QR) and inhibit ornithine decarboxylase (ODC).
- To identify specific fractions with potential cancer-preventive activities.
Main Methods:
- Fractionation of fruit extracts from lowbush blueberry, bilberry, cranberry, and lingonberry.
- In vitro testing for QR induction and ODC inhibition.
- Assay of enzyme activity using tannic acid equivalents (TAE) for quantification.
Main Results:
- Ethyl acetate extracts were potent inducers of QR activity, with bilberry showing the highest potency.
- Crude extracts and proanthocyanidin fractions effectively inhibited ODC activity.
- Specific fractions, including bilberry's hexane/chloroform subfraction and proanthocyanidins from other berries, demonstrated significant activity.
Conclusions:
- Components within Vaccinium species fruit extracts possess anticarcinogenic potential.
- Bilberry hexane/chloroform fractions and berry proanthocyanidins are promising candidates for further investigation.
- These findings support the role of berries in cancer chemoprevention strategies.