Bioflavonoids and cancer
Bioflavonoids, also known as flavonoids, are a diverse group of plant compounds recognized for their potential health benefits, particularly in the context of cancer prevention. These compounds, characterized by their unique chemical structure, can be found in a variety of foods such as fruits, vegetables, tea, and cocoa. Research has indicated that bioflavonoids possess anticarcinogenic properties, functioning as effective antioxidants that protect DNA and proteins from oxidative damage. They may also influence cellular processes by inhibiting the proliferation of cancer cells and promoting apoptosis, or programmed cell death.
Furthermore, bioflavonoids are thought to enhance the body’s ability to detoxify carcinogens and reduce inflammation, which is often linked to cancer progression. Although numerous animal studies have suggested a connection between high bioflavonoid intake and reduced cancer risk, human epidemiological studies have yielded mixed results. Despite the current lack of definitive evidence, there is ongoing research into the mechanisms of bioflavonoids and their role in cancer prevention, with particular attention on compounds such as quercetin and apigenin. As interest in bioflavonoids grows, further clinical trials are needed to establish dietary guidelines and fully understand their cancer-fighting potential.
On this Page
Subject Terms
Bioflavonoids and cancer
ALSO KNOWN AS: Flavonoids
DEFINITION: Flavonoids are the most common plant phenolic compounds. Their basic chemical structure consists of two benzene rings linked by a chain of three carbon atoms that can form a heterocyclic ring with oxygen. Variations of this chemical theme give rise to thousands of different bioflavonoids, which can be grouped into several families. Six families include bioflavonoids particularly common in the diet: flavonols, flavonones (or flavanones), isoflavones, flavones, chalcones, and anthocyanidins. Examples of bioflavonoids from each of these families are quercetin, catechin, hesperitin, genistein, apigenin, and cyanidin. Most of the plant bioflavonoids occur as glycosides—that is, they have a sugar attached.
Nutrition: The principal food sources of bioflavonoids include apples, celery, onions, tea, citrus fruits, berries, soy, red wine, and cocoa. Although bioflavonoids are resistant to heat, certain food manipulations, such as the peeling of fruits or boiling, can cause some loss of their content or bioavailability. After the sugar moiety is removed by enzymes of the gastrointestinal tract, a variable portion of the ingested bioflavonoids is readily absorbed. The absorbed bioflavonoids are metabolized in the liver by conjugation with other chemical groups (for example, glucuronic acid, sulfate, or methyl groups) and converted to smaller compounds.
Bioflavonoids and cancer: Numerous studies in experimental models, both in vivo and in vitro, have suggested that bioflavonoids have anticarcinogenic potential. As effective antioxidants, they prevent mutagenesis and tumor promotion by protecting deoxyribonucleic acid (DNA) and proteins from oxidative damage. By acting on signal transduction pathways that control the cell cycle, bioflavonoids inhibit proliferation and stimulate apoptosis—that is, programmed death—of human cancer cells. Cell cycle–related actions performed by bioflavonoids include suppressing nuclear factor kappa B activation, inhibiting mitogen-activated protein kinases, and blocking epidermal growth factor signaling. Bioflavonoids also stimulate detoxifying enzymes, such as cytochrome P450, which convert carcinogens into water-soluble compounds that can be eliminated from the body. In addition, they inhibit inflammation and angiogenesis.
There is also some scientific evidence that diets rich in fruits and vegetables protect against various forms of cancer. Animal studies have shown significant associations between high consumption of bioflavonoids and a reduced risk of certain forms of cancer, such as breast, gastrointestinal, lung, prostate, and skin cancers. However, several epidemiological studies in humans have failed to find such significant associations. Although bioflavonoids are gaining increasing acceptance as cancer-preventing agents, more consistent epidemiological data is needed before issuing specific public health guidelines.
As the twenty-first century progresses, the intricate mechanisms through which bioflavonoids potentially safeguard against cancer remain a subject of active investigation. More human clinical trials are necessary to fully understand the dietary requirements to obtain anti-cancer benefits from bioflavonoids. Still, in studies in the 2020s, bioflavonoids did appear to have anticancer properties due to their ability to trigger apoptosis (cell death), decrease tumor proliferation, and reduce oxidized stress. The antioxidant and anti-inflammatory aspects of bioflavonoids were apparent. Quercetin, kaempferol, myricetin, apigenin, and luteolin are examples of bioflavonoids that showed the most promise in ongoing studies, and a review of studies appeared to confirm bioflavonoid role in breast cancer prevention. Although more studies are needed, bioflavonoids hold promise as natural cancer-fighting substances.
Bibliography
“American Cancer Society Guideline for Diet and Physical Activity.” American Cancer Society, 9 June 2020, www.cancer.org/cancer/risk-prevention/diet-physical-activity/acs-guidelines-nutrition-physical-activity-cancer-prevention/guidelines.html. Accessed 21 June 2024.
Batra, Priya, and Anil K. Sharma. "Anti-cancer Potential of Flavonoids: Recent Trends and Future Perspectives." 3 Biotech, vol. 3, no. 6, 2013, pp. 439-459, doi.org/10.1007/s13205-013-0117-5. Accessed 21 June 2024.
Chabot, Guy G., et al. "Flavonoids in Cancer Prevention and Therapy: Chemistry, Pharmacology, Mechanisms of Action, and Perspectives for Cancer Drug Discovery." Alternative and Complementary Therapies for Cancer: Integrative Approaches and Discovery of Conventional Drugs. Ed. Moulay Alaoui-Jamali. New York: Springer, 2010.
Chen, Shen, et al. "A Review of Classification, Biosynthesis, Biological Activities and Potential Applications of Flavonoids." Molecules, vol. 28, no. 13, 2023, doi.org/10.3390/molecules28134982. Accessed 21 June 2024.
Kopustinskiene, Dalia M., et al. "Flavonoids As Anticancer Agents." Nutrients, vol. 12, no. 2, 2020, doi.org/10.3390/nu12020457. Accessed 21 June 2024.
Panche, A. N., et al. "Flavonoids: An Overview." Journal of Nutritional Science, vol. 5, 2016, doi.org/10.1017/jns.2016.41. Accessed 21 June 2024.
Spencer, Jeremy P. E., and Alan Crozier, eds. Flavonoids and Related Compounds: Bioavailability and Function. Boca Raton: CRC, 2012.