Naringenin, a flavonoid antioxidant compound, is found in citrus fruits and is the predominant flavonoid in grapefruit. Naringenin is notable for its ability to interfere with the activity of some pharmaceutical drugs by inhibiting a system in the liver where the drugs are broken down. Naringenin has also been shown to have some effects on cholesterol levels and blood vessel health. Check with your doctor before using naringenin to treat a medical condition.
Cholesterol-Lowering Capabilities
Naringenin showed significant cholesterol-lowering ability in a study conducted at the Department of Nutrition and Food Science, Kyungpook National University, South Korea. In the laboratory animal study, a high-cholesterol diet supplemented with naringenin for six weeks decreased cholesterol levels in the blood by about 20 percent. Activity of the enzyme HMG-CoA reductase, which controls cholesterol production, was lower in the naringenin-supplemented group compared to a control group.The study was published in the February 2003 issue of the journal "Bioorganic and Medicinal Chemistry."
HDL, LDL and Plaque
Researchers at the Danish Veterinary and Food Administration, Institute of Food Safety and Toxicology, Denmark found naringenin ineffective at lowering cholesterol in a study on laboratory animals published in the May 2001 issue of the "Journal of Lipid Research." In their study, diets supplemented with 0.2 percent naringenin for 16 weeks did not result in a decrease in total cholesterol or triglycerides. Naringenin did, however, increase levels of high-density lipoprotein, HDL, the good form of cholesterol, and decrease levels of low-density lipoprotein, LDL, the bad form of cholesterol. Additionally, naringenin-supplemented animals showed less plaque formation in their arteries than did a control group.
HDL Cholesterol
Naringenin and two related compounds exerted HDL-increasing effects in a laboratory animal study that appeared in the January 2007 issue of the journal "Translational Research." All three forms of naringenin also lowered total cholesterol and triglyceride levels. Activity of the enzyme HMG-CoA reductase was significantly inhibited in the study, and antioxidant activity of two key antioxidant enzymes used by the liver was significantly higher in all three groups. Researchers concluded that naringenin and its metabolites were effective at lowering cholesterol and increasing antioxidant activity in this preliminary animal-based study.
Protein Production
Naringenin and another principal citrus flavonoid antioxidant compound, known as hesperitin, reduce production of apolipoprotein B -- the protein structural backbone of LDL cholesterol -- according to Bela Buslig, co-editor of the book "Flavonoids in Cell Function." The flavonoid compounds also lower LDL levels. Both compounds exert cholesterol-lowering effects by reducing the availability of lipids that are required to assemble cholesterol molecules.
References
- "Bioorganic and Medicinal Chemistry"; Naringenin 7-o-cetyl Ether as Inhibitor of Hmg-coa Reductase and Modulator of Plasma and Hepatic Lipids in High Cholesterol-fed Rats; M. Lee, et al.; February 2003
- "Journal of Lipid Research"; 17beta-estradiol but Not the Phytoestrogen Naringenin Attenuates Aortic Cholesterol Accumulation in WHHL Rabbits; A. Mortensen, et al.; May 2001
- "Translational Research"; Hypocholesterolemic and Antioxidative Effects of Naringenin and Its Two Metabolites in High-cholesterol Fed Rats; S. Jeon, et al.; January 2007
- Flavonoids in Cell Function; Béla S. Buslig; 2002
- "American Journal of Physiology"; Bioavailability of the Flavanone Naringenin and Its Glycosides in Rats; Catherine Felgines, et al.; March 2000
- "Revista Medico-Chirurgicala"; Flavonoids -- Bioactive Compounds in Fruit Juice; D. Harapu, et al.; October 2010
