Naringin is a flavonoid compound found in grapefruit, naringin gives grapefruit its characteristic bitter flavor. Grapefruit processors attempt to select fruits with a low naringin content, and often blend juices obtained from different grapefruit varieties to obtain the desired degree of bitterness. Naringin is believed to enhance our perception of taste by stimulating the taste buds (some people consume a small amount of grapefruit juice before a meal for this reason).
Naringin may be instrumental in inhibiting cancer-causing compounds and thus may have potential chemotherapeutic value. Nnaringin interferes with enzymatic activity in the intestines and, thus, with the breakdown of certain drugs, resulting in higher blood levels of the drug. A number of drugs that are known to be affected by the naringin in grapefruit include calcium channel blockers, estrogen, sedatives, medications for high blood pressure, allergies, AIDS, and cholesterol-lowering drugs. Caffeine levels and effects of caffeine may also be extended by consuming grapefruit or grapefruit juice. While the effect of naringin on the metabolism of a drug can increase the drug's effectiveness, it can also result in dosages that are inadvertently too high. Therefore, it's best not to take any drugs with grapefruit juice unless the interaction with the drug is known. In addition, the effects of drinking grapefruit juice is cumulative, which means that if you drank a glass of grapefruit juice daily with your medication for a week, the drug interaction would be stronger at the end of the week than at the beginning.