Naringenin (not to be confused with naringin) is a flavanone that is considered to have a bioactive effect on human health as antioxidant, free radical scavenger, anti-inflammatory, carbohydrate metabolism promoter, and immunity system modulater. This substance has also been shown to reduce oxidative damage to DNA in vitro. Scientists exposed cells to 80 micromoles of naringenin per liter, for 24 hours, and found that the amount of hydroxyl damage to the DNA was reduced by 24% in that very short period of time. Unfortunately, this bioflavonoid is difficult to absorb on oral ingestion. In the best case scenario, only 15% of ingested naringenin will get absorbed in the human gastrointestinal tract. A full glass of orange juice will supply about enough naringenin to achieve a concentration of about 0.5 micromoles per liter. There are speculations that, given more time at a lower concentration, it could have similar effects. Naringenin is present in grapefruits1.