6,7-Dihydroxybergamottin is a furanocoumarin that occurs naturally in grapefruit and some other citrus fruits. It strongly blocks the CYP3A4 enzyme in the gut and liver. Many common medications depend on that same enzyme to break down properly.
People do not take this compound for a direct health benefit. Supply of the ingredient inside a supplement usually is not meant to deliver nutrition or therapy. Most human exposure comes from eating grapefruit or drinking grapefruit juice.
Blocking CYP3A4 can drive up blood levels of medicines that rely on it, sometimes to dangerous concentrations. This interaction shows up clearly with some statins, calcium channel blockers, immunosuppressants, and other prescription drugs.