5,7,3',5'-tetrahydroxy-6,4'-dimethoxyflavone exhibits anti-HIV-1 activity in the anti-syncytium assay using (∆Tat/rev)MC99 virus and 1A2 cell line system, it shows considerably activity against HIV-1 reverse transcriptase. It exhibits cytotoxic activity against P-388 cell lines, it can inhibit DNA topoisomerase IIα activity, which may be responsible for the observed cytotoxicity.
6'7'-Epoxybergamottin is a furanocoumarin found in grapefruit. It is a potent inhibitor of the cytochrome P450 (CYP) isoform CYP3A4 with an IC50 value of 0.30 ppm in a cell-free assay, 0.33 μM in HL7 human liver cells, and 0.22 μM in S9 human intestine cells. It has been studied in the context of drug interactions with grapefruit constituents. It is found in grapefruit juice at concentrations of 0.1-7.4 μM and inhibits the transport of talinolol , a permeability glycoprotein (P-gp/ABCB1) transporter substrate, across Caco-2 cell monolayers (IC50 = 0.7 μM). 6'7'-Epoxybergamottin also has insecticidal properties with a concentration of 5 μg/cm2 leading to 100% mortality of adult olive fruit flies.
6',7'-Dihydroxybergamottin is a potent inhibitor of CYP3A activity, and may be primarily responsible for the effects of grapefruit juice on cytochrome P450 activity in humans.