Gardenin B exhibits superior antiproliferative activity against lung, breast, colon, hepatic and leukaemia cell lines as well as in keratinocytes .

Here we investigated the antiproliferative activity of the flavonoids isolated from Baccharis scandens against human leukemia cell lines and found that the methoxyflavonoid Gardenin B was the most cytotoxic compound against HL-60 and U-937 cells, showing IC50 values between 1.6 and 3.0 μM, but had no significant cytotoxic effects against quiescent or proliferating human peripheral blood mononuclear cells. These effects on viability were accompanied by the concentration- and time-dependent appearance of apoptosis as evidenced by DNA fragmentation, formation of apoptotic bodies and a sub-G1 ratio increase. Comparative studies with the best-studied bioflavonoid quercetin indicate that Gardenin B is a more cytotoxic and more apoptotic inducer than quercetin. Cell death induced by Gardenin B was associated with: (i) a significant induction of caspase-2, -3, -8 and -9 activities; (ii) cleavage of the initiator caspases (caspase-2, -8 and -9), of the executioner caspase-3, and of poly(ADP-ribose) polymerase; and (iii) a concentration-dependent reactive oxygen species generation[1]