Male Swiss albino mice were subcutaneously injected with 500 micro-L of Matrigel alone or with VEGF (50 ng/mL) and/or acacetin (25 or 50 mg/kg bw). Mice were sacrificed 14 days later and the Matrigel plugs were removed, weighed and measured. Acacetin strongly suppressed VEGF-induced angiogenic growth into the Matrigel plugs after two weeks of treatment.

Aromatase was isolated from HepG2 cell lysates and prepared in a reaction mixture consisting of 5 l of 50 mM NADPH, 5 l [1-3H]-androst-4-ene-3,17-dione and 80 micro-L cell lysate (100 - 200 micro-g/mL of protein) with 10 microL of purified acacetin (1 - 50 micro-M). The reaction was initiated at 37 ◦C by addition of NADPH to the reaction mixtures and the incubation was continued for 1 h. The enzyme reaction was terminated by adding 500 l of chloroform. The mixture was immediately centrifuged and the aqueous layer extracted for scintillation counting. Acacetin showed potent inhibition of aromatase with an IC50 of 18.7 micro-M.