Isolation of bioactive constituents from Vaccinium myrtillus (bilberry) fruits and cell cultures

Tissues from bilberry (Vaccinium myrtillus L.) fruits and callus cultures were extracted and fractionated to investigate phytochemical bioactivity. Major fractions containing flavonoids (proanthocyanidins and anthocyanin pigments) and a hexane extract containing largely chlorophylls, carotenoids, sterols and lipids were isolated, and further screened for anticancer activity by in vitro testing of their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR) in murine hepatoma cells. Although flavonoid fractions were inactive in the assay, a clear, significant induction of QR activity resulted from testing the hexane extract. The concentration of the extract required to double QR specific activity was 9 mu g/150 mu l per well, which indicates that one or more components possess substantial QR-inducing capacity, comparable to known QR inducers such as furanone and catechol. beta-sitosterol and the carotenoids lutein and zeaxanthin were identified as components of the active hexane extract, which also exhibited a growth suppressing effect against two human breast cancer cell lines MCF-7 and BT-20. (C) 1998 Elsevier Science Ireland Ltd.