Effects of Plum Fruits Extracts at Different Growth Stages on Quinone Reductase Induction and Growth Inhibition on Cancer Cells

The plum (Prunus salicina L., cv. ‘Soldam’) fruits were harvested at different growth stages, and then extracted using 80% methanol, respectively. The methanol extracts of plum were investigated for their growth inhibition on 6 kinds of human cancer cells using MTT assay and for their activity to induce quinone reductase (QR) in murine Hepa1c1c7 cells. Among various methanol extracts of plum, the plum 1~4 (immature fruit), which thin out 10~25 days before final harvest, showed higher anticarcinogenic activity against 5 kinds of cancer cells than plum 5~9 (intermediate-mature and mature fruit). Especially, plum 1 and 2 were exhibited the strongest growth inhibiting activities to AGS, HepG2 and MDA cancer cells. Also the plum extracts induced the activity of QR, an anticarcinogenic marker enzyme, in Hepa1c1c7 cells while the induction of QR activities by adding plum extracts were shown to be a little difference depending on growth stages. These results suggested that methanol extracts of immature plum can be considered as an effective natural cancer chemoprevention materials.