Oregon's forestry outlook: an uncertain future

The theme for the 1989 Starker Lectures concerned uncertainty surrounding forests and forestry in Oregon and the Pacific Northwest. It was a timely theme. Indeed, the uncertainties concerning trade-offs among commodity production and environment and the allocation of forest land, especially public lands, loom large as we enter the decade of the 90's. We invited for the 1989 lectures speakers who would address current issues not in the value-laden terms of the day, but in a more detached and analytical way, an approach that better permits the listener or reader to make judgements based on factual and scientific information. This, we believe, is a proper role for the College of Forestry

Cytotoxicity of Polyphenolic/Flavonoid Compounds in a Leukemia Cell Culture

Flavonoidne sastavnice propolisa biološki su aktivne tvari koje posjeduju antioksidativna, protutumorska, imunomodulacijska i protuupalna svojstva. Istražili smo citotoksično djelovanje polifenolnih spojeva (kvercetina, kavene kiseline, krizina, naringenina i naringina) na različite linije leukemijskih stanica (MOLT, JURKAT, HL-60, RAJI, U937). Stanice su inkubirane u mediju RPMI-1640 obogaćenom 10 %-tnim fetalnim telećim serumom, pri temperaturi od 37 °C u atmosferi s 5 % CO2, uz dodatak polifenolnih/flavonoidnih spojeva različitih koncentracija (100 µg mL-1, 50 µg mL-1, 25 µg mL-1 i/ili 12,5 µg mL-1). Utvr|eno je da citotoksičnost flavonoida ovisi o vrsti i koncentraciji; najjači citotoksični učinak imaju kvercetin te krizin i kavena kiselina. Krizin i/ili naringenin primijenjeni na U937 i HL-60-stanice stimuliraju proliferaciju stanica, {to upućuje na bifazni učinak istraživanih spojeva na monocitne leukemijske stanice. Dobiveni rezultati upućuju na potrebu daljnjih istraživanja učinkovitosti flavonoida na molekularnoj razini.Flavonoid components of propolis are biologically active substances with antioxidative, immunostimulative, immunomodulative, and anti-inflamatory properties. The aim of the study was to investigate their cytotoxic effect on different leukaemia cell lines. For this purpose we used five different flavonoids (quercetin, caffeic acid, chrysin, naringenin, and naringin) and five types of leukemia cell lines (MOLT, JURKAT, HL-60, RAJI and U937). Cells were cultured at 37 °C in the RPMI-1640 medium supplemented with 10 % FCS in humified atmosphere with 5 % of CO2. Flavonoids were added in the following concentrations: 100 µg mL-1, 50 µg mL-1, 25 µg mL-1, or 12.5 µg mL-1. The results show different dose- and cell-type-dependent cytotoxicity. Among the flavonoids, quercetin showed the strongest cytotoxic effect in all cell lines. Caffeic acid and chrisyn also expressed a high level of cytotoxicty. Treatment of U937 and HL-60 cell lines with low concentrations of chrisyn or naringenin stimulated cell proliferation. These results suggest a biphase effect of the tested compounds on monocyte cell lines. Cytotoxicity and growth stimulation mechanisms caused directly by flavonoids should further be investigated on the molecular level