Effects of Methanolic and Hexane-Derived Dwarf Mistletoe (Arceuthobium) Extracts on the Viability of Salmon Cells in Culture: Do These Extracts Induce Necrosis and/or Apoptosis?

Abstract

With DMT showing promise as a source of biosurfactants and/or antimicrobials, we wished to assess the effects DMT extracts on eukaryotic cells, particularly with respect to necrosis (toxic cell death) and apoptosis (programmed cell death). We prepared a crude methanolic extract from the DMT (A. americanum) as well as extracts from 9:1 methanol:water (polar) and hexanes (non-polar) fractions derived from the crude. We then used four 10-fold serially-diluted concentrations of these extracts (28.6 through 0.00286 mg/mL) to challenge salmon embryo (CHSE₂₁₄) cells in culture. Following a 30-minute incubation period, we used a Sigma® Apoptosis Detection Kit coupled with statistical analysis to assess the percentage difference of necrotic and apoptotic cells relative to the control for the three extracts tested at each of the five concentrations. We found that the crude methanolic extract inhibited apoptosis at lower concentrations, but triggered both necrosis and apoptosis at higher. The 9:1 fraction also inhibited apoptosis at the intermediate concentration tested, and did not cause apoptosis in any concentration tested, although the higher concentrations did apparently trigger necrosis. Conversely, the hexane fractions induced both necrosis and apoptosis in the salmon cells. The 9:1 raction appears to have little cytotoxic effects, whereas the extract derived from the hexanes fraction shows potential for development as an anti-cancer agent, since compounds that trigger necrosis and apoptosis have been used for this purpose.

Key Words: apoptosis, biosurfactants, cancer, cytotoxicity, fractionation, necrosis.