Antiproliferation Properties of Grain Sorghum Dry Distiller’s Grain Lipids in Caco-2 Cells

Abstract

Antiproliferative properties of lipids extracted from grain sorghum (GS) dry distiller's grain (DDG) were analyzed to determine the feasibility of developing GS coproducts as a source for human health dietary ingredients. The lipid extract of GS-DDG was delivered to human colon carcinoma (Caco-2) cells by solubilizing 0-1000 microg/mL of GS-DDG lipids in 100 microg/mL increments with micelles. A significant reduction in cell viability (25-50%) resulted at treatment levels of 400-1000 microg/mL GS-DDG lipids (p < 0.05). Alternatively, total protein levels of cells treated with 400, 500, and 600 microg/mL of GS-DDG lipid were not significantly different from the control, indicating cell growth during the treatment period. Total cell counts for the control were not significantly different from the GS-DDG lipid treated cells, but dead cell counts increased by approximately 10% for the latter sample with a concomitant increase of the intercellular protein lactate dehydrogenase leakage (30-40%) in the medium. Preliminary analysis by the fluorescence-activated cell method (FACs) demonstrated that nonviable cells were in either the early apoptotic, late apoptotic, or necrotic stage post-treatment with 400, 500, and 600 microg/mL GS-DDG lipids. Physiochemical characterization of the GS-DDG lipids used for the antiproliferation study showed the presence of vitamin E (predominantly gamma-tocopherol), triacylglycerides (predominantly linoleic acid), policosanols, aldehydes, and sterols (predominantly campesterol and stigmasterol), each of which or as synergistic/additive group of constituents may be responsible for the antiproliferative effect.