Inhibition of Cellular Mediated LDL Oxidation by Select Sorghum Brans

Abstract

Certain sorghum brans contain significant levels of phenolic compounds. Sumac and shanqui varieties are enriched with proanthocyanidins while black sorghum contains high levels of anthocyanins. We examined the effect of extracts (10% w/v in 50% ethanol) of six sorghum brans on the oxidation of LDL (100 µg protein/ml) mediated by J774 macrophages in Ham's F‐10 culture medium for 18 hr. When the extracts were presented to macrophage cultures at a concentration of 0.05% (v/v), three varieties significantly inhibited oxidation of LDL (sumac > shanqui > black) as measured by TBARS formation. Three other varieties (fontanelle, mycogen and white) were rather low in phenolic content and did not produce significant inhibition. When the extract of sumac sorghum was set at 0.02 % (v/v), LDL oxidation was inhibited by approximately 50%. The greater inhibitory effect of sumac and shanqui sorghum brans on LDL oxidation when compared to black sorghum bran may be a result of the capacity of these select sorghum brans to precipitate LDL, rendering it unavailable for oxidation. Ethanolic extracts of wheat, rice and oat brans did not inhibit the oxidation of LDL. These results demonstrate that phenolic compounds in select sorghum brans can significantly inhibit cellular oxidation of LDL (Supported by grant #5854304363 from the USDA)