Phytochemical composition and antiproliferative activities of bran fraction of ten Maryland-grown soft winter wheat cultivars: Comparison of different radical scavenging assays

Phytochemicals (ferulic acid, tocopherols, and carotenoids) composition and antiproliferative activities of bran samples of the 10 soft winter wheat varieties grown in Maryland were investigated. All extracts were assayed for total phenolic content and free radical scavenging capacities by multiple colorimetric assays along with cellular antioxidant activity (CAA) and antiproliferative activity. Ferulic acid was the predominant phenolic acid in all 10 wheat bran samples with concentration ranging between 1.1 and 1.7 mg/g. The concentrations of lutein, zeaxanthin, and β-carotene ranged between 1.0–1.4, 0.2–0.3, and 0.1–0.2 μg/g, respectively. Significant amount of α-tocopherol (2.3–5.3 μg/g) was quantified in all bran samples along with minor quantity of δ-tocopherol (∼0.1 μg/g). No significant correlation between ferulic acid, tocopherol and carotenoid content and in vitro antioxidant radical scavenging assays or total phenolic content was observed. The Jamestown wheat bran demonstrated significant antiproliferative activities against both HT-29 and Caco-2 colon cancer cells at concentration of 50 mg bran equivalent (BE)/mL.