Phenolic compounds are associated with cell walls in cereals and legumes. Phenolic composition and bioactive properties of cell walls and whole grain of sorghum, teff and cowpea were determined. Whole grain extracts had higher total phenolic content (630–2,782 mg CE/g) and total flavonoid content (0.033–0.17 mg CE/g) than cell wall extracts (261–1,005 and 0.011–0.047 mg CE/g, respectively). Similar trends were observed for 2,2'-azinobis (3-ethyl-benzothiazoline-6 sulfonic acid) radical scavenging (whole grain: 30–87; cell wall: 22 μM TE/g), oxygen radical absorbance capacity (whole grain: 47–964; cell wall: 40–183 μM TE/g) and ferric reducing power (whole grain: 85–279; cell wall: 41–95 mg vitamin C equivalent/g). Whole grains contained both phenolic acids and flavonoids. Ferulic acid was a major component of cell walls. Whole grain and cell wall extracts inhibited low-density lipoprotein oxidation and protected against oxidative DNA damage. Cereal and legume cell walls may be considered important potential contributors to human health because of their phenolic composition.
Phenolic compounds in cereals and legumes are important components of dietary fiber in which they occur mainly in association with cell wall components. There is increasing research focus on phenolic compounds due to their bioactive properties and potential health benefits. Investigation of the cell wall-bound phenolic compounds is necessary to establish their potential contribution to human health. In this study, the phenolic composition and antioxidant activities of extracts from cell wall preparations and whole grain of selected cereals and legumes of importance in Africa, as well as their protective effect on oxidized DNA damage and copper catalyzed low-density lipoprotein oxidation, were determined. This research provides insight into the potential health benefits offered by the grains studied, such as prevention of chronic diseases of lifestyle and the importance of the bioactive phenolic constituents of cell walls in this regard.