Abstract

Bioactive compounds were extracted from 6 wild and 4 domesticated cereal grains of Zimbabwe, using 50% methanol with the aim of testing their capability to prevent phospholipid peroxidation and β-carotene bleaching. The highest yield of phenolic compounds was obtained from Eleusine indica (a wild cereal) with 7.16 mg GA/100 mg sample, while the least yield was obtained from Amaranthus hybridus with 1.13 mg GA/100 mg sample. Antioxidant activities of the cereal extracts were studied using the β-carotene-linoleic acid and the inhibition of phospholipid peroxidation assays. It was shown that Sorghum arundinaceum had the greatest (77%) increase in inhibition of phospholipid when its concentration was increased from 20 to 80 mg/ml, while Eleusine corocana, a domestic cereal grain had the least. Relative to a standard BHA (an artificial antioxidant), E. indica was found to have the highest ability (67%) to prevent bleaching of β-carotene, while Pennisetum spp with 17.3% inhibition, had the least ability. Owing to the ability of the cereal grain extracts to act as antioxidants, the studies can be further extended to exploit the phenolic extracts as replacements of artificial antioxidants like butylated hydroxyl anisole (BHA) in food and health supplements and nutraceuticals.

Key words: Wild cereal grains, antioxidants, phospholipid peroxidation, health supplements.