ABSTRACT
Oxidative stress has been implicated in many illnesses affecting humans including cardiovascular diseases and cancer. Antioxidants can prevent the damage to cells caused by free radicals. This study was carried out in order to compare the phytochemical constituents and antioxidant activity of the ethanol and n-hexane extracts of Eleusine coracana seeds. Powdered Eleusine coracana seeds were extracted by maceration method using ethanol and n-hexane for seven days respectively. The extracts were then investigated for phytochemical constituents using simple phytochemical screening methods as well as gas chromatography mass spectrometry (GC-MS). The flavonoid and total phenol content of each extract was determined using Folin-Ciocalteu’s method and Aluminium chloride test respectively. The free radical scavenging activity of the extracts were investigated using 1,1 diphenyl,2 picryl hydrazyl (DPPH) free radical scavenging method. The percentage yield of the ethanol extract was 0.30% while that of the n- hexane extract was 0.05%. The secondary metabolites identified in the ethanol fraction were were Carbohydrates, Flavonoids, Tannins, Alkaloids, saponins, proteins, steroids and deoxysugars while those identified in the n- hexane extract were Carbohydrates, saponins, steroids and deoxysugars while those identified in the n- hexane extract were Carbohydrates, Flavonoids, Tannins, Alkaloids, saponins, steroids and deoxysugars while those identified in the n- hexane extract were Carbohydrates, saponins, steroids and deoxysugars. The total phenol content (TPC) of the ethanol extract was 33.85±0.08 mg GAE/ g and the total flavonoid content (TFC) were found to be 77.80 ± 0.02 mg QE/g. The n-hexane extract gave 49.5 ± 0.005 mg QE/g (TFC) and 3.24 ± 0.03 mg GAE/ g (TPC). The IC50µg/ml for the n-hexane extract was >1000 µg/ml and that of ethanol was 19.83 µg/ml as compared to the Ascorbic acid which had an IC50 of 3.09 µg/ml. The study revealed that the secondary metabolites identified in both extracts were oleic acid, nhexadecenoic acid, cis13-octadecenoic acid, trans-13-octadecenoic acid, squalene, gammatocopherol, gammasistosterol, stigmasterol. The n-hexane extract of Eleusine coracana seeds have little or no xi antioxidant activity while the ethanol extract has greater antioxidant activity. The major compounds identified by GCMS in both extracts were oleic acid with the n-hexane fraction having greater percent of the oleic acid. The ethanol extract is a better solvent for the extraction of phytochemical components with high antioxidant activity from Eleusine coracana seeds than nhexane.
