Impact of palm oil mill effluent on the activities of some antioxidative parameters in maize plant (Zea mays L.)

This study was carried out to evaluate the effect of palm oil mill effluent (POME) on some antioxidative parameters in maize plant. Fresh POME was used to pollute the soil at concentrations of 10%, 20% and 30% (w/w). Analysis of the maize plants after two, three and four weeks of planting showed alterations in the activities of the antioxidative enzymes measured. There was significant increase (p< 0.05) in catalase and peroxidase activities for plants grown in 20% and 30% POME-treated soils for 2, 3 and 4 weeks after planting. Significant increase in malondialdehyde (MDA) levels was observed in the fourth week for maize grown in 20% and 30% POMEtreated soil. Increase in the level of these enzymes and in MDA levels suggests that, palm oil mill effluent induces oxidative stress in the maize plant and may be deleterious to the growth of the maize plant.Keywords: palm oil mill effluent, maize, catalase, peroxidase, malondialdehyd

Comparative Study of Phenolic Content and Antioxidant Activity of Leaf Extracts of Alstonia boonei and Eupatorium odoratum

This study investigated the in vitro antioxidant activity and phenolic content of aqueous and ethanol extracts of Alstonia boonei and Eupatorium odoratum leaves. Total phenol, flavonoid and flavonol content of the extracts were estimated to determine the levels of phenolics in the extracts. The antioxidant capacity of the extracts were assessed through diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and reducing power (RP). The results revealed that the DPPH radical scavenging ability of aqueous extract of E. odoratum (with IC50 = 0.07± 0.003mg/ml) compares favourably with that of the standard ascorbic acid (IC50 = 0.06 ± 0.01 mg/ml). There was a dose-dependent increase in FRAP and RP capacity in all the extracts. The ethanol extract of E. odoratum had the highest FRAP while the aqueous extract of A. boonei showed the highest RP ability when compared with the other extracts. However, flavonol content was highest in the aqueous extract of E. odoratum followed by ethanol extract of A. boonei. The phenolic and flavonoid contents of extracts of E. odoratum were higher than that of A. boonei extracts. This study, therefore, reveals that aqueous extract of A. boonei and ethanol extract of E. odoratum leaf are more effective free radical scavengers and antioxidants relative to the other extract forms. These findings support the use of these extracts as potential sources of natural antioxidants.Keywords: Alstonia boonei, Eupatorium odoratum, phenolics, antioxidant