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

Physicochemical changes in maize plant (Zea mays) grown on contaminated soil exposed to sawdust treatment

The potential effects of sawdust for bioremediation of growing maize grown on crude oil contaminated soil was evaluated in this study. The experiment was divided into 3 groups control (soil without crude oil), polluted (soil with varying concentrations of crude oil), and sawdust treated (polluted soil with 50g sawdusts). The polluted and sawdust treated regime received four levels of treatments with crude oil (25g, 50g, 75g and 100g). Viable seeds of maize were grown on the soil beds for 35 days to assess the % germination, % survival, stem height, chlorophyll a and b, oxidative stress indicators and selected macronutrients using standard methods. Data obtained shows that the growth performance of the sawdust treated samples containing low concentration of crude oil was better in comparison to polluted groups but less than that of control. Sawdust remediation helped in overcoming the growth inhibition due to pollution to some extent. Significant increase (p<0.001) in the activity of antioxidant enzymes (superoxide dismutase, catalase and peroxidase) were observed in the sawdust treated regime when compared with the polluted and control groups. The result also showed a significant decrease (p<0.001) in Malondialdehyde levels and a non- significant increase (p>0.05) in macronutrients assessed in the remediated regime when compared with the polluted regime. Remediation of the polluted soil with sawdust relieved the inhibitory effect of crude oil on the plant growth particularly in groups containing lower concentrations of crude oil.Keywords: crude oil, sawdust, antioxidants, oxidative stres

Portfolio optimization and index tracking for the shipping stock and freight markets using evolutionary algorithms

This paper reproduces the performance of an international market capitalization shipping stock index and two physical shipping indexes by investing only in US stock portfolios. The index-tracking problem is addressed using the differential evolution algorithm and the genetic algorithm. Portfolios are constructed by a subset of stocks picked from the shipping or the Dow Jones Composite Average indexes. To test the performance of the heuristics, three different trading scenarios are examined: annually, quarterly and monthly rebalancing, accounting for transaction costs where necessary. Competing portfolios are also assessed through predictive ability tests. Overall, the proposed investment strategies carry less risk compared to the tracked benchmark indexes while providing investors the opportunity to efficiently replic ate the performance of both the stock and physical shipping indexes in the most cost-effective way