Methanol Extract of Peltophorum pterocarpum Stem Bark Has Antimalarial Activity and Normalizes Biochemical Changes Induced by Plasmodium berghei Infection

This study evaluated the antimalarial, haematological and biochemical status of Plasmodium berghei Anka 65-infected mice treated with methanol extract of Peltophorum pterocarpum stem bark (MEPT). The acute toxicity profile and phyto-constituents were also evaluated. Thirty mice were divided into 6 groups of 5 mice each. Group 1 served as normal control and received distilled water only. Group 2 was parasitized and untreated. Groups 3-5 were parasitized and treated with 200, 400 and 600 mg/kg b.w. body weight of MEPT respectively. Group 6 was parasitized and treated with 28 mg/kg. b.w. of arthemeter/lumenfantrin combination. Malaria parasitemia were monitored on treatment days 0-3. Antioxidant, liver, kidney and lipid peroxidation status were determined using classical methods 5 days post-treatment. There were dose-dependent reductions in malaria parasitemia percentages of groups 3-5 that are comparable with group 6. In addition, there were dose and duration-dependent increases in malaria chemo-suppression in groups 3-5. The existence of oxidative stress, lipid peroxidation, and kidney and liver dysfunctions were observed in group 2 when compared with group 1. Treatment of groups 3-5 with MEPT and group 6 with arthemeter/lumenfantrin for 4 days restored the biochemical anomalies induced by malaria. The extract was tolerable up to 5,000 mg/kg b.w. of MEPT. The presence of flavonoids, alkaloids, saponins, tannins, steroids, carotenoids, glycosides, anthraquinones, terpenoids and anthocyanins were detected in high amounts while phenols was detected in low amount in MEPT. These suggest that MEPT possesses antimalarial activity and normalizes malaria-modified biochemical changes. These effects might be attributed to its bioactive constituents. Keywords: malaria, Peltophorum pterocarpum, phytochemicals, toxicity, biochemical dysfunctions DOI: 10.7176/ALST/73-05 Publication date: April 30th 201

Impacts of some divalent cations on periplasmic nitrate reductase and dehydrogenase enzymes of Escherichia, Pseudomonas and Acinetobacter species

The impacts of Hg2+, Cd2+ and Zn2+ on the activities of periplasmic nitrate reductase (NAP) and dehydrogenase (DHA) enzymes of three organisms isolated from soil and sediment-water interface were analysed in liquid culture studies. NAP and DHA activities were estimated from nitrite and triphenyl formazan were produced respectively after 4h incubation at 28 ± 2oC. Hg2+ completely inhibited NAP activity in Escherichia and Pseudomonas spp at all the concentrations (0.2 – 1mM) while progressive inhibitions of NAP activity were observed in Escherichia and Pseudomonas spp with increasing concentrations of Zn2+ and Cd2+. Both metals were stimulatory to NAP of Acinetobacter sp at 0.2 – 1mM. Apart from stimulation of DHA activity by Zn2+ (0.2 – 1mM) in Escherichia sp, Cd2+ (0.4 -1.0mM) in Acinetobacter sp and (1.0mM) in Pseudomonas sp, all the metals progressively inhibited DHA activities in the three organisms. In Escherichia sp, the activities of the two enzymes were negatively correlated on exposure to Zn2+ (r = -0.91) and positively correlated (r = >0.90) on exposure to Cd2+ and Hg2+. Based on IC50 values of the metals for the DHA and NAP enzymes, the most resistant of the three organisms were Escherichia sp and Acinetobacter sp respectively. Quantitatively, NAP with its lower IC50 values than DHA was a more sensitive toxicity measure for Hg2+ in all the organisms. The sensitivity of microbial metabolic enzymes to the toxic effects of metals varies with the type of enzyme, metal and the microorganism involved