Sodium metabisulphite induced polymerization of sickle cell haemoglobin incubated in extracts of three medicinal plants (Anacardium occidentale, Psidium guajava and Terminalia catappa)

The present in vitro study ascertained the capacity of three medicinal plants, namely, Anacardium occidentale, Psidium guajava and Terminalia catappa, to alter polymerization of sickle cell haemoglobin (HbS). Spectrophotometric method was used to monitor the level of polymerization of haemolysate HbS molecules treated with sodium metabisulphite (Na2S2O5) at a regular interval of 30 s for a period of 180 s in the presence of separate aqueous extracts of A. occidentale, P. guajava and T. catappa. At time intervals of 30 s, the level of polymerization was expressed as percentage of absorbance relative to the control sample at the 180th s. Although, extracts of the three medicinal plants caused significant (p < 0.05) reduction in polymerization of deoxyHbS molecules, the corresponding capacity in this regard diminished with increase in incubation time. Aqueous extract of P. guajava exhibited the highest capacity to reduced polymerization of deoxyHbS molecules. Whereas at t > 60 s, extract concentration of 400 mg% of A. occidentale activated polymerization of deoxyHbS molecules by 6.23 ± 1.34, 14.53 ± 1.67, 21.15 ± 1.89 and 24.42 ± 1.09%, 800 mg% of T. catappa at t > 30 s gave values of 2.50 ± 1.93, 5.09 ± 1.96, 10.00 ± 0.99, 15.38 ± 1.33 and 17.31 ± 0.97%. Therefore, the capacity of the three medicinal plants to interfere with polymerization of deoxyHbS molecules depended on duration of incubation and concentration of the extracts.Key words: Polymerization, deoxyHbS, Anacardium occidentale, Psidium guajava, Terminalia catappa

Thermal and pH stabilities of partially purified polyphenol oxidase extracted from Solanum melongenas and Musa sapientum fruits

Enzyme activity depends largely on environmental conditions such as temperature and pH. The stability of polyphenol oxidase (PPO) extracted from Solanum melongenas and Musa sapientum fruits preincubated in varying thermal and pH conditions were carried out. Enzyme activity was measured by spectrophotometric methods. The reaction mixture contained 3.5 mL of 0.20 M phosphate buffer (pH = 6.8), 1.0 mL of 0.75 mM catechol, and 0.5 mL of enzyme solution. PPOS. melongenas and PPOM. sapientum gave different temperature and pH optima. The temperature-activity profile of PPOS. melongenas and PPOM. sapientum showed a strong positive correlation (r = 0.907363). At pH = 10.0, PPOM. sapientum activity represented 65.3% decay in enzyme activity, whereas PPOS. melongenas represented 79.3% decay in enzyme activity. PPOS.melongenas and PPOM. sapientum stability at pre-incubated temperatures of 20, 50 and 60°C and pH values of 3.5, 6.0 and 8.0 were measured. Residual activities of PPOS.melongenas and PPOM. sapientum showed a strong positive correlations under the same experimental thermal conditions, with exception at 20°C (r = 0.693375). Specifically, pre-incubation of PPOM.sapientum for t = 90 min at 60°C caused 18.4% decay in relative activity of PPOM. sapientum. At t = 90 min, pre-incubation of PPOM. sapientum, at pH = 3.5 caused decay in activity within the range of 30.8-36.1%, whereas PPOM. sapientum pre-incubated in pH = 6.0 and pH = 8.0 gave decay in activity within the range of (1.5-9.8%) and (2.7-6.5%) respectively. PPOS.melongenas and PPOM. sapientum showed relatively higher stabilities as the incubation pH tended towards alkaline conditions, whereas the two experimental temperatures (20 and 60°C) promoted destabilization.Keywords: Polyphenol oxidase, temperature, pH, Solanum melongenas and Musa sapientum.African Journal of Biotechnology Vol. 12(38), pp. 5688-569

A systematic review of experimental methods to manipulate secondary hyperalgesia in humans: protocol

Background Neuropathic pain affects 7–10% of people, but responds poorly to pharmacotherapy, indicating a need for better treatments. Mechanistic research on neuropathic pain frequently uses human surrogate models of the secondary hyperalgesia that is a common feature of neuropathic pain. Experimentally induced secondary hyperalgesia has been manipulated with pharmacological and non-pharmacological methods to clarify the relative contributions of different mechanisms to secondary hyperalgesia. However, this literature has not been systematically synthesised. The aim of this systematic review is to identify, describe, and compare methods that have been used to manipulate experimentally induced secondary hyperalgesia in healthy humans. Methods A systematic search strategy will be supplemented by reference list checks and direct contact with identified laboratories to maximise the identification of data reporting the experimental manipulation of experimentally induced secondary hyperalgesia in healthy humans. Duplicated screening, risk of bias assessment, and data extraction procedures will be used. Authors will be asked to provide data as necessary. Data will be pooled and meta-analyses conducted where possible, with subgrouping according to manipulation method. Manipulation methods will be ranked for potency and risk. Discussion The results of this review will provide a useful reference for researchers interested in using experimental methods to manipulate secondary hyperalgesia in humans and will help to clarify the relative contributions of different mechanisms to secondary hyperalgesia

Extraction and Activity of Polyphenol Oxidase from Kolanuts (Cola nitida and Cola acuminata) and Cocoa (Theobroma cacao)

The activity of polyphenol oxidase was investigated in kolanuts (Cola nitida and Cola acuminata) as well as cocoa (Theobroma cacao). Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). The maximum enzyme activity (Vmax) for the three plant species were 1.1 x10-3 O.D/Sec, 1.5 x 10-4 O.D/Sec and 2.5 x 10-3 O.D/Sec for C. nitida, C. acuminata and T. Cacao respectively. The Michealis – Menten's constant (Km) were 9.1x10-4M, 9.1x10-4M and 5.0x10-3M for C.nitida, C.acuminata and T.cacao respectively. The variation in maximum enzyme activity (Vmax) reflects interspecies differences in the absolute quantity of enzyme present in the three plant tissues. However, the km values were the same for the two species of kolanuts but varied when compared with the km value of enzyme extract of T. Cacao. The differences in km and Vmax values showed that there are variations in the physicochemical characteristics and absolute quantity of polyphenol oxidase present in the three plant species. Journal of Agriculture and Food Sciences Vol. 4 (2) 2006: pp. 115-12

Effect of cinnamic acid on polyphenoloxidase activity of dioscorea rotundata

No Abstract.Global Journal of Pure and Applied Sciences Vol. 13 (3) 2007: pp.387-38

Studies on the anti-sickling effects of Azadirachta indica and Vernonia amygdalina on Hbss erythrocytes

The percentage of hemoglobin S polymerization in the presence of ethanol extracts of Azadirachta indica and Vernonia amygdalina were used as the basis for ascertaining the possible anti-sickling properties of the two plant species on HbSS erythrocytes. In vitro HbS polymerization was induced by 2% sodium metabisulphite solution and comparative studies were carried out to evaluate the relative levels of HbS polymerization of the control sample with those of the two test samples, TS 1 (ethanol extract of A. indica) and TS 2 (ethanol extract of V. amygdalina). Spectrophotometric method was used to monitor the level of gelation of HbS for a period of twenty-two (22) minutes (l max = 700nm). The results showed that ethanol extracts of V. amygdalina activated HbS polymerization between 70.32% and 0.32% while A. indica inhibited HbS polymerization within the range of 37.28% and 1.83%. These findings suggest that A. indica has medicinal potentials for the management of sickle cell anemia disease. International Journal of Natural and Applied Sciences Vol. 2(1) 2006: 24-2

Effect of phenacetin on nand-mathemoglobin reductase of human Erythrocytes

No Abstract. Global Journal of Pure and Applied Sciences Vol. 12(3) 2006: 339-34

Effect of ethanolic extracts of Garcina kola, Cola nitida and Cola acuminata on in vitro hemoglobin s polymerization

No Abstract.International Journal of Tropical Agriculture and Food Systems Vol. 1 (3) 2007: pp. 220-22

Effect of experimental quinine administration on plasma levels of hemoglobin and methemoglobin in guinea pig

In vivo studies were carried out to ascertain the effect of increasing dose of quinine on plasma levels of hemoglobin and methemoglobin in guinea pigs. Increasing dose of quinine in the order of 0.02 g/kg, 0.03 g/kg, 0.04 g/kg, 0.05 g/kg 0.06 g/kg, 0.07 g/kg, 0.08 g/kg, 0.10 g/kg and 0.12 g/kg were introduced into the peritoneal cavity of the designated nine sets of test animals. The doses were administered for 48 hours at a regular interval of 6 hours. Six hours after the last dose administration, blood samples were withdrawn for the determination of plasma levels of hemoglobin and methemoglobin. Plasma hemoglobin concentration increased from 11.55 +0.32 g/100ml to a critical value of 14.30 g/100ml from the control to 0.08 g/kg dose administration. A further increase in the dose of quinine beyond 0.08 g/kg engendered a rapid decrease of plasma hemoglobin concentrations. Plasma methemoglobin levels exhibited a biphasic characteristic with peak value of 2.52 + 0.20% at 0.07 g/kg dose administration followed by decrease when doses of quinine were further increased. It appeared that at a relatively low dose quinine was moderately haematinic while exhibiting low propensity to elicit increased plasma levels of methemoglobin. International Journal of Natural and Applied Sciences Vol. 1(2) 2005: 150-15