Browsing by Author "Igunnu, Adedoyin"
Now showing 1 - 20 of 22
Results Per Page
Sort Options
Item Activation of Rat Intestinal Alkaline Phosphatase by Taurine May be an Alternative Mechanism of Endotoxemic Injury Protection(Faculty of Science, Usman Danfodiyo University, Sokoto, 2015-06) Arise, R.O.; Igunnu, Adedoyin; Olajunyin, A.; Akiode, O.S.; Olatomiwa, O.J.Investigation of the effect of taurine on the hydrolysis of para-nitrophenylphosphate (p-NPP) by rat intestinal alkaline phosphatase (ALP), L-phenylalanine inhibition of ALP and the mechanism of ALP activation by taurine as well as its role in endotoxemic injury protection was carried out. Rat intestinal ALP was exposed to taurine, and L-phenylalanine at varying concentrations and periods of time. Substrate concentration-dependent kinetic analysis was carried out at 10 mM concentration of taurine and 5.17mM of p-NPP. The concentration dependent kinetic analysis of L-phenylalanine was also investigated at 60 mM. The partially purified rat intestinal alkaline phosphatase activity was also investigated in the presence of taurine. Their interactive effect on L-phenylalanine inhibition was also analyzed. Investigation of the effect of taurine on rat intestinal ALP hydrolysis of p-NPP revealed that taurine is an activator of intestinal ALP. At 10 mM taurine and 60 mM L-phenylalanine, taurine relieved Lphenylalanine inhibition of rat intestinal ALP. The effect of lipopolysaccharide in the absence and presence of taurine on ALP activity was also carried out in vivo. The kinetic analysis of the data from the in vivo study revealed that rat intestinal ALP activity is higher (12x10-3nmol-1min-1mg protein) in the presence of taurine and LPS when compared with the activity in the presence of LPS (9x10-3nmol-1min-1mg protein) or taurine (8.8x10-3nmol-1min-1mg protein) alone. From this study, it may be concluded that the activation of rat intestinal ALP by taurine may be one of the mechanisms of endotoxemic injury protection.Item Activatory Effects of Manganese and Cobalt Ions on the Activity of Cellulase Produced by Aspergillus niger(Nigeria Society of Biochemistry and Molecular Biology, 2013) Igunnu, Adedoyin; Malomo, S.O.; Saliu, B.K.Cellulase is an enzyme with wide industrial applications, however the optimization of its activity by metal ions has not been fully characterised. In this study, the effect of interaction of Mn2+ and Co2+ on the activity of cellulase produced by Aspergillus niger using submerged fermentation process was investigated. Cellulase activity was determined by measuring the concentration of glucose produced from the hydrolysis of carboxymethylcellulose (CMC) catalysed by the enzyme. Both Mn2+ and Co2+ (0.2-10 mM) activated cellulase-catalysed hydrolysis of CMC with optimal concentrations at 8 mM and 1 mM respectively. Synergistic interaction between Mn2+ and Co2+ promoted hydrolysis of CMC by cellulase with optimal activation at 8 mM Mn2+ and 1 mM Co2+. This study revealed that the activity of cellulase produced by Aspergillus niger can be optimized in the presence of optimal concentrations of Mn2+ and Co2+ for its various applications.Item Activatory Effects of Manganese and Cobalt Ions on the Activity of Cellulase Produced by Aspergillus niger(Nigerian Society for Biochemistry and Molecular Biology, 2013) Igunnu, Adedoyin; Saliu, Bolanle Kudirat; Malomo, Sylvia O.Cellulase is an enzyme with wide industrial applications, however the optimization of its activity by metal ions has not been fully characterised. In this study, the effect of interaction of Mn2+ and Co2+ on the activity of cellulase produced by Aspergillus niger using submerged fermentation process was investigated. Cellulase activity was determined by measuring the concentration of glucose produced from the hydrolysis of carboxymethylcellulose (CMC) catalysed by the enzyme. Both Mn2+ and Co2+ (0.2-10 mM) activated cellulase-catalysed hydrolysis of CMC with optimal concentrations at 8 mM and 1 mM respectively. Synergistic interaction between Mn2+ and Co2+ promoted hydrolysis of CMC by cellulase with optimal activation at 8 mM Mn2+ and 1 mM Co2+. This study revealed that the activity of cellulase produced by Aspergillus niger can be optimized in the presence of optimal concentrations of Mn2+ and Co2+ for its various applications.Item Anti-diabetic Activity of Aqueous Extract of Senna alata (Fabacea) Flower in Alloxan-induced Diabetic Male Rats(Published by Cameroon Biosciences Society, 2016) Yakubu, M.T.; Uwazie, N.J.; Igunnu, AdedoyinThis study investigated the acclaimed anti-diabetic potential of aqueous extract of Senna alata flower in alloxan-induced diabetic rats. Forty-two, male Wistar rats were randomized into six groups (I-VI) such that animals in group I which were non-diabetic received 0.5ml each of distilled water while those in groups II-IV which were induced into diabetes (intraperitoneal administration of 150 mg/kg body weight of alloxan) received orally 0.5ml each of distilled water, glibenclamide (2.5 mg/kg body weight), 25, 50 and 75mg/kg body weight of the extract respectively once daily for 13 days. The secondary metabolites in decreasing order of abundance were phenolics, flavonoids, cardiac glycosides, steroids, saponins, anthraquinones, tannins and alkaloids. The elevated (P < 0.05) blood glucose level, total cholesterol, triglycerides, low density lipoprotein-cholesterol, haemoglobin, total bilirubin, serum urea and creatinine as well as the reduced body weight, high density lipoprotein-cholesterol, liver glycogen, packed cell volume, albumin, conjugated bilirubin and hexokinase activity by the alloxan were reversed and or/ameliorated by the extract, similar to the reference drug, glibenclamide. The extract restored the alloxan treatment related distortion and atrophy in the pancreas. The available data in the study suggests that aqueous extract of Sena alata flower at the doses of 25, 50 and 75mg/kg body exhibited anti-diabetic activity with the highest dose displaying the most profound activity. The anti-diabetic activity conferred by the secondary metabolite is suggested, among other, to be via enhancing the activity of hexokinase. This study has justified the folkloric use of S. alata flower in the management of diabetes.Item Anti-inflammatory and bronchodilatory constituents of leaf extracts of Anacardium occidentale L. in animal models(Elsevier Limited, Oxford, UK, for Shanghai Association of Integrative Medicine and Shanghai Changhai Hospital, China., 2017) Awakan, J.O.; Malomo, S.O.; Adejare, A.A.; Igunnu, Adedoyin; Atolani, O.; Adebayo, A.H.; Owoyele, B.V.Objective: Anacardium occidentale L. leaf is useful in the treatment of inflammation and asthma, but the bioactive constituents responsible for these activities have not been characterized. Therefore, this study was aimed at identifying the bioactive constituent(s) of A. occidentale ethanolic leaf extract (AOEL) and its solvent-soluble portions, and evaluating their effects on histamine-induced paw edema and bronchoconstriction. Methods: The bronchodilatory effect was determined by measuring the percentage protection provided by plant extracts in the histamine-induced bronchoconstriction model in guinea pigs. The antiinflammatory effect of the extracts on histamine-induced paw edema in rats was determined by measuring the increase in paw diameter, after which the percent edema inhibition was calculated. The extracts were analyzed using gas chromatography-mass spectrometry to identify the bioactive constituents. Column chromatography and Fourier transform infrared spectroscopy were used respectively to isolate and characterize the constituents. The bronchodilatory and anti-inflammatory activities of the isolated bioactive constituent were evaluated. Results: Histamine induced bronchoconstriction in the guinea pigs and edema in the rat paw. AOEL, hexane-soluble portion of AOEL, ethyl acetate-soluble portion of AOEL, and chloroform-soluble portion of AOEL significantly increased bronchodilatory and anti-inflammatory activities (P < 0.05). Oleamide (9-octadecenamide) was identified as the most abundant compound in the extracts and was isolated. Oleamide significantly increased bronchodilatory and anti-inflammatory activities by 32.97% and 98.41%, respectively (P < 0.05). Conclusion: These results indicate that oleamide is one of the bioactive constituents responsible for the bronchodilatory and anti-inflammatory activity of A. occidentale leaf, and can therefore be employed in the management of bronchoconstriction and inflammation.Item Catalytic cofactors (Mg2+ and Zn2+ ions) influence the pattern of vanadate Inhibition of the monoesterase activity of calf intestinal alkaline phosphatase(Nigerian Society for Experimental Biology, 2014) Igunnu, Adedoyin; Arise, R.O.; Adebayo, J.O.; Olorunniji, F.J.; Malomo, S.O.The mechanism of modulation of vanadate inhibition of alkaline phosphatase activity by catalytic cofactors has not been fully characterized. We investigated the effect of the interaction of catalytic cofactors (Mg2+ and Zn2+) and vanadate (an active site inhibitor) on the rate of hydrolysis of para-nitrophenyl phosphate (pNPP) (monoesterase reaction) by calf intestinal alkaline phosphatase (CIAP). The results showed that vanadate significantly inhibited ʻcofactor-freeʼ CIAP, and the inhibition was relieved by the presence of the catalytic cofactors in the reaction. Our results show that the absence of the cofactors did not significantly alter the Km of the reaction, but caused a decrease in the Vmax. Kinetic analyses showed that vanadate inhibited CIAP-catalyzed hydrolysis of pNPP by decreasing the Vmax and increasing the Km of the reaction. The presence of cofactors in the reaction alleviated the effect of vanadate by increasing the Vmax and decreasing the Km. The activity of the dialyzed CIAP was increased by the addition of catalytic cofactors to vanadate-inhibited enzyme. This study provides preliminary data that reversible inhibition of CIAP is subject to the influence of catalytic cofactors. Further studies will reveal detailed mechanistic aspects of this observation and its significance in the biological system.Item Characterization of detergent-stable proteases isolated from Citrus sinensis fruit peel(Nigerian Society for Experimental Biology, 2017) Ibraheem, S.A.; Malomo, S.O.; Igunnu, AdedoyinProteases are important group of enzymes with wide industrial applications including laundry. They have been isolated and characterized from different agro wastes but the use of Citrus sinensis fruit peel as a source of protease has not been reported. In this study, low molecular weight (10-17 kDa) proteases were purified and characterized from C. sinensis fruit peel using a combination of ammonium sulphate precipitation, dialysis and sephadex G150 column chromatography. One unit of protease activity was defined as the amount of the enzyme required to liberate one microgramme (1 μg) of tyrosine from gelatin per minute at 37°C under standard assay conditions. The elution profile obtained from gel filtration chromatography depicted three peaks of protease activity designated as proteases I, II and III. The purification fold obtained for ammonium sulphate precipitation, dialysis and proteases I, II and III fractions were 1.7, 3.85, 9.47, 9.84 and 8.47 respectively. The activities of Proteases I and II were significantly increased (p<0.5) in the presence of 5-10 % w/v, and 1-10 v/v % Tween 80 respectively. However, the activity of Protease III was not significant affected (p>0.5) by Tween 80. Triton-X significantly increased (p<0.5) Protease II activity at 5 to 10% v/v concentrations but did not significantly affect (p>0.5) the activities of Proteases I and III between 1 to 10% v/v concentrations. SDS significantly increased (p<0.5) the activities of proteases I and II at 5-10 % w/v, and 1-10 w/v % respectively but did not significantly affect (p>0.5) Protease III activity. Findings from this study suggest that proteases from C. sinensis fruit peel are detergent stable which may be useful in laundry industries.Item Cofactor interactions in the activation of tissue non-specific alkaline phosphatase: Synergistic effects of Zn2+ and Mg2+ ions(Nigerian Society for Experimental Biology, 2007) Olorunniji, F.J.; Igunnu, Adedoyin; Adebayo, J.O.; Arise, R.O.; Malomo, S.O.The interactions of Mg2+ and Zn2+ ions in the activation of non-specific tissue alkaline phosphatase were investigated using crude extracts of rat kidney. Activation of alkaline phosphatase by the metal ions was accompanied by changes in the kinetic parameters of p nitrophenylphosphate hydrolysis. The results suggest some synergistic interactions between Mg2+ and Zn2+ ions in promoting the hydrolysis of p-nitrophenylphosphate by alkaline phosphatase. The results show that assays of alkaline phosphatase activity in homogenised tissue samples will give better responses if both Mg2+ and Zn2+ ions are included in the reactions.Item Combined oral contraceptive synergistically activates mineralocorticoid receptor through histone code modifications(Elsevier, 2015-10-23) Igunnu, Adedoyin; Young-Mi, Seok; Lawrence, A. Olatunji; Seol-Hee, Kang; Inkyeom, KimClinical studies have shown that the use of combined oral contraceptive in pre-menopausal women is associated with fluid retention. However, the molecular mechanism is still elusive. We hypothesized that combined oral contraceptive (COC) ethinyl estradiol (EE) and norgestrel (N) synergistically activates mineralocorticoid receptor (MR) through histone code modifications. Twelve-week-old female Sprague- Dawley rats were treated with olive oil (control), a combination of 0.1 mg EE and 1.0 mg N (low COC) or 1.0 mg EE and 10.0 mg N (high COC) as well as 0.1 or 1.0 mg EE and 1.0 or 10.0 mg N daily for 6 weeks. Expression of MR target genes in kidney cortex was determined by quantitative real-time polymerase chain reaction. MR was quantified by western blot. Recruitment of MR and RNA polymerase II (Pol II) on promoters of target genes as well as histone code modifications was analyzed by chromatin im- munoprecipitation assay. Treatment with COC increased renal cortical expression of MR target genes such as serum and glucocorticoid-regulated kinase 1 (Sgk-1), glucocorticoid-induced leucine zipper (Gilz), epithelial Na þ channel (Enac) and Na þ –K þ –ATPase subunit α 1 (Atp1a1). Although COC increased neither serum aldosterone nor MR expression in kidney cortex, it increased recruitment of MR and Pol II in parallel with increased H3Ac and H3K4me3 on the promoter regions of MR target genes. However, treatment with EE or N alone did not affect renal cortical expression of Sgk-1, Gilz, Enac or Atp1a1. These results indicate that COC synergistically activates MR through histone code modificationsItem Combined oral contraceptive-induced hypertension is accompanied by endothelial dysfunction and upregulated intrarenal angiotensin II type 1 receptor gene expression(Springer, 2016) Olatunji, L.A.; Seok, Y.; Igunnu, Adedoyin; Kang, S.; Kim, I.Combined oral contraceptive (COC) use is associated with increased risk of developing hypertension. Activation of the intrarenal renin-angiotensin system (RAS) and endothelial dysfunction play an important role in the development of hypertension.We tested the hypothesis that COC causes hypertension that is associated with endothelial dysfunction and upregulation of intrarenal angiotensin-converting enzyme 1 (Ace1) and angiotensin II type 1 receptor (At1r). Female Sprague-Dawley rats aged 12 weeks received (p.o.) olive oil (control) and a combination of 0.1 μg ethinyl estradiol and 1.0 μg norgestrel (low COC) or 1.0μg ethinyl estradiol and 10.0 μg norgestrel (high COC) daily for 6 weeks. Blood pressure was recorded by tail cuff plethysmography. Expression of genes in kidney cortex was determined by quantitative real time polymerase chain reaction. COC treatment led to increased blood pressure, circulating uric acid, C-reactive protein and plasminogen activator inhibitor-1, renal uric acid, and expression of renal Ace1 and At1r. COC treatment resulted in increased contractile responses to phenylephrine in endothelium-denuded aortic rings. Endothelium-dependent relaxation responses to acetylcholine, but not endothelium independent relaxation responses to nitric oxide (NO) donation by sodium nitroprusside, were attenuated in COC-exposed rings. Impaired relaxation responses to acetylcholine were masked by the presence of NO synthase inhibitor (L-NAME) in the COC-exposed rings, whereas the responses to acetylcholine in the presence of selective cyclooxygenase-2 inhibitor (NS-398) were enhanced. These findings indicate that COC induces hypertension that is accompanied by endothelial dysfunction, upregulated intrarenal Ace1 and At1r expression, and elevated proinflammatory biomarkers.Item Comparative Study on the Antioxidant Activities of Ethyl acetate and Methanolic Leaf Extracts of Celosia argentea(Nigeria Society of Biochemistry and Molecular Biology, 2014) Malomo, S.O.; Yakubu, M.T.; Amira, O.J.; Sulyman, A.O.; Dosumu, O.O.; Igunnu, Adedoyin; Oluwaniyi, O.O.; Arise, R.O.; Adebayo, J.O.The present study was carried out to compare the secondary metabolites, in vitro and in vivo antioxidant activities as well as the safety of ethyl acetate and methanolic extracts of Celosia argentea leaves in cadmium-induced oxidative stress in rats. The secondary metabolite screening was done by standard methods while the in vitro antioxidant activity of the extract was evaluated using ammonium thiocyanate, reducing power and diphenyl picryl hydrazyl (DPPH) radical scavenging models. In the in-vivo antioxidant and toxicological studies, thirty rats (Rattus novergicus) weighing 137.05 ± 5.84g were completely randomized into six groups (A-F) of five animals each. Animals in group A received orally 0.5ml of distilled water for 7 days while those in groups B, C, D, E and F received same volume corresponding to 8 mg/kg body weight (bw) of cadmium, in addition to simultaneous administration of distilled water, 100 mg/kg b.w of ascorbic acid, 100, 200 and 400 mg/kg b.w. of the extract respectively. Biochemical indices of in vivo antioxidant activities and toxicity were evaluated in the animals after the treatment period. The ethyl acetate extract of C. argentea contained saponins (1.67%), tannins (0.65%), cardenolide and dienolides (1.20%) and phenolics (0.42%) whereas the methanolic extract contained saponins (3.20%), tannins (0.65%), cardenolide and dienolides (0.006%) and phenolics (5.72%). Reducing sugar, steroids, and glycosides were only detected in the ethylacetate extract. The ethyl acetate extract and ascorbic acid, at 50 mg/ml, inhibited linoleic acid oxidation by 51.00 and 24.2% respectively whereas the methanolic extract produced 51.01% inhibition. Ethylacetate extract at 10, 50 and 100 mg/ml produced reducing power of 0.116, 0.092 and 0.127 nm whereas the methanolic extract produced 0.131, 0.185 and 0.183nm when compared with ascorbic acid that gave 0.092, 0.089 and 0.107 nm. The 100 μg/ml of both the ethyl acetate and methanolic extracts scavenged 82% and 30% respectively of the DPPH radical as against 65% in ascorbic acid. Both the extracts attenuated the cadmium chloride treatment related reduction in the activities of superoxide dismutase, catalase, alkaline phosphatase, gamma glutamyl transferase, alanine and aspartate transaminase as well as the levels of uric acid, albumin, total and conjugated bilirubin, total protein and the Cd elevated levels of malondialdehyde in the serum and tissues of the animals in a manner similar to that of the ascorbic acid treated animals and the non-Cd treated animals administered distilled water; with the ethyl acetate producing a better result. The totality of the results conferred antioxidant activity on the ethyl acetate extract and methanolic extract by the phenolic components of the extracts via induction of the antioxidant enzymes and scavenging of free radical. The extracts also reversed cadmium induced changes in the biomarkers of liver damage.Item Effects of co-administration of artesunate and amodiaquine on some cardiovascular disease indices in rats(Elsevier, 2011) Adebayo, J.O.; Igunnu, Adedoyin; Arise, R.O.; Malomo, S.O.The effects of co-administration of artesunate and amodiaquine on some cardiovascular disease indices were investigated in albino rats (Rattus novergicus). The experimental animals were randomly divided into four groups: those administered distilled water (control), those administered artesunate (2 mg/kg body weight), those administered amodiaquine (6.12 mg/kg body weight) and those co-administered artesunate (2 mg/kg body weight) and amodiaquine (6.12 mg/kg body weight). The drugs were orally administered twice daily for three days after which the serum lipid profile, heart MDA content and heart ALP and ACP activities were determined. Artesunate significantly reduced (P < 0.05) total cholesterol and HDL-cholesterol concentrations in the serum with no significant effects (P > 0.05) on other parameters compared to controls. Amodiaquine, on the other hand, significantly reduced (P < 0.05) serum total cholesterol concentration while it significantly increased (P < 0.05) serum LDL-cholesterol and heart ACP activity compared to controls. Co-administration of artesunate and amodiaquine significantly reduced (P < 0.05) total cholesterol and HDL-cholesterol concentrations in the serum while significantly increasing (P < 0.05) serum LDL-cholesterol concentration, atherogenic index (LDL-C/HDL-C) and ACP activity in the heart compared to controls. The results obtained suggest that co-administration of artesunate and amodiaquine to patients with coronary heart disease should be with caution.Item Effects of Cysteine-Stabilised Peptide Fraction of Aqueous Extract of Morinda lucida Leaf on Selected Cardiovascular Disease Indices in Mice(Springer, 2018) Adewole, K.E.; Igunnu, Adedoyin; Adebayo, J.O.This study evaluated the effects of cysteine-stabilised peptide fraction (CSPF) of aqueous extract of Morinda lucida leaf on selected cardiovascular disease indices in mice. Sixty adult Swiss Albino mice were randomly divided into 6 groups (n = 10). Group A served as control and received 5% DMSO. Half of the mice in groups B, C, D, E and F received 31.25, 62.5, 125, 250, and 500 mg/kg body weight of CSPF respectively for 7 days while the other half received the various doses for 28 days. After the experimental period, selected cardiovascular disease indices were determined in the mice. The results revealed that CSPF significantly reduced (p\0.05) atherogenic index, plasma concentrations of total cholesterol and LDL-cholesterol but significantly increased (p\0.05) plasma HDL-cholesterol concentration at higher doses after 28 days of administration. Plasma lactate dehydrogenase, aspartate aminotransferase and alkaline phosphatase activities were not significantly altered (p[0.05) at all doses of the CSPF after 7 and 28 days of administration compared to controls. After 7 days of CSPF administration, the activities of heart Ca2?, Mg 2?ATPase and Na?–K?-ATPase were not significantly altered (p[0.05) but heart Mg2?-ATPase activity was significantly increased (p\0.05) at 250 mg/kg body weight compared to controls. Also, 28 days of CSPF administration at all doses had no significant effect (p[0.05) on the activities of heart Mg2?-ATPase and Na?–K?-ATPase of mice compared to controls but heart Ca2?–Mg2?-ATPase activity was significantly increased (p\0.05) at the highest dose with no significant alteration (p[0.05) at other doses compared to controls. Generally, CSPF administration had no significant effect (p[0.05) on haematological parameters after 7 and 28 days. These results suggest that CSPF may not predispose subjects to cardiovascular diseases.Item Leaf extract of Morinda lucida improves pancreatic beta-cell function in alloxan-induced diabetic rats(Published by Informa UK Limited, trading as Taylor & Francis Group., 2019-09) Abdulkareem, A.O.; Igunnu, Adedoyin; Alad, A.A.; Olatunji, L.A.Chemotherapy remains the utmost treatment for Type 1 diabetes (T1D) patients. This however, predisposes the patients to a wide range of serious complications, thus, the need for alternative therapeutic agents that target pancreatic β-cell function. This study investigated the effects of aqueous leaf extract of M. lucida (MLE) on β-cell dysfunction and atherogenic dyslipidaemia in alloxan-induced T1D in rats. Twenty-five Wister rats (156- 168g) were randomly divided into normal, diabetic, diabetic + glibenclamide (5 mg/kg), diabetic + 120 mg/kg MLE and diabetic + 240 mg/kg MLE groups (n = 5/ group). Treatments were via oral route for 14 days. Our findings revealed that, 120 mg/kg MLE significantly reduced hyperglycaemia, improved insulinaemia as well as β-cell function, and attenuated weight loss in alloxan-induced diabetic rats. The extract also attenuated (p<0.05) atherogenic dyslipidaemia and malondialdehyde. The activities of the extract compared favourably with glibenclamide. This study suggested that, hypoglycaemic and mitigating effects of aqueous leaf extract of M. lucida on atherogenic dyslipidaemia and pancreatic β-cell dysfunction were through reduction in lipid peroxidation. The extract may therefore represent an effective source of novel drugs against TID and cardiovascular diseases. Further study is recommended, to explore the extract’s mechanism of oxidative repair.Item Metal Displacement Effects on Monoesterase Activity of Calf Intestinal Alkaline Phosphatase(Nigerian Society of Biochemistry and Molecular Biology, 2012) Igunnu, Adedoyin; Arise, R. O.; Adebayo, J. O.; Malomo, S. O.The mechanism of modulation of alkaline phosphatase activity by metal ions has not been fully elucidated. We investigated the time-dependent modulatory effects of Mg 2+ and Zn 2+ in promoting the hydrolysis of para-nitrophenyl phosphate (monoesterase reaction) by calf intestinal alkaline phosphatase (CIAP) and the effects of addition of the activating metal ions to the metal-inhibited enzyme. The CIAP was affected by changes in pre-incubation time in the presence of the two metal cofactors. Both Mg 2+ (0.1 – 0.25 mM) and Zn 2+ (0.1 – 5 mM) modulated Zn 2+ - and Mg 2+ - inhibited monoesterase activity of CIAP. The CIAP activity was inhibited when the enzyme was pre-incubated with 1 mM Ca 2+ . Further addition of Mg 2+ (0.1 – 2 mM) did not completely restore the activity though partly relieved the inhibition caused by Ca 2+ - pre-incubated enzyme. Again, addition of 2mM Zn 2+ to Ca 2+ - pre-incubated alkaline phosphatase completely restored the activity of the enzyme. This study suggests that Mg 2+ and Zn 2+ regulate the catalytic property of each other and modulate the inhibitory effect of Ca 2+ in alkaline phosphatase catalysis through a displacement effect. The modulation of Ca 2+ -inhibited CIAP activity by Mg 2+ and Zn 2+ may be explored in the treatment of disorders of bone mineralization especially those arising from inhibited alkaline phosphatase activity.Item Modulatory Effects of Mg2+ and Zn2+ Ions on Monoesterase Activity of Wildtype and Mutant E. coli Alkaline Phosphatases(Faculty of Physical Sciences, University of Ilorin, 2018) Igunnu, Adedoyin; Joel, E.B.; Ezetulugo, L.N.; Malomo, S.O.Metal cofactors and arginine-166 residue are active site participants in alkaline phosphatase catalysis. However, the mechanism by which the metal cofactors coordinate with arginine-166 residue during alkaline phosphatase catalysis is elusive. This study investigated the effects of Mg2+ and Zn2+ on monoesterase activity of wild-type and mutant E. coli alkaline phosphatases (ECAPs). The intact arginine-166 residue of wild-type ECAP was replaced by alanine and serine in the mutant ECAPs, R166A and R166S, respectively. Monoesterase activity of ECAP was measured by monitoring the rate of hydrolysis of para-nitrophenyl phosphate (pNPP). The monoesterase activity of wild-type ECAP was approximately 2-fold higher than the mutant ECAPs. Mg2+ (0.110mM) increased the activities of wild-type and mutant enzymes in a concentration-dependent manner. Zn2+ (0.05-0.1mM) slightly increased the activities of wild-type and mutants ECAPs. In the absence and in the presence of 10mM Mg2+ or 0.1mM Zn2+, the maximum reaction rate of wild-type ECAP was higher than those of the mutant ECAPs while its Michaelis constant was lower than those of the mutant ECAPs. Findings in this study revealed that monoesterase activity of ECAP was greatly reduced by the loss of arginine-166 residue but its modulation by Mg2+ and Zn2+ ions was independent of arginine-166 residue.Item Novel pectin from Parkia biglobosa pulp mediated green route synthesis of hydroxyapatite nanoparticles(Elsevier, 2019) Ibraheem, S.A.; Audu, E.A.; Jaafar, M.; Adudu, J.A.; Barminas, J.T.; Ochigbo, V.; Igunnu, Adedoyin; Malomo, S.O.Hydroxyapatite (HAP) nanoparticles were synthesized using pectin from pulp of P. biglobosa as green template. This was achieved at different concentrations (0.1, 0.5 and 1%) of pectin. The HAP nanoparticles mediated by pectin were characterized using Fourier Transform infrared (FTIR), Scanning electron Microscopy (SEM) and Xray Diffraction (XRD). Structure and morphology of the synthesized HAP indicate that discrete and less agglomerated particles were produced at low concentration (0.1%) of pectin. The HAP nanoparticles produced, with crystallite size ranging from 17.5 to 26.3 nm, inhibited the growth of selected bacteria used for the study. Findings from this study suggest that P. biglobosa pulp pectin can serve as a green template for the production of HAPnanoparticleswhichareconsideredtobepromisingandversatilebioactivematerialsinenzymetechnology, biomedical and tissue engineering.Item Oxalate: A potential ligand for differentiating Plasmodium berghei lactate dehydrogenase from host erythrocyte lactate dehydrogenase(University of Ilorin Library and Publication Committee, 2015) Igunnu, Adedoyin; Adebayo, J.O.; Malomo, S.O.Plasmodium lactate dehydrogenase is a valuable malaria diagnostic indicator. However, the difference between Plasmodium and host lactate dehydrogenase (LDH) activities in the presence of ligands has not been fully characterized. This study investigated the effects of Co2+ and oxalate on lactate dehydrogenase activities in Plasmodium berghei-infected erythrocyte (PBIE-LDH) and uninfected erythrocytes (UE-LDH) of mice. LDH activities in PBIE and UE were determined in the presence of varying concentrations of Co2+ and oxalate. Vmax of PBIE-LDH was three times higher (with reduced Km) than that of UE-LDH in the absence of the ligands. Co2+ activated both PBIE-LDH and UE-LDH activities with optimal concentrations at 10 mM and 5 mM respectively. Oxalate (0.1-10 mM) inhibited UE-LDH activity. Moreover, oxalate (from 0.1 to 2 mM) progressively inhibited PBIE-LDH activity but concentrations higher than 2 mM (up to 10 mM) progressively reversed this inhibition but not to the range of the enzyme activity in the absence of oxalate. Kinetic analyses revealed that Vmax of PBIE-LDH in the presence of 5 mM oxalate and 5 mM Co2+ was one and a half times and five times higher (with reduced Km) than those of UE-LDH respectively. These results suggest that the P. berghei LDH can be differentiated from host erythrocyte LDH in the presence of oxalate at concentrations higher than 2 mM. This could be of significance in antimalarial screening programmes and, by extension, effective diagnosis of malaria caused by other Plasmodium species and monitoring of recovery during treatment.Item Responses of selected haematological and biochemical parameters to artesunate/artemether-lumefantrin combination therapy in children with severe malaria(Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria., 2017) Okoli, C.A.; Igunnu, Adedoyin; Malomo, S.O.Item Responses of Selected Inflammatory, Kidney and Liver Function Markers in Serum of Nigerian Children with Severe Falciparum Malaria to Treatment with Artesunate/ArtemetherLumefantrine Combination Therapy(Department of Physiology, College of Medicine, University of Ibadan, Nigeria, 2019) Okoli, C.A.; Igunnu, Adedoyin; Malomo, S.O.; Adebayo, J.O.; Oguche, S.Malaria tolerance is a defence strategy that limits the damage caused by Plasmodium species irrespective of pathogen burden. The mechanisms responsible for this, responses of these mechanisms and their impact on organs to treatment have not been extensively studied. Thus, in this study, serum levels of selected pro- and anti-inflammatory markers, liver and kidney function indices with leucocytes indices in 100 children (1-10 years) with severe falciparum malaria were determined before treatment, at 48 hours during treatment and 48 hours after treatment with WHO recommended dosage of artesunate/artemether-lumefantrine combination therapy using standard methods. Data were analysed using SPSS, differences were considered significant at p<0.05. The results revealed that the serum levels of interleukin-12 (IL-12), interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), C-reactive protein (CRP), nitric oxide (NO), creatinine, albumin, total protein and conjugated bilirubin were not significantly changed at higher parasite densities before treatment. Only serum IL-4, CRP, total bilirubin, urea and creatinine levels and alanine aminotransferase activity were significantly reduced below the ranges of those with severe malaria. The results suggest a self-protective feed-back control, indicating tolerance, which reduced the adverse effects of the disease on kidney and liver functions at higher parasite densities. The results also suggest serum IL-12, IL-4, TNF-α, IFN-γ, CRP and NO levels as immune-protective markers for tolerance and serum IL-4 level as an effective marker for disease severity and recovery from the disease in children with severe malaria.