Cholinergic Inhibition and Antioxidant Potential of Gongronema latifolium Benth Leaf in Neurodegeneration: Experimental and In Silico Study.

The use of Gongronema latifolium for the management of various forms of neurological disorders has generated a lot of interest in the need to further investigate its neurotherapeutic constituents. This work, therefore, focused on assessing the inhibitory potential of selected bioactive components derived from G. latifolium against key neurotherapeutic targets and oxidant species associated with neurodegeneration using in vitro analysis and biomolecular modelling. G. latifolium methanol extract (GLME), solvent partition, chromatographic fractions (A-F) of GLME and pregnane compounds (Iloneoside and marsectohexol) derived from fraction-B with the highest activity were investigated for in vitro acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidase (MAO) inhibition in addition to their in vitro antioxidant activities. The interactions of iloneoside, marsectohexol, and reference drugs with human acetylcholinesterase, butyrylcholinesterase, and ß-secretase (BACE-1) were further assessed using molecular docking, binding free energy calculations, cluster analysis, and molecular dynamics simulations. The GLME and fractions inhibited the activities of both acetylcholinesterase and butyrylcholinesterase in a dose-dependent manner. Iloneoside and marsectohexol exhibited in vitro concentration-dependent inhibitory activities against acetylcholinesterase (IC50 = 19.28, 184.9 µM, respectively) and butyrylcholinesterase (IC50 = 30.75, 43.4 µM, respectively). These compounds also possess ferric ion-reducing, hydroxyl, and superoxide radical-scavenging activities. Iloneoside had the highest docking scores of -9.8, -9.9 -9.4 Kcal for AChE, BChE, and BACE1, respectively. The stability of the interaction of the bioactive compounds with the catalytic residues of the protein targets was preserved in a 100 ns molecular dynamics simulation. Iloneoside, a rare pregnane glycoside, was identified as a neurotherapeutic constituent of G. latifolium leaf. Further studies are suggested to investigate the neurotherapeutic potential in animal models.

Antimalarial and antioxidant activities of novel artesunate-ellagic acid hybrid compound in vitro and in vivo.

Introduction: Emergence of drug resistant strains of Plasmodium species has necessitated the search for novel antimalarials with unique mechanisms of action. Synthesis of hybrid compounds has been one approach to tackling this challenge. In this study, the synthesis of artesunate-ellagic acid hybrid compound (EA31) from ellagic acid and artesunate and its evaluation for antimalarial and antioxidant activities using in vitro and in vivo models were carried out. Method: EA31 was synthesized from artesunate and ellagic acid. The activities of the hybrid compound against Plasmodium falciparum W2 and P. berghei NK65 were evaluated, and its antioxidant activities were also determined. Results: The results revealed that EA31 was more active against P. falciparum W2 (chloroquine resistant) clone and less cytotoxic to buffalo green monkey kidney cell line compared to artesunate. EA31 was also active against Plasmodium berghei NK65 in vivo. The results revealed inhibition of ß-hematin formation as one of the mechanisms of action of EA31. EA31 also exhibited antioxidant activities. Conclusion: The results revealed that EA31 may exert dual action of killing malaria parasite and mopping the reactive oxygen species that mediate the secondary complications of malaria.

Piperine Enhances Antimalarial Activity of Methyl Gallate and Palmatine Combination.

PURPOSE: Artemisinin combination therapies, the first-line antimalarials in Nigeria, have reportedly suffered multiple failures in malaria treatment, hence the search for novel combination of other compounds. Methyl gallate and palmatine have been reported to exhibit antiplasmodial activities but the antimalarial activity of their combination has not been evaluated. Therefore, the evaluation of the combination of methyl gallate and palmatine for antimalarial activity in vitro and in vivo in the presence of piperine was carried out. MATERIALS AND METHODS: The inhibitory potential of methyl gallate and palmatine combination on ß-hematin (hemozoin) formation was studied in vitro. Also, the antimalarial activity of methyl gallate and palmatine combination with/without a bioenhancer (piperine) was evaluated in Plasmodium berghei NK65-infected mice. RESULTS: Methyl gallate and palmatine in the ratio 3:2 acted synergistically in vitro and had the highest inhibitory effect (IC50 = 0.73 µg/mL) on ß-hematin (hemozoin) formation. The 3:2 combination of methyl gallate and palmatine exhibited no antimalarial activity in vivo in the absence of piperine but caused reduction in parasitemia that exceeded 40% in the presence of piperine at the dose of 25 mg/kg body weight on days 6 and 8 post-inoculation in mice. CONCLUSION: The 3:2 combination of methyl gallate and palmatine in the presence of piperine exhibited antimalarial activity in vivo, possibly by synergistic inhibition of hemozoin formation which may cause accumulation of haem within the food vacuole of Plasmodium spp. and its death.

Potentials of Terpenoids as Inhibitors of Multiple Plasmodium falciparum Protein Drug Targets.

PURPOSE: The resistance of parasite to readily affordable antimalarial drugs, the high cost of currently potent drugs, and the resistance of vector mosquitoes to insecticides threaten the possibility of malaria eradication in malaria endemic areas. Due to the fact that quinine and artemisinin were isolated from plants sources, researchers have been encouraged to search for new antimalarials from medicinal plants. This is especially the case in Africa where a large percentage of the population depends on medicinal plant to treat malaria and other ailments. METHOD: In this study, we evaluated previously characterized Plasmodium-cidal compounds obtained from the African flora to identify their likely biochemical targets, for an insight into their possible antimalarial chemotherapy. Molecular docking study was first conducted, after which remarkable compounds were submitted for molecular dynamic (MD) simulations studies. RESULTS: From a total of 38 Plasmodium-cidal compounds docked with confirmed Plasmodium falciparum protein drug targets [plasmepsin II (PMII), histo-aspartic protein (HAP) and falcipain-2 (FP)], two pentacyclic triterpene, cucurbitacin B and 3 beta-O-acetyl oleanolic acid showed high binding affinity relative to artesunate. This implies their capacity to inhibit the three selected P. falciparum target proteins, and consequently, antimalarial potential. From the MD simulations studies and binding free energy outcomes, results confirmed that the two compounds are stable in complex with the selected antimalarial targets; they also showed excellent binding affinities during the 100 ns simulation. CONCLUSION: These results showed that cucurbitacin B and 3 beta-O-acetyl oleanolic acid are potent antimalarials and should be considered for further studies.

Identification of potential inhibitors of cholinergic and ß-secretase enzymes from phytochemicals derived from Gongronema latifolium Benth leaf: an integrated computational analysis.

Neurodegenerative disorders (NDDs) are associated with increased activities of the brain acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and ß-secretase enzyme (BACE1). Inhibition of these enzymes affords therapeutic option for managing NDDs such as Alzheimer's disease (AD) and Parkinson's disease (PD). Although, Gongronema latifolium Benth (GL) has been widely documented in ethnopharmacological and scientific reports for the management of NDDs, there is paucity of information on its underlying mechanism and neurotherapeutic constituents. Herein, 152 previously reported Gongronema latifolium derived-phytochemicals (GLDP) were screened against hAChE, hBChE and hBACE-1 using molecular docking, molecular dynamics (MD) simulations, free energy of binding calculations and cluster analysis. The result of the computational analysis identified silymarin, alpha-amyrin and teraxeron with the highest binding energies (-12.3, -11.2, -10.5 Kcal/mol) for hAChE, hBChE and hBACE-1 respectively as compared with those of the reference inhibitors (-12.3, -9.8 and - 9.4 for donepezil, propidium and aminoquinoline compound respectively). These best docked phytochemicals were found to be orientated in the hydrophobic gorge where they interacted with the choline-binding pocket in the A-site and P-site of the cholinesterase and subsites S1, S3, S3' and flip (67-75) residues of the pocket of the BACE-1. The best docked phytochemicals complexed with the target proteins were stable in a 100 ns molecular dynamic simulation. The interactions with the catalytic residues were preserved during the simulation as observed from the MMGBSA decomposition and cluster analyses. The presence of these phytocompounds most notably silymarin, which demonstrated dual high binding tendencies to both cholinesterases, were identified as potential neurotherapeutics subject to further investigation.

Antioxidant activities of artesunate-procyanidin hybrid compound in erythrocyte and liver of Plasmodium berghei NK65-infected mice.

Resistance of malaria parasites to conventionally used antimalarial drugs has necessitated the search for new potent antimalarials, especially those that can also ameliorate oxidative stress-mediated secondary complications. This has led to the synthesis of an antimalarial artesunate-procyanidin hybrid compound (PC14), but it has not been evaluated for its antioxidant activity. This study was carried out to evaluate the antioxidant activities of PC14 in the erythrocyte and liver of Plasmodium berghei NK65-infected mice. A hundred mice were randomly divided into 10 equal groups (A-J). Mice in Groups B-J were inoculated with P. berghei NK65 while group A mice were not inoculated. Starting from Day 3 post-inoculation, dimethyl sulfoxide (DMSO) (5%) was administered to mice in Groups A and B (normal and negative controls, respectively), while various doses of chloroquine, artesunate, procyanidin, and PC14 were administered to their respective groups for 3 days. Thereafter, antioxidant parameters were determined in the erythrocyte and liver on Days 6 and 10 post-inoculation. A significant increase (P < 0.05) was observed in malondialdehyde levels in the erythrocyte and liver of negative control on Day 10 post-inoculation compared to normal controls. Significant reduction (P < 0.05) was observed in activities of liver catalase and superoxide dismutase and erythrocyte glutathione peroxidase and glutathione-S-transferase of negative control on Days 6 and 10 compared to normal controls. However, PC14 at various doses significantly (P < 0.05) reversed these alterations. The results suggest that PC14 possesses antioxidant activity, and it enhanced antioxidant defense in the erythrocyte and liver of P. berghei-infected mice.

Studies on Activities and Chemical Characterization of Medicinal Plants in Search for New Antimalarials: A Ten Year Review on Ethnopharmacology.

Malaria is an endemic disease that affected 229 million people and caused 409 thousand deaths, in 2019. Disease control is based on early diagnosis and specific treatment with antimalarial drugs since no effective vaccines are commercially available to prevent the disease. Drug chemotherapy has a strong historical link to the use of traditional plant infusions and other natural products in various cultures. The research based on such knowledge has yielded two drugs in medicine: the alkaloid quinine from Cinchona species, native in the Amazon highland rain forest in South America, and artemisinin from Artemisia annua, a species from the millenary Chinese medicine. The artemisinin-based combination therapies (ACTs), proven to be highly effective against malaria parasites, and considered as "the last bullet to fight drug-resistant malaria parasites," have limited use now due to the emergence of multidrug resistance. In addition, the limited number of therapeutic options makes urgent the development of new antimalarial drugs. This review focuses on the antimalarial activities of 90 plant species obtained from a search using Pubmed database with keywords "antimalarials," "plants" and "natural products." We selected only papers published in the last 10 years (2011-2020), with a further analysis of those which were tested experimentally in malaria infected mice. Most plant species studied were from the African continent, followed by Asia and South America; their antimalarial activities were evaluated against asexual blood parasites, and only one species was evaluated for transmission blocking activity. Only a few compounds isolated from these plants were active and had their mechanisms of action delineated, thereby limiting the contribution of these medicinal plants as sources of novel antimalarial pharmacophores, which are highly necessary for the development of effective drugs. Nevertheless, the search for bioactive compounds remains as a promising strategy for the development of new antimalarials and the validation of traditional treatments against malaria. One species native in South America, Ampelozyzyphus amazonicus, and is largely used against human malaria in Brazil has a prophylactic effect, interfering with the viability of sporozoites in in vitro and in vivo experiments.

Structure-based virtual screening suggests inhibitors of 3-Chymotrypsin-Like Protease of SARS-CoV-2 from Vernonia amygdalina and Occinum gratissimum.

Antiviral culinary plants are potential bioresources for preventive nutraceuticals and/or antiviral drugs in COVID-19. Structure-based virtual screening was undertaken to screen 173 compounds previously reported from Vernonia amygdalina and Occinum gratissimum for direct interaction with the active site of the 3-Chymotrypsin-Like Protease (3CLpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Based on docking scores and comparison with reference inhibitors, a hit-list of 10 top phytocompounds was defined, which also had strong interactions with the catalytic centre of 3CLpro from three related strains of coronavirus (SARS-CoV, MERS-CoV, HKU4). Among these, six compounds (neoandrographolide, vernolide, isorhamnetin, chicoric acid, luteolin, and myricetin) exhibited the highest binding tendencies to the equilibrated conformers of SARS-CoV-2 3CLpro in an in-depth docking analysis to 5 different representative conformations from the cluster analysis of the molecular dynamics simulation (MDS) trajectories of the protein. In silico drug-likeness analyses revealed two drug-like terpenoids viz: neoandrographolide and vernolide as promising inhibitors of SARS-CoV-2 3CLpro. These structures were accommodated within the substrate-binding pocket; and interacted with the catalytic dyad (Cys145 and His41), the oxyanion loop (residues 138-145), and the S1/S2 sub-sites of the enzyme active site through the formation of an array of hydrogen bonds and hydrophobic interactions. Molecular dynamics simulation and binding free energy calculation revealed that the terpenoid-enzyme complexes exhibit strong interactions and structural stability. Therefore, these compounds may stabilize the conformation of the flexible oxyanion loop; and thereby interfere with the tetrahedral oxyanion intermediate formation during the proteolytic activity of the enzyme.

Dual targeting of cytokine storm and viral replication in COVID-19 by plant-derived steroidal pregnanes: An in silico perspective.

The high morbidity and mortality rate of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection arises majorly from the Acute Respiratory Distress Syndrome and "cytokine storm" syndrome, which is sustained by an aberrant systemic inflammatory response and elevated pro-inflammatory cytokines. Thus, phytocompounds with broad-spectrum anti-inflammatory activity that target multiple SARS-CoV-2 proteins will enhance the development of effective drugs against the disease. In this study, an in-house library of 117 steroidal plant-derived pregnanes (PDPs) was docked in the active regions of human glucocorticoid receptors (hGRs) in a comparative molecular docking analysis. Based on the minimal binding energy and a comparative dexamethasone binding mode analysis, a list of top twenty ranked PDPs docked in the agonist conformation of hGR, with binding energies ranging between -9.8 and -11.2 kcal/mol, was obtained and analyzed for possible interactions with the human Janus kinases 1 and Interleukins-6 and SARS-CoV-2 3-chymotrypsin-like protease, Papain-like protease and RNA-dependent RNA polymerase. For each target protein, the top three ranked PDPs were selected. Eight PDPs (bregenin, hirundigenin, anhydroholantogenin, atratogenin A, atratogenin B, glaucogenin A, glaucogenin C and glaucogenin D) with high binding tendencies to the catalytic residues of multiple targets were identified. A high degree of structural stability was observed from the 100 ns molecular dynamics simulation analyses of glaucogenin C and hirundigenin complexes of hGR. The selected top-eight ranked PDPs demonstrated high druggable potentials and favourable in silico ADMET properties. Thus, the therapeutic potentials of glaucogenin C and hirundigenin can be explored for further in vitro and in vivo studies.

Dietary stigmastane-type saponins as promising dual-target directed inhibitors of SARS-CoV-2 proteases: a structure-based screening.

Despite the development of COVID-19 vaccines, at present, there is still no approved antiviral drug against the pandemic. The SARS-CoV-2 3-chymotrypsin-like proteases (S-3CLpro) and papain-like protease (S-PLpro) are essential for the viral proliferation cycle, hence attractive drug targets. Plant-based dietary components that have been extensively reported for antiviral activities may serve as cheap sources of preventive nutraceuticals and/or antiviral drugs. A custom-made library of 176 phytochemicals from five West African antiviral culinary herbs was screened for potential dual-target-directed inhibitors of S-3CLpro and S-PLpro in silico. The docking analysis revealed fifteen steroidal saponins (FSS) from Vernonia amygdalina with the highest binding tendency for the active sites of S-3CLpro and S-PLpro. In an optimized docking analysis, the FSS were further docked against four equilibrated conformers of the S-3CLpro and S-PLpro. Three stigmastane-type steroidal saponins (vernonioside A2, vernonioside A4 and vernonioside D2) were revealed as the lead compounds. These compounds interacted with the catalytic residues of both S-3CLpro and S-PLpro, thereby exhibiting dual inhibitory potential against these SARS-CoV-2 cysteine proteases. The binding free energy calculations further corroborated the static and optimized docking analysis. The complexed proteases with these promising phytochemicals were stable during a full atomistic MD simulation while the phytochemicals exhibited favourable physicochemical and ADMET properties, hence, recommended as promising inhibitors of SARS-CoV-2 cysteine proteases.

Influence of gender on the distribution of type 2 diabetic complications at the obafemi awolowo teaching hospital, Ile-Ife, Nigeria.

BACKGROUND: Sex specific differences appear particularly relevant in the management of type 2 DM. OBJECTIVE: We determined gender specific differences in cardio-metabolic risk, microvascular and macrovascular complications in patients with type 2 diabetes. METHODS: Four hundred type 2 diabetes patients, males and females, matched for age and disease duration were recruited from the diabetes clinic. Relevant clinical and laboratory information were obtained or performed. RESULTS: 190(47.5%) were male and 210 (52.5%) were female respectively. The mean age of the study population was 60.6 + 9.93 years. Women had higher prevalence of hypertension (and obesity. Mean total cholesterol was significantly higher in women but men were more likely to achieve LDL treatment goals than women (69.5% vs 59.0%, p<0.05). More women (47.1% & 31.4%) reached glycaemic goals of <10mmol/l for 2HPP and HBA1c of <7.0%.There were no gender differences in the distribution of microvascular and macrovascular complications (p>0.05) but women were more likely to develop moderate and severe diabetic retinopathy (p= 0.027). CONCLUSION: Women with T2DM had worse cardiometabolic risk profile with regards to hypertension, obesity and lipid goals. Men achieved therapeutic goals less frequently than did women in terms of glycaemia. Microvascular and macrovascular complications occurred commonly in both sexes.

Antioxidant defense system induced by cysteine-stabilized peptide fraction of aqueous extract of Morinda lucida leaf in selected tissues of Plasmodium berghei-infected mice.

OBJECTIVE: This study evaluated the responses of some antioxidant parameters in selected tissues of Plasmodium berghei-infected mice treated with cysteine-stabilized peptide fraction (CSPF) of aqueous extract of Morinda lucida leaf. METHODS: Fifty-six mice were randomly divided into seven groups. Group A (normal control) was uninfected and received 5% dimethyl sulfoxide (DMSO). Mice in Groups B (negative control), C, D, E and F were inoculated with P. berghei NK65 and were administered with 5% DMSO and 15.63, 31.25, 61.5 and 125 mg/kg body weight of CSPF respectively. Group G animals, were also inoculated with P. berghei NK65, and received 20 mg/kg body weight of chloroquine. The administration lasted for three days, after which malondialdehyde (MDA) concentration and various antioxidant parameters in selected tissues of mice were determined on days 4 and 8 post-inoculation. RESULTS: The results revealed that MDA concentration was significantly increased (P < 0.05) in the tissues of the negative control and chloroquine-treated groups. The increased MDA concentration was reduced by CSPF in a dose-dependent manner, which was significant (P < 0.05) at higher doses. The activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase and the concentration of reduced glutathione were significantly reduced (P < 0.05) in the tissues of the negative control animals compared to the normal controls. This observed reduction in the negative control animals was reverted in a dose-dependent manner in infected animals given CSPF, even to the range of the normal controls at highest dose, as did chloroquine. CONCLUSION: The results suggest that CSPF of M. lucida leaf extract may induce the antioxidant defense system in vivo against Plasmodium species infection.

Cysteine-stabilised peptide extract of Morinda lucida (Benth) leaf exhibits antimalarial activity and augments antioxidant defense system in P. berghei-infected mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Cysteine-stabilised peptides (CSP) are majorly explored for their bioactivities with applications in medicine and agriculture. Morinda lucida leaf is used indigenously for the treatment of malaria; it also contains CSP but the role of CSP in the antimalarial activity of the leaf has not been evaluated. AIM OF THE STUDY: This study was therefore performed to evaluate the antimalarial activity of partially purified cysteine-stabilised peptide extract (PPCPE) of Morinda lucida leaf and its possible augmentation of the antioxidant systems of liver and erythrocytes in murine malaria. MATERIALS AND METHODS: PPCPE was prepared from Morinda lucida leaf. The activity of PPCPE was evaluated in vitro against Plasmodium falciparum W2 and its cytotoxicity against a BGM kidney cell line. PPCPE was also evaluated for its antimalarial activity and its effects on selected liver and erythrocyte antioxidant parameters in P. berghei NK65-infected mice. RESULTS: PPCPE was not active against P. falciparum W2 (IC50: >50µg/ml) neither was it cytotoxic (MLD50: >1000µg/ml). However, PPCPE was active against P. berghei NK65 in vivo, causing 51.52% reduction in parasitaemia at 31.25mg/Kg body weight on day 4 post-inoculation. PPCPE significantly reduced (P < 0.05) malondialdehyde concentrations in the liver and erythrocyte at higher doses compared to untreated controls. PPCPE increased glutathione concentration and activities of glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase in a dose-dependent manner, which was significant (P < 0.05) at higher doses compared to the untreated controls. CONCLUSION: The results suggest that PPCPE may require bioactivation in vivo in order to exert its antimalarial effect and that PPCPE may augment the antioxidant defense system to alleviate the reactive oxygen species-mediated complications of malaria.

Effects of aqueous extract of Hibiscus sabdariffa on renal Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in Wistar rats.

OBJECTIVE: To investigate the effects of oral administration of aqueous extract of Hibiscus sabdariffa on renal Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in rats. METHODS: The 25 and 50 mg/(kg·d) of aqueous extracts of H. sabdariffa were respectively given to rats in the experimental groups for 28 d, and rats in the control group received an appropriate volume of distilled water as vehicle. Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in the kidney were assayed by spectrophotometric method. RESULTS: Administrations of 25 and 50 mg/(kg·d) of aqueous extract of H. sabdariffa significantly decreased the Ca(2+)-Mg(2+)-ATPase activity in the kidney of rats (P<0.05). However, the renal Na(+)-K(+)-ATPase activity of the experimental rats was not affected by either dose of the extract. And the plasma Na(+), K(+) and Ca(2+) levels of the experimental rats had no significant changes. Administration of either dose of the extract did not result in any significant changes in body and kidney weights, the concentrations of plasma albumin and total protein, and alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase activities. However, concentrations of creatinine and urea were significantly reduced by 50 mg/kg of the extract (P<0.05). CONCLUSION: The present study indicates that oral administration of aqueous extract of H. sabdariffa may preserve the renal function despite a decreased renal Ca(2+)-Mg(2+)-ATPase activity.

Ethanolic extract of Clerodendrum violaceum Gürke leaves enhances kidney function in mouse model of malaria.

Evaluation of the effects of daily oral administration of ethanolic extract of C. violaceum leaves (13 mg/kg body weight) for 5 days on some kidney function indices of uninfected and Plasmodium berghei-infected mice was done on days 3, 8 and 14 post-infection. The indices studied include serum urea and creatinine concentrations with the specific activities of alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase in the kidney. Treatment of P. berghei-infected mice with ethanolic extract of C. violaceum leaves (13 mg/kg body weight) for 5 days was able to ameliorate significantly the alterations in the various parameters observed in infected untreated mice, comparing favourably with chloroquine treatment in most cases. Administration of extract to uninfected mice had no significant effect on both serum and kidney parameters compared to the uninfected control. The results suggest that the ethanolic extract of C. violaceum leaves does not adversely affect kidney function at the dose used in traditional medicine for the treatment of malaria but rather enhances it.

Testing of natural products and synthetic molecules aiming at new antimalarials.

The search for new antimalarials, which in the past relied on animal models, is now usually performed with cultures of Plasmodium falciparum (PF) blood parasites by evaluation of parasite growth inhibition. Field isolates of PF human malaria parasite, parasite strains and clones, well characterized for their susceptibility to chloroquine and other standard antimalarials are available for the in vitro tests. The simplest method to evaluate parasite growth is the determination of parasitemias in Giemsa stained blood smears through light microscopy. Other methodologies have proven to be more precise and allow mass screening of new compounds against PF blood stages, such as: (i) measuring the incorporation of radioactive hypoxanthine by the parasites; (ii) indirect colorimetric assays in which specific parasite enzyme activities, and histidine-rich protein II (HRP2) production are measured with the help of monoclonal antibodies; (iii) the beta-haematin formation, and; (iv) assays using green fluorescent protein (GFP) in gene-expressing parasites. The advantages and disadvantages of the different in vitro screening methods, as well as the different in vivo models for antimalarial tests, are described in this review. Such tests can be used for the evaluation of medicinal plants, synthetic and hybrid molecules or drug combinations.

Effect of ethanolic extract of Khaya senegalensis on some biochemical parameters of rat kidney.

The effect of administration of ethanolic extract of Khaya senegalensis (2mg/kg body weight) on some biochemical parameters of rat kidney were investigated. Experimental animals were randomly divided into the control, those administered with the extract for 6 days and those administered with extract for 18 days, respectively. The prolonged administration of the extract resulted in significant reduction in the alkaline phosphatase activities of the kidney and its body weight ratio (P<0.05). In contrast, the same prolonged administration of the extract resulted in significant increase in the serum sodium ion concentration (P<0.05) while there was no significant difference in serum potassium ion concentration when compared to control (P>0.05). Administration of the extract for 6 days produced no significant difference from the control values in all the parameters investigated except in serum urea concentration which produced a significant increase (P<0.05). The available evidence in this study suggest that the ethanolic extract of Khaya senegalensis exerted more deleterious effect on the kidney when administered continuously over a prolonged period than a short one and this will adversely affect the functioning of the kidney.