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BackgroundThe investigation and knowledge of calcium handling mechanisms in the plasmodium has been considered as a potential biological target against malaria.ObjectiveThis study deals with the evaluation of inhibitory activity of secondary metabolites of ethylacetate partitioned-fraction of Adansonia digitata stem bark extract on malaria-associated protein using in silico docking studies.Materials and methodsMolecular docking and virtual screening was performed to understand the mechanism of ligand binding and to identify potent calcium transporter inhibitors. The stem bark extracts of A. digitata contains rich sources of phytochemicals. The secondary metabolites were determined by HPLC-DAD and HRGC-MS analysis. The major chemical constituent present in the ethylacetate partitioned-fraction of A. digitata stem bark extract were examined for their antiplasmodial activity and were also involved in docking study.ResultsThe secondary metabolites, quercetin and apigenin inhibited the formation of β-hematin. The results showed that all the selected compounds in the A. digitata showed binding energy ranging between -6.5 kcal/mol and -7.1 kcal/mol. Among the two chemical constituents, apigenin has the highest docking score along with the highest number of hydrogen bonds formed when compared to quercetin. Analysis of the results suggests that apigenin and quercetin could act as an anti-malaria agent.ConclusionMolecular docking analysis could lead to further development of potent calcium transporter inhibitors for the prevention and treatment of malaria and related conditions.

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The stem bark of Enantia chlorantha is commonly used for the treatment of malaria and other ailments of the human body such as cough and wound. The plant had been intensely studied for its antimicrobial activities and antipyretic properties. However, the efficacy and mechanisms of action of the plant remain unclear. Therefore, the objective of the present study was to determine the in vitro antioxidant activity of the various solvent extracts from stem bark of Enantia chlorantha. In vitro antioxidant activity of certain extracts of stem bark of Enantia chlorantha such as methanol extract (ME), n-hexane, chloroform, ethylacetate, and aqueous fractions (HF, CF, EF and AF respectively) was evaluated using models of DPPH radical scavenging activity, ferric reducing property (FRAP), nitric oxide scavenging activity, hydroxyl radical scavenging activity. The inhibition of lipid oxidation, total flavonoids and phenolic contents of the extracts were also determined using spectrophotometric methods. The result revealed the highest phenolic and flavonoid contents in the methanol extract followed by AF, EF and CF while HF contained the least concentration. Free radical scavenging potentials of the extracts were found to be proportional to their respective phenolic and flavonoid contents. Our results suggest that part of the mechanisms through which the plant is used in folk medicine for the treatment of stress related diseases such as malaria, and cough and wound may be through its antioxidant activity, DPPH, nitric oxide , hydroxyl radical scavenging abilities and reducing power.[34] Halliwell, B., Gutteridge, J.M.C. and Aruoma, O.I. (1987) The deoxyribose method: A simple "test-tube" assay for determination of rate constants for reactions of hydroxyl radicals. Analytical Biochemistry, 165, 215-219.

Introduction Resistant malaria is a fatal disease. Globimetula braunii (African Mistletoe) is traditionally used for malarial treatment but this fact has not been scientifically reported. Methods Plasmodium berghei (NK65)-infected male Swiss mice (20±2 g) were treated orally and once daily with 100, 200, and 400 mg/kg BW of methanol extract and its respective hexane, dichloromethane and ethyl acetate fractions for 9 days. P-alaxin was used as control drug P. berghei (ANKA)-infected mice were then treated with the most potent fraction for 5 days. Parasitemia and parasite clearance were determined by microscopy, while hematological parameters, heme, hemozoin, and mouse erythrocyte membrane stabilisation were assayed. The phytochemicals in the most potent fraction were identified using gas chromatography-mass spectrometry. Results Hexane fraction (HF)-treated mice (400 mg/kg BW) had the least mean parasite load (0.00 ± 0.00; 0.14 ± 0.05%) and highest clearance (100 ± 0.00; 75.50 ± 4.95%) compared with infected control (9.81 ± 0.09; 6.84 ± 0.09%) in susceptible and resistant models, respectively. Hexane fraction modulated hematological indices, minimised erythrocyte membrane damage in heat-induced (2.18 ± 0.94%) and hypotonic solution-induced (7.93 ± 0.93%) compared to artequin (5.05 ± 2.18; 6.38 ± 0.33%) and P-alaxin (67.45 ± 5.15; 56.78 ± 1.10%) in both models of membrane stabilisation, respectively. Hexane fraction ( P <0.01) increased heme and decreased hemozoin contents. Friedelan-3-one was identified as the most abundant triterpene. Conclusion The results indicated that G. braunii has anti-plasmodial properties and minimally dis-stabilised erythrocyte membrane. The major findings in this study are that n -hexane fraction of G. braunii possess excellent and moderate antiplasmodial activity against susceptible and resistant P. berghei , respectively. This was reflected via decreased parasite load, improved hematological parameters, increased heme and decreased hemozoin contents. Friedelan-3-one, a major constituent of the n-hexane fraction, may be responsible for this activity.

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Background Trema orientalis (T. orientalis Linn) has been used in the management of malaria in the western part of Nigeria and despite its application in ethnomedicine, there is dearth of scientific evidence to justify the acclaimed prophylactic antimalarial usage of the plant. The aim of this study is to assess the in vitro antiplasmodial cell-free assay and chemopreventive efficacy of the methanol extract of the stem bark of T. orientalis and its fractions as a prophylactic regimen for malaria prevention. Also, the antimicrobial activities of the extract and the fractions were investigated.MethodVacuum liquid chromatography was used to obtain dichloromethane, ethylacetate and methanol fractions from the methanol extract of T. orientalis. The fractions were tested for their prophylactic and cell-free antimalarial activity using murine models and β-hematin formation assay respectively. Disc diffusion method was used to determine the antibacterial activity of the extract and its fractions against both Gram-positive and Gram-negative bacteria.ResultsIn the prophylactic experiment, dichloromethane (DCMF), methanol fraction (MF) and extract (ME) (in this order) showed significant chemopreventive effects against P. berghei invasion of the red blood cells when compared with both Sulfadoxine-Pyrimethamine (SP) and untreated controls. Results of the in vitro study showed that the DCMF had the highest effect in preventing the formation of β-hematin when compared with other fractions. The DCMF also had the highest percentage inhibition of β-hematin formation when compared with chloroquine. The extract and fractions showed a concentration dependent antibacterial activity. Methanol extract had a pronounced inhibitory effect on Enterobacter cloaca ATCC 13047 and Enterococcus faecalis ATCC 29212. Serratia mercescens ATCC 9986 and Pseudomonas aeruginosa ATCC 19582 were the most susceptible bacteria.ConclusionThe results obtained showed that both extract and fractions of T. orientalis possessed antiplasmodial and antimicrobial activity.