Effets des extraits totaux aqueux de mallotus oppositifolium et de euphorbia hirta (euphorbiaceae) sur l’activite contractile intestinale du rat

Effects of total aqueous extracts of Mallotus oppositifolium and Euphorbia hirta (Euphorbiaceae) on intestinal contractile activity of the rat. - The contractile activity of the total aqueous extract of Mallotus oppositifolium (Mo) and Euphorbia hirta (Eh) leaves was investigated. Mo extracts (1.32 mg/mL) demonstrated inhibiting effect on the stimulation of rat ileal contractions by acetylcholine (-9 mm) and potassium chloride (-7 mm). Administrated before the magnesium sulfate (6 g/kg), Mo extracts reduce the faeces quantity (- 11g,

Anti-dyslipidemic and Antioxidant Potentials of Methanol Extract of Kalanchoe crenata Whole Plant in Streptozotocin-induced Diabetic Nephropathy in Rats

Purpose: The activity of the methanol extract of the whole plant of Kalanchoe crenata (MEKC) was studied for the treatment of diabetes-induced nephropathy in rats.Methods: Five-day old Wistar rats received a single intraperitoneal streptozotocin injection (90 ìg/kg body weight) to induce diabetes. Kidney disease onset in the rats was observed six weeks after diabetes induction. The rats were orally administered MEKC (0, 50 and 68 mg/kg) or glibenclamide (5 mg/kg), once daily for 6 weeks. Blood and urine glucose, proteins, lipids, creatinine, malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) were then evaluated.Results: After 6 weeks of treatment, 50 and 68 mg/kg MEKC, and glibenclamide significantly (p < 0.01) decreased glycaemia (-35, -44 and -39 %), glycosuria (-38, -47 and -61 %) and proteinuria (-82, -80 and-72 %) in diabetes-nephropathic rats. The extract (68 mg/kg) decreased MDA by up to -44 % (blood), -35 % (liver) and -34 % (kidney); increased SOD up to 257 % (blood), 116 % (liver) and 118 % (kidney); and CAT by up to 176 % (blood), 78 % (liver) and 96 % (kidney) in the rats, compared with nephropathic control. The extract (50 and 68 mg/kg, respectively) lowered (p < 0.01) total cholesterolemia (-24 and - 27 %), blood triglycerides (-55 and -54 %), blood LDL cholesterol (-48 and -59 %), but increased blood HDL cholesterol (71 and 58 %). Overall, atherogenic index was decreased by 31 %.Conclusion: The results indicate that MEKC holds promise for the development of a standardized phytomedicine for diabetes mellitus and kidney disease treatment.Keywords: Diabetes, Dyslipidemia, Antioxidant, Kalanchoe crenata extract, Nephropathy

Antioxidative properties of Mallotus oppositifolium decoction leaves extract using in vitro models

In an attempt to explain the scientific basis for the medicinal benefits of Mallotus oppositifolium (Euphorbiaceae), the phytochemical constituent and the antioxidative properties of the aqueous decoction leaves extract of the plant versus standard Vitamin C were assessed. The phytochemical analysis (screening and quantitative assay), the 1,1- Diphenyl-2-picrylhydrazyl (DPPH), Nitric oxide, and hydroxyl radicalscavenging, the reducing power, ferrous reducing antioxidant power (FRAP) and the β carotene bleaching of the extract were performed using colorimetric or spectrophotometric methods. Qualitative screening of the extract showed the presence of alkaloids, flavonoids, steroids, phenolic compounds, tannins, phlobatannins, saponins, lipids, carbohydrates, mucilages, and proteins. The phytochemical quantitative assay of the decoction extract revealed that the plant depicted flavonols (38.278 mg.g-1 catechin equivalent), tannins (23.13 mg.g-1 tannic acid equivalent), phenolics (13.73 mg.g-1 tannic acid content), flavonoids (10.62 mg.g-1 quercetin equivalent), proanthocyanidins (2.53 mg.g-1 quercetin equivalent) contents. Alkaloids and saponins content were 200 mg.g-1 and 285 mg.g-1, respectively. The ferric reducing antioxidant power (FRAP) of Mo extract and the IC50 of vitamin C were 228±0.4 mg.mL-1 and 592.0±0.8 mg.mL-1 , respectively. The DPPH radicalscavenging properties of IC50 of vitamin C was 480.0±0.8mg.mL-1 and that of Mo extract was 360.0±0.8 mg.mL-1. The IC50 of Mo’s reduce abilities was 39.2±0.8 mg.mL-1 and that of vitamin C was 320.0±0.8 mg.mL-1.The IC50 of the hydroxyl radical scavenging activity of Mo was 75.2±0,8 mg.mL-1 whereas that of IC50 of vitaminC was not defined. The nitric oxide radical scavenging activity of IC50 of Mo was 121.6±0.8 mg.mL-1 and that of the vitamin C was 130.4±0.8 mg.mL-1, respectively. The β carotene bleanching gives the IC50 of M. oppositifolium was 12,0±0,0 mg.mL-1 and for the vitamin C was 16.0±0,0 mg.mL-1. The decoction leaves of Mallotus oppositifolium (Mo) exhibited powerful antioxidative properties as vitamin C. The plant can be a source of antioxidative materials.Keywords: Traditional medicine, phytochemical analysis, antioxidan

Effets de l’extrait au cyclohexane de bidens pilosa l. (asteraceae) sur la motricite intestinale de rat

Effects of cyclohexane extract of Bidens pilosa L. on rat intestinal motility. – In vitro, we have studied the effects of the cyclohexane extract of Bidens pilosa leaves (B.p.) on the rat ileum smooth muscle motility. B.p. has showed dose-dependent stimulators effects on both tonicity and amplitude of the spontaneous contractions. With 160 ìg/mL of extract maximal stimulation wasobtained. With that dose, the rate of variation was 1027 %. Atropine reduced by 77 % the spasmogenic effects of B.p. and by 94 % the acetylcholine effects. In Ca2+ free solution, stimulation contraction by 160 ìg/mL of the extract was reduced to 400 %, while Nifedipine completely inhibited the spasmogenic effects of the extract. These results suggest that the cyclohexane extract of B.p. could stimulate ileal smooth muscle contractions through muscarinic receptors which increase Ca2+ mobilization fromboth extra- and intracellular milieu

Epidemiology of human adenoviruses: a 20-year retrospective observational study in hospitalized patients in Bern, Switzerland.

Background: Human adenovirus (HAdV) is an important pathogen seen in clinical practice. Long-term studies may help better understand epidemiological trends and changes in circulating genotypes over time. Purpose: Using a large biobank of samples from hospitalized, adenovirus-positive patients over a 20-year period, we aimed to analyze long-term epidemiological trends and genotypic relatedness among circulating HAdV strains. Methods: Based on samples from hospitalized patients confirmed to be HAdV positive in Bern, Switzerland, from 1998 to 2017, and on their associated demographic and clinical data, we identified epidemiological trends and risk factors associated with HAdV infection. HAdV genotyping was performed by PCR amplification and sequencing of the hypervariable hexon gene. The obtained sequences were phylogenetically compared with sequences from international HAdV strains. Results: HAdV was identified in 1302 samples tested. Cases of HAdV infection were reported throughout the years with no clear seasonality. Upper respiratory tract samples, conjunctivitis swabs, and stool had the highest positivity rate (56.2%, 18.7%, and 14.2% of the cases, respectively). HAdV infection was highest among children ≤4 years old. Increased number of HAdV cases were observed in years 2009 (n = 110) and 2010 (n =112). HAdV8 was the predominant genotype among patients older than 20 years, and was mostly associated with ophthalmic infection. Predominant genotypes among children ≤4 years old were HAdV1, HAdV2, and HAdV3, which were mostly associated with respiratory tract infections. Recurring peaks of increased HAdV cases were evidenced every 4 years among children ≤4 years old. Conclusion: Our study gives novel insights on long-term epidemiological trends and phylogenetic relatedness among circulating HAdV strains in Switzerland, country in which little data on HAdV prevalence and diversity was so far available

In vitro evaluation of the antimicrobial properties of Mallotus oppositifolium decoction leaf extracts and fractions

In order to verify the in vitro antimicrobial properties of Mallotus oppositifolium (Euphorbiaceae), the qualitative phytochemical screening and the antimicrobial activities on Shigella dysenteriae A2, Salmonella typhi, Escherichia coli, Enterococcus faecalis, Staphyllococcus aureus and Candida albicans strains of the aqueous decoction (DEMO) hexane (HEMO) and methanol (MEMO) fractions of leaves were assessed. The screening was performed using colorimetric methods. The antimicrobial activity was carried out using disc diffusion assays. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by the dilution methods. The screening revealed the presence of metabolites such as alkaloids, flavonoids, phenolic compounds, tannins, saponins, lipids, carbohydrates, mucilages, proteins, triterpens and steroids. DEMO, HEMO, MEMO showed a concentration-dependent activity against Shigella dysenteriae A2 and Salmonella typhi, with inhibition zone ranging from 9.44±0.44 to 19.00±0.24 mm, 8.94±0.05 to 20.03±0.17 mm and 8.13±0.17 to 16.76±0.11 mm respectively. The MIC showed ranges from 0.25 to 1.00 mg.mL-1, 0.20 to 0.50 mg.mL-1 and 1.00 to 3.00 mg.mL-1, while the MBC ranged from 1.00 to 5.00 mg.mL-1, 0.50 to 1.00 and 3.00 to 10.00 mg.mL-1 respectively. The leaves decoction and fractions activity on the two strains showed promising activities to justify the use of the plant against diarrhoea in folk medicine.Keywords: Folk medicine, phytochemical analysis, Mallotus oppositifolium diarrhea, antimicrobial

Mycobacterium ulcerans ecological dynamics and its association with freshwater ecosystems and aquatic communities : results from a 12-month environmental survey in Cameroon

Background: Mycobacterium ulcerans (MU) is the agent responsible for Buruli Ulcer (BU), an emerging skin disease with dramatic socioeconomic and health outcomes, especially in rural settings. BU emergence and distribution is linked to aquatic ecosystems in tropical and subtropical countries, especially to swampy and flooded areas. Aquatic animal organisms are likely to play a role either as host reservoirs or vectors of the bacilli. However, information on MU ecological dynamics, both in space and time, is dramatically lacking. As a result, the ecology of the disease agent, and consequently its mode of transmission, remains largely unknown, which jeopardizes public health attempts for its control. The objective of this study was to gain insight on MU environmental distribution and colonization of aquatic organisms through time. Methodology/Principal Findings: Longitudinal sampling of 32 communities of aquatic macro-invertebrates and vertebrates was conducted from different environments in two BU endemic regions in Cameroon during 12 months. As a result, 238,496 individuals were classified and MU presence was assessed by qPCR in 3,084 sample-pools containing these aquatic organisms. Our study showed a broad distribution of MU in all ecosystems and taxonomic groups, with important regional differences in its occurrence. Colonization dynamics fluctuated along the year, with the highest peaks in August and October. The large variations observed in the colonization dynamics of different taxonomic groups and aquatic ecosystems suggest that the trends shown here are the result of complex ecological processes that need further investigation. Conclusion/Perspectives: This is the largest field study on MU ecology to date, providing the first detailed description of its spatio-temporal dynamics in different aquatic ecosystems within BU endemic regions. We argue that coupling this data with fine-scale epidemiological data through statistical and mathematical models will provide a major step forward in the understanding of MU ecology and mode of transmission

Spatial distribution and insecticide resistance profile of Aedes aegypti and Aedes albopictus in Douala, the most important city of Cameroon

Prevention and control of Aedes-borne viral diseases such as dengue rely on vector control, including the use of insecticides and reduction of larval sources. However, this is threatened by the emergence of insecticide resistance. This study aimed to update the spatial distribution, the insecticide resistance profile of A. aegypti and A. albopictus and the potential resistant mechanisms implicated in the city of Douala. Immature stages of Aedes were collected in August 2020 in eight neighbourhoods in Douala and reared to adult stages. Adult bioassays, and piperonyl butoxide (PBO) synergist assays were carried out according to World Health Organization recommendations. Expression of some candidate metabolic genes including Cyp9M6F88/87, Cyp9J28a, Cyp9J10 and Cyp9J32 in A. aegypti, and Cyp6P12 in A. albopictus were assessed using qPCR. A. aegypti adults G0 were screened using real time melting curve qPCR analyses to genotype the F1534C, V1016I and V410L Aedes kdr mutations. Overall, A. aegypti is the predominant Aedes species, but analyses revealed that both A. albopictus and A. aegypti coexist in all the prospected neighbourhoods of Douala. High level of resistance was observed to three pyrethroids tested in both Aedes species. In A. aegypti a lower mortality rate was reported to permethrin (5.83%) and a higher mortality rate to deltamethrin (63.74%). Meanwhile, for A. albopictus, lower (6.72%) and higher (84.11%) mortality rates were reported to deltamethrin. Similar analysis with bendiocarb, revealed for A. aegypti a loss of susceptibility. However, in A. albopictus samples, analyses revealed a susceptibility in Logbessou, and confirmed resistance in Kotto (59.78%). A partial recovery of mortality was found to insecticides after pre-exposure to PBO. Cyp6P12 was found significantly overexpressed in A. albopictus permethrin resistant and Cyp9M6F88/87 for A. aegypti deltamethrin resistant. F1534C, V1016I and V410L mutations were detected in A. aegypti from different neighbourhoods and by considering the combination of these three kdr 14 genotypes were found. These findings provide relevant information which should be capitalised in the implementation of arbovirus vector control strategies and insecticide resistance management

Stability analysis and dynamics preserving nonstandard finite difference schemes for a malaria model

When both human and mosquito populations vary, forward bifurcation occurs if the basic reproduction number R0 is less than one in the absence of disease-induced death. When the disease-induced death rate is large enough R0 = 1 is a subcritical backward bifurcation point. The domain for the study of the dynamics is reduced to a compact and feasible region, where the system admits a speci c algebraic decomposition into infective and non-infected humans and mosquitoes. Stability results are extended and the possibility of backward bifurcation is clari ed. A dynamically consistent nonstandard nite di erence scheme is designed.Yves Dumont was supported jointly by the French Ministry of Health and the 2007–2013 Convergence program of the European Regional Development Fund (ERDF). Roumen Anguelov, Jean Lubuma, and Eunice Mureithi thank the South African National Research Foundation for its support.http://www.tandfonline.com/loi/gmps20hb201

Genetic Structure of the Tiger Mosquito, Aedes albopictus, in Cameroon (Central Africa)

Background: Aedes albopictus (Skuse, 1884) (Diptera: Culicidae), a mosquito native to Asia, has recently invaded all five continents. In Central Africa it was first reported in the early 2000s, and has since been implicated in the emergence of arboviruses such as dengue and chikungunya in this region. Recent genetic studies of invasive species have shown that multiple introductions are a key factor for successful expansion in new areas. As a result, phenotypic characters such as vector competence and insecticide susceptibility may vary within invasive pest species, potentially affecting vector efficiency and pest management. Here we assessed the genetic variability and population genetics of Ae. albopictus isolates in Cameroon (Central Africa), thereby deducing their likely geographic origin. Methods and Results: Mosquitoes were sampled in 2007 in 12 localities in southern Cameroon and analyzed for polymorphism at six microsatellite loci and in two mitochondrial DNA regions (ND5 and COI). All the microsatellite markers were successfully amplified and were polymorphic, showing moderate genetic structureamong geographic populations (F-ST = 0.068, P<0.0001). Analysis of mtDNA sequences revealed four haplotypes each for the COI and ND5 genes, with a dominant haplotype shared by all Cameroonian samples. The weak genetic variation estimated from the mtDNA genes is consistent with the recent arrival of Ae. albopictus in Cameroon. Phylogeographic analysis based on COI polymorphism indicated that Ae. albopictus populations from Cameroon are related to tropical rather than temperate or subtropical outgroups. Conclusion: The moderate genetic diversity observed among Cameroonian Ae. albopictus isolates is in keeping with recent introduction and spread in this country. The genetic structure of natural populations points to multiple introductions from tropical regions