In vitro antiplasmodial activity of crude extracts from Togolese medicinal plants

Objective:To investigate the antimalarial effect of a few plants in Togo folk medicine. Methods:After ethnobotanical survey,Opilia celtidifolia,Pavetta corymbosa（P.corymbosa） and Tamarindus indica（T.indica） were selected for screening.In vitro antimalarial tests were performed on crude extracts against fresh clinical isolates of Plasmodium falciparum using the semi microtest.Results:Different IC50,values of the extracts ranged from 2.042 to 100.000μg/mL. According to the results,the methanol extract of aerial part of P.corymbosa followed by aqueous extract of fruit of T.indica were the most active(IC50 of 2.042 and 4.786μg/mL,respectively). Qualitative test revealed the presence of alkaloids in the leaves of P.corymbosa that may be responsible for the activity of the plant.Conclusions:Our study provides scientific evidence for usage of plant in the folk medicine,and further studies are needed for identification and purification of the active principles.

Epidemiology and antibiotic resistance of bacterial meningitis in Dapaong,northern Togo

Objective:To assess the seasonality of the bacterial meningitis and the antibiotic resistance of incriminated bacteria over the last three years in the northern Togo.Methods:From January 2007 to January 2010,533 cerebrospinal fluids(CSF) samples were collected from patients suspected of meningitis in the Regional Hospital of Dapaong(northern Togo).After microscopic examination,samples were cultured for bacterial identification and antibiotic susceptibility. Results:The study included 533 patients(306 male and 227 female) aged from 1 day to 55 years [average age(13.00±2.07) years].Bacterial isolation and identification were attempted for 254/533 (47.65%) samples.The bacteria]species identified were:Neisseria meningitidis A(N.meningitidis A)(58.27%),Neisseria meningitidis W135(N,meningitidis W135)(7.09%),Streptococcus pneumoniae(S.pneumoniae)(26.77%),Haemophilus influenza B(H.influenza B)(6.30%) and Enterobacteriaceae(1.57%).The results indicated that bacterial meningitis occur from November to May with a peak in February for H.influenzae and S.pneumoniae and March for Neisseriaceae. The distribution of positive CSF with regards to the age showed that subjects between 6 and 12 years followed by subjects of 0 to 5 years were most affected with respective frequencies of 67.82%and 56.52%(P【0.001).Susceptibility tests revealed that bacteria have developed resistance to several antibiotics including aminosides(resistance rate】20%for both bacterial strains),macrolides(resistance rate】30%for H.influenzae) quinolones(resistance rate】15% for H.influenzae and N.meningitidis W135).Over three years,the prevalence of S.pneumoniae significantly increased from 8.48%to 73.33%(P【0.001),while the changes in the prevalence of H.influenzae B were not statistically significant:4.24%,vs.8.89%,(P= 0.233).Conclusions: Our results indicate that data in African countries differ depending on geographical location in relation to the African meningitis belt.This underlines the importance of epidemiological surveillance of bacterial meningitis.

Antimicrobial,antiplasmodial,haemolytic and antioxidant activities of crude extracts from three selected Togolese medicinal plants

Objective:To investigate the antioxidant,antimicrobial,antiplasmodial,acute toxicity and haemolytic activities of methanolic extracts of three plants.Phytochemical analysis to determine the phenolic contents was also carried out.Methods:The 2,2-diphenyl-1- picryl-hydrazyl（DPPH） free radical scavenging,NCCLS broth microdilution and Plasmodium Lactate Dehydrogenase（pLDH） assays were used to determine antioxidant,antimicrobial and antiplasmodial activities,respectively.Haemolysis assay was conducted on A+ human red blood cells and acute toxicity on male Swiss albino mice.Phenolics were quantitatively determined using spectrophotometric methods.Results:The DPPH assay yielded interesting antioxidant activities of methanolic extract of Parinari curatellifolia（P.curatellifolia） and Entada africana （E.africana）(IC50 were 0.20±0.01μg/mL and 0.47±0.01μg/mL,respectively).This activity was highly correlated with phenolic contents of extracts.The antimicrobial tests displayed minimal inhibitory concentrations（MICs） values ranging from 0.90 to 1.80 mg/mL for Serratia marcescens （5.marcescens） the most susceptible bacterial strain.MIC value was 1.20 mg/mL for susceptible fungal strains including Mucor rouxi（M.rouxi）,Fusarium oxyporum（F.oxyporum） and Rhizopus nigricans（R.nigricans）.pLDH assay showed moderate antiplasmodial activity of Balanites aegyptiaca（B.aegyptiaca）(IC50= 24.56±3.45μg/mL),however this extract was highly haemolytic and toxic in mice(LD50= 625±128mg/kg).Conclusions:Our results support in part the use of the selected plants in the treatment of microbial infections.In addition the plant showed interesting antioxidant activity that could be useful in the management of oxidative stress.

Characterization of Self Dual Lattices in R, R₂and R₃

This paper shows that the only self dual lattices in R, R2, R3??are rotations of Z?, Z×Z?and Z×Z×Z.

Characterization of Periodic Eigenfunctions of the Fourier Transform Operator

We generalize this result to p1,p2-periodic eigenfunctions of F?on R2 and to p1,p2,p3-periodic eigenfunctions of F?on R3.