COMPARISON OF ELECTROCOAGULATION AND CHEMICAL COAGULATION IN THE TREATMENT OF ARTISANAL TANNERY EFFLUENTS

In this study, the treatment of the effluents of an artisanal tannery by electrocoagulation with iron electrodes was carried out. During electrolytic treatment, a current intensity of 0.4 A was used, and the electrolysis time was varied from 0 to 40 minutes. The performance of electrocoagulation was compared with that of chemical coagulation with ferric sulfate. The results obtained showed that highest removals after electrocoagulation were 71.15, 98.26, and 86.59% for the COD, colour and turbidity respectively. Chemical coagulation reduced the COD up to 83.17%, while colour and turbidity removals were 99.81 and 98.62% respectively. Although chemical coagulation leads to highest percentage removals after treatment, electrocoagulation results in near neutral pH values and also decrease conductivity weakly. By contrast, chemical coagulation increases the acidity of the effluent and its conductivity. Hence with close to neutral pH and weak conductivity values obtained for effluents treated by electrocoagulation, it is inferred that such treated effluents can be recycled. http://dx.doi.org/10.4314/njt.v35i1.2

Synthesis of novel stilbene–coumarin derivatives and antifungal screening of monotes kerstingii-specialized metabolites against fusarium oxysporum

Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural productivity worldwide. Current chemical fungicides exhibit toxicity against non-target organisms, triggering negative environmental impact, and are a danger to consumers. In order to explore the chemical diversity of plants for potential antifungal applications, crude extract and fractions from Monotes kerstingii were screened for their activity against two multi-resistant Fusarium oxysporum strains: Fo32931 and Fo4287. Antifungal activity was evaluated by the determination of minimum inhibitory concentration (MIC) by broth dilution of fermentative yeasts using kinetic OD600 nm reading by a spectrophotometer. The n-butanol fraction showed the best activity against Fo4287. We screened eleven previously reported natural compounds isolated from different fractions, and a stilbene–coumarin 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-4,7-dimethoxy-3-methyl-2H-1-benzopyran-2-one (1) was the most active compound against both strains. Compound 1 was employed as a nucleophile with a selection of electrophilic derivatizing agents to synthesize five novel stilbene–coumarin analogues. These semisynthetic derivatives showed moderate activity against Fo32931 with only prenylated derivative exhibiting activity comparable to the natural stilbene–coumarin (1), demonstrating the key role of the phenolic group

Trypanocidal and leishmanicidal activity of six limonoids

Six limonoids [kotschyienone A and B (1, 2), 7-deacetylgedunin (3), 7-deacetyl-7-oxogedunin (4), andirobin (5) and methyl angolensate (6)] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major. Whereas all compounds showed anti-trypanosomal activity, only compounds 1–4 displayed anti-leishmanial activity. The 50% growth inhibition (GI 50) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.5 and 14.9 μM. Kotschyienone A (1) was found to be the most active compound with a minimal inhibition concentration (MIC) value of 10 μM and GI 50 values between 2.5 and 2.9 μM. Only compounds 1 and 3 showed moderate cytotoxicity against HL-60 cells with MIC and GI 50 values of 100 μM and 31.5–46.2 μM, respectively. Compound 1 was also found to show activity against intracellular amastigotes of L. major with a GI 50 value of 1.5 μM. The results suggest that limonoids have potential as drug candidates for the development of new treatments against trypanosomiasis and leishmaniasis

Traditional Medicine: Past, present and future research and development prospects and integration in the National Health System of Cameroon

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the  strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country.Key words: Tradttional medicine, Cameroon

Sinteza, antimikrobno i antitumorsko djelovanje nekoliko novih N-etil, N-benzil i N-benzoil-3-indolil heterocikličkih spojeva

A series of 1-(N-substituted-1H-indol-3-yl)-3-arylprop-2-ene-1-ones (2a,b-4a,b) were prepared and allowed to react with urea, thiourea or guanidine to give pyrimidine derivatives 5a,b–13a,b. Reaction of 2a,b-4a,b with ethyl acetoacetate in the presence of a base gave cyclohexanone derivatives 14a,b-16a,b. Reaction of the latter compounds with hydrazine hydrate afforded indazole derivatives 17a,b-19a,b. On the other hand, reaction of 2a,b-4a,b with some hydrazine derivatives, namely hydrazine hydrate, acetyl hydrazine, phenyl- hydrazine and benzylhydrazine hydrochloride, led to the formation of pyrazole derivatives 20a,b-31a,b. Moreover, reaction of 2a,b-4a,b with hydroxylamine hydrochloride gave isoxazole derivatives 32a,b-34a,b. The newly synthesized compounds were tested for their antimicrobial activity and showed that 4-(N-ethyl-1H-indol-3-yl)-6-(p-chlorophenyl)-pyrimidine-2-amine (11b) was the most active of all the test compounds towards Candida albicans compared to the reference drug cycloheximide. Eighteen new compounds, namely pyrimidin-2(1H)-ones 5a,b-7a,b, pyrimidin-2(1H)-thiones 8a,b-10a,b and pyrimidin-2-amines 11a,b-13a,b derivatives, were tested for their in vitro antiproliferative activity against HEPG2, MCF7 and HCT-116 cancer cell lines. 4-(N-ethyl-1H-indol-3-yl)-6-(p-methoxyphenyl)-pyrimidin-2-amine (11a) was found to be highly active with IC50 of 0.7 µmol L1.Sintetizirana je serija 1-(N-supstituiranih-1H-indol-3-il)-3-arilprop-2-en-1-ona (2a,b-4a,b) i podvrgnuta reakciji s ureom, tioureom ili gvanidinom, pri čemu su nastali derivati pirimidina 5a,b–13a,b. Reakcijom 2a,b-4a,b s etil-acetoacetatom u prisutnosti baze nastali su derivati cikloheksanona 14a,b-16a,b. Njihovom reakcijom s hidrazin hidratom dobiveni su derivati indazola 17a,b-19a,b. S druge strane, reakcijom 2a,b-4a,b s određenim derivatima hidrazina, tj. s hidrazin hidratom, acetil hidrazinom, fenilhidrazinom i benzilhidrazin hidrokloridom, nastali su derivati pirazola 20a,b-31a,b. Nadalje, reakcijom 2a,b-4a,b s hidroksilamin hidrokloridom dobiveni su derivati izoksazola 32a,b-34a,b. Pripravljeni spojevi ispitani su na antimikrobno djelovanje. Pokazalo se da je 4-(N-etil-1H-indol-3-il)-6-(p-klorfenil)-pirimidin-2-amin (11b) najaktivniji spoj za Candida albicans (ATCC 10231) uz cikloheksimid kao poredbeni lijek. Testirano je antitumorsko djelovanje in vitro osamnaest novih spojeva, tj. pirimidin-2(1H)-ona 5a,b-7a,b, pirimidin-2(1H)-tiona 8a,b-10a,b i pirimidin-2-amina 11a,b-13a,b na tumorske stanice HEPG2, MCF7 i HCT-116. Najaktivniji spoj bio je 4-(N-etil-1H-indol-3-il)-6-(p-metoksifenil)-pirimidin-2-amin (11a) uz IC50 0,7 µmol L1

TRADITIONAL MEDICINE: PAST, PRESENT AND FUTURE RESEARCH AND DEVELOPMENT PROSPECTS AND INTEGRATION IN THE NATIONAL HEALTH SYSTEM OF CAMEROON.

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country

Evaluation of removal efficiency of fluoride from aqueous solution using new charcoals that contain calcium compounds.

International audienceCharcoals that contain calcium compounds have been synthesized by impregnating wood with calcium chloride followed by carbonization at 500 degrees C, 650 degrees C or 900 degrees C. The charcoals were characterized by SEM, EDAX, XRD and chemical titrations. These adsorbents were porous with the wood microstructure. XRD revealed the presence of crystallized CaCO(3) and CaO. Despite this content, all the charcoals showed acidic surface properties and pH of point of zero charge (pH(PZC)) values were around 7.4-7.7. Their performance for fluoride removal from aqueous solution was evaluated by batch experiments. Fluoride adsorption kinetic followed a pseudo-second order model. Charcoal prepared at 650 degrees C exhibited the best efficiency with a fluoride sorption capacity of 19.05 mg g(-1) calculated from the Langmuir model. A fluoride residual concentration of 0.67 mg L(-1) was achieved within 24 h from a 10 mg L(-1) solution at neutral pH. The fluoride removal was not modified by the presence of NO(3)(-), SO(4)(2-) and PO(4)(3-) in the fluoride solution, while HCO(3)(-) and Cl(-) slightly affected the defluoridation capacity. The charcoals were chemically stable in solution and the amount of dissolved Ca was found to be 3.23 mg L(-1) at neutral pH

Effect of pH on Escherichia coli Removal by Electrocoagulation and Elimination Kinetics after Treatment

There are different techniques for removing microorganisms in wastewater, each with its own advantages and disadvantages. Electrocoagulation because of its simplicity has gained great attention and is used for the removal of various ions, organic matters, and microorganisms. In this study, the effectiveness and mechanism of Escherichia coli (E. coli) removal by electrocoagulation process using aluminum and ordinary steel electrodes at different initial-pH and the kinetics of elimination of E. coli in solution after treatment were investigated. Artificial wastewater contaminated by E. coli culture was used in the experiments. The results show that the initial-pH influences significantly the effectiveness of E. coli removal. Under the experimental conditions used, more than 5 log removal of E. coli is obtained, irrespective of the nature of the electrode (ordinary steel or aluminum) and the value of the initial pH. On the one hand, the best rates of elimination are obtained for solutions that are slightly acidic (pH 5.5) and for an alkaline pH (8.5 and 10). On the other hand, the elimination decreases for a neutral solution and for a very acidic solution (pH 2.9) because of the strong resistance developed by E. coli at those pH values. For optimal treatment, the choice of electrode material depends on the initial pH. Furthermore, the study of the kinetics of elimination of E. coli after treatment shows the remanent power of the electrocoagulation process. It allows reducing treatment time and energy consumption, thus reducing the cost of treatment