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Introduction: Siphonochilus aethiopicus is a medicinal plant widely used in the treatment of many inflammatory conditions such as arthritis. The objective of this study was therefore to evaluate the antioxidant and anti-inflammatory properties of methanolic extract of S. aethiopicus rhizomes. Methods: The total phenolic compounds, flavonoid, and tannin content, as well as the in vitro antioxidant activity of the extract, were estimated. The in vivo anti-inflammatory activity was then evaluated in male mice aged 3 to 4 months using the arthritic mouse model induced by carrageenan (0.05 ml; 1%) and monosodium urate (MSU) crystals (26.6 mg/mL). Mice were treated with the methanolic extract of S. aethiopicus (75, 150, 300 mg/kg) and the reference drugs: indomethacin (3 mg/kg) and colchicine (1 mg/kg). The serum, splenic, and hepatic lysosomal enzymes were determined, and oxidative stress biomarkers were estimated. Paws were sectioned for histological analysis. Results: Results showed that S. aethiopicus extract had non-negligible concentrations of polyphenols, flavonoids, and tannins, which could confer it an antioxidant effect. Further, the methanolic extract of S. aethiopicus at different doses significantly (P < 0.05) reduced paw swelling, attenuated joint inflammation, limited the release of lysosomal enzymes, and improved antioxidant enzymes. Conclusion: The methanolic extract of S. aethiopicus has anti-inflammatory and antioxidant properties, and can be used to treat acute forms of gouty arthritis.

Background: The resistance of gastrointestinal worms to synthetic anthelmintics (Levamisole) leads us to highlight the Cameroonian pharmacopoeia. The main objective of the present work is to look for an alternative treatment for haemonchosis, based on active secondary metabolites, from Portulaca oleracea, with less or no side effects and accessible to all. Methods: The Haemonchus contortus cycle test was performed at varying concentrations. Levamisole and PBS were the positive and negative controls respectively. Phytochemical screening was performed by standard staining and precipitation methods. Acute and sub-acute toxicity tests of Portulaca oleracea EA were performed according to OECD 425 and 407 respectively. Results: EM at 48 h of incubation inhibited eggs with an LC50 of 3.44. There was more larvicidal effect of ME with an LC50 value of 3.54 at 48 h incubation. At 24 h of incubation at the final concentration of 1000 µg/mL the anthelmintic effect of EA, ME and levamisole were noted with LC50 values of 0.057, 0.096, and 0.069 respectively. Phytochemical screening revealed the presence of some secondary metabolites in EA and ME of Portulaca oleracea. The result of the assays shows that ME is richer in total polyphenol (50.884 mg EAG/g DM) and flavonoids (5.688 mg RE/g DM) compared to EA which has (12.998 mg EAG/g DM) and (1.847 mg EC/g DM) respectively. However, there are more tannins in EA (5.688 mg RE/g DM) compared to ME (1.847 mg EC/g DM). The acute and subacute toxicity test showed no toxicity in mice and rats respectively. Conclusion: In view of the above, Portulaca oleracea possesses anthelmintic effects on the parasite Haemonchus contortus and is not toxic at the experimental therapeutic dose, which may open a way for the searching of a new anthelmintic drug. Keywords: Haemonchus contortus; Portulaca oleracea; Levamisole; Phytochemical screening; Toxicity.

Campylobacteriosis is a disease caused by the bacteria calledCampylobacterspp, it is considered a public health problem.Campylobacterspphas so far been identified as the pathogen most responsible for bacterial gastroenteritis. Emphasis was placed on controlling the foodborne route of exposure. The assessment of the actual burden ofCampylobacterin the African context, particularly in Cameroon, is hampered by the lack of reporting of diarrheal incidents and the ineffectiveness of monitoring and surveillance programs for foodborne illnesses, as well as the lack of attention given toCampylobacteras a causative agent of diarrhea for the sole benefit ofSalmonella. This article aims to report on the characterization ofCampylobactersppin infected chickens and children in Central Africa, more specifically in Cameroon.Campylobacterinfection is more prevalent in the pediatric population and has been isolated from farm animals, particularly chickens and foods of animal origin. The prevalence ofCampylobacterin children with diarrhea under five years of age ranges from 15% to 23% in Angola. In chickens, the prevalence varies from 90% in Cameroon to 41.2% in Congo. This review also highlights the increased resistance ofCampylobacterto common important antimicrobials, such as ciprofloxacin, tetracycline and erythromycin, in food animals and humans in Central Africa. The solution to limit the incidence in humans is to control and prevent the spread of pathogens in animals constituting the main reservoir of infections.

Onchocerciasis is a filarial disease caused by Onchocerca volvulus and transmitted through the bite of a blackfly of the genus Simulium. The microfilaricidal drug ivermectin has long been relied on to treat onchocerciasis. Nowadays, the focus is on the complete elimination of the disease through the development of macro-filaricidal drugs. In this study, a hydro-alcoholic extract from Annona senegalensis leaves was screened for micro- and macrofilaricidal activities against the cattle parasitic nematode Onchocerca ochengi and the free-living nematode Caenorhabditis elegans, both model organisms. Worms were assessed by in vitro motility/mortality assay studies and incubated with the various natural products and their effects on mortality were monitored after 48 h. The crude extract showed high activity with LC50 = 1450.2 µg/mL on the young adult of C. elegans wild type and 19.63 µg/mL on adult males of O. ochengi after 48 h post-exposure. The compounds, Quercetin-3-O-glucoside, (+)-Catechin, (-)-Epicatechin, Rutin and AS14.5, displayed LC50 of 179.3, 840.5, 1270.3, 118.2 and 129.7 µg/mL on C. elegans wild type (young adult), respectively, and 7.3, 17.5, 12.6, 6.6 and 11.5 µg/mL on O. ochengi (adult males), respectively, after 48 h. These data support the use of Annona senegalensis for the treatment of infections caused by Onchocerca volvulus.

Enteric campylobacteriosis caused by Campylobacter is a real public health problem. It is a typical zoonosis that can be transmitted through direct contact with contaminated animals or animal carcasses, or indirectly through the ingestion of contaminated food or water. WHO1 defines Campylobacter as the first germ responsible for gastroenteritis in developing countries. The objective of the study is to determine the prevalence of Campylobacter in pigs and to identify the most common species found in three slaughterhouses in the city of Yaounde. A descriptive and prospective study was carried out over a period of five months, from July to November 2020. To do this, Campylobacter spp. strains were searched for by culture on specific media, incubated in a micro-aerophilic atmosphere at 37°C and the identification with API campy (BioMerieux, ref 20800). Out of the 266 samples collected, 170 from the rectum and 96 from the carcasses, we obtained a general prevalence of 27%, with a prevalence of 25.88% in the rectum and 29.16% in the carcasses. Pigs intended for consumption by the population of Yaounde come mainly from the North (50%) and the West (49%). The most common species encountered were C. coli (52.77%), C. jejuni spp. jejuni 1 and 2 (30.58%), C. festus spp. festus (11.11%), C. jejuni spp. doley (1.38%), and Campylobacter spp. (4.16%). Bacterial enumeration gave Campylobacter fecal concentrations at 103 CFU2 (52.7%), 104 CFU (33.3%), and 105 CFU (13.8%). The slaughterhouse in the Mvog Ada market was the most involved in Campybacter cases, followed by the 8th market and Essos market. From the above, it is important to notice that the Campylobacter danger remains and that preventive measures are of great interest.

Campylobacter is the most frequent bacteria implicated in acute gastroenteritis in the industrialized world and is considered as a major public health problem. The aim of this review is to improve our knowledge on the bacteriological profile of Campylobacter isolated from pigs. Porks, beef also represent sources of infection with these microorganisms. Campylobacter is a bacterium comprising seventeen species, including Campylobacter jejuni, Campylobacter coli and Campylobacter fetus. C. coli is the most common Campylobacter species recovered from pigs. The prevalence (46%, 52%, 75%) varies from one country to another, from the collection site. C. jejuni and C. coli grows best in a low oxygen or microaerophilic environment. The virulence markers varies among different sources of the isolates. The majority of genes were found at high levels in Campylobacter spp. isolated from pork meat (csrA, sodB, cdtB, and racR). Moreover, this review revealed virulent properties of Campylobacter isolated from swine products and high resistance rates to Tetracycline (68%), Erythromycin (61%), which may represent difficulties in campylobacteriosis treatment. Fluoroquinolones resistance (2.2%, 7%, 11%,100%) varies according to the country and the source of the sample. It will be wise to insist on hygenic measures as a solution to limit the incidence of Campylobacter and prevent dissemination of pathogens in animals (chicken, pork and beef) within slaughter-houses/ killings Cameroon.

A phytochemical screening and in vitro anthelminthic activity of aqueous and ethanolic extract of Senna italica on Haemonchus contortus were conducted. Polyphenol, tannin and flavonoid contents were determined by using gallic acid and rutin. egg hatching inhibition test was carried out on fresh eggs; larval mortality test was conducted on infective larvae (L3) and adult worm mortality test was conducted. Eggs, larvae and adults worms were incubated in aqueous and ethanolic extract of S. italica at different concentrations (0.1; 0.3; 0.5; 0.7 and 1 mg/mL). All extracts of plants showed an effect on all stages of H. contortus with high efficiency variations depending on the dose used. The inhibition of eggs hatching rate increased from 8.67±1.53% to 65.67±1.15% and from 24.67±1.53% to 80±1.73% respectively for aqueous and ethanolic extract of S. italic. The larval mortality rate increased from 12.22±2.34% to 56.67±4.9% after 24 h and from 45.28±4.11% to 91.25±3.73% after 48 h for aqueous extract and from 30.07±2.84% to 70.83±6.31% after 24 h and from 48.79±3.73% to 96.25±4.79% after 48 h for ethanolic extract. After 24 h of exposure to aqueous and ethanolic extract of S. italica, the adult mortality rate varies from 55.56±9.62% to 83.33±9.62% for aqueous extract and from 61.11±9.62% to 88.89±9.62%.These in vitro results confirm the use of S. italica in traditional medicine.

Background The front line molecules from filarial worms and other nematodes or helminthes are their Excretory-Secretory (ES) products. Their interaction with the host cells, proteins and immune system accounts for the skin and eye pathology or hyposensitivity observed in human onchocerciasis. ES products and adult worms’ crude extracts from Onchocerca ochengi, a filarial nematode that infects the African zebu cattle, were utilized in the present study as a model for studying Onchocerca volvulus that causes river blindness in man. Methods The ES products were generated from adult male and female worms in vitro and analyzed with poly acrylamide gel electrophoresis (PAGE) and enzyme-linked immunosorbent assay (ELISA) using sera from Onchocerca-infected cattle and humans. The cattle sera were collected from a herd that had been exposed for six years to natural transmission of Onchocerca spp. The expressed reactivity was evaluated and differences analyzed statistically using Kruskal-Wallis rank and Chi-square tests. Results The gel electrophoretic analyses of 156 ES products from O. ochengi female and male worms and of two somatic extracts from three females and 25 males revealed differences in the protein pattern showing pronounced bands at 15, 30–50 and 75 kDa for male ES proteins and 15, 25 and 40–75 kDa for somatic extracts, respectively and less than 100 kDa for female worms. Proteins in the ES products and somatic extracts from female and male Onchocerca ochengi worms were recognized by IgG in sera from both Onchocerca-exposed cattle and humans. Bovine serum antibodies reacted more strongly with proteins in the somatic extracts than with those in the ES products. Interestingly, the reaction was higher with male ES products than with ES products from female worms, suggesting that the males which migrate from one nodule to another are more exposed to the host immune system than the females which remain encapsulated in intradermal nodules. Conclusions This study demonstrates that O. ochengi ES products and, in particular, extracts from male filariae may represent a good source of immunogenic proteins and potential vaccine candidates.

One of the strategies for developing novel pharmaceutical drugs is to use natural sources such as plants for therapeutic treatment. Plant extracts are a cocktail of compounds which act synergically and can improve treatment effectiveness, reduce therapeutic duration and resistance. The ethanolic extracts of leaves and seeds of Cucurbita pepo ovifera var ovifera from Sudano-Guinean and Sudano-Sahelian zones of Cameroon were evaluated on the cattle parasite nematode Onchocerca ochengi. Worms were incubated with different concentrations of the plant extracts in RPMI-1640 supplemented with streptomycin and gentamicin. Mortality at 37°C was monitored after 24, 48 and 72 h. Ivermectin was used as positive control and DMSO as negative. Plant extracts from the two ecological zones showed anthelminthic activities on O. ochengi after 72 h with LC50 varying from 20 to 1090 µg /mL. The highest antifilarial activity in Sudano-Guinean zone was obtained with leave extract of C. pepo ovifera (LC50 of 20 µg/mL), while highest antifilarial activity in Sudano-Sahelian zone was obtained with seed extracts of the plant with LC50 value of 17 µg/mL after 72 h. These results show that anthelmintic activity depends on the part of the plant and the ecological zones. Additionally, the plant is not toxic. These results on the ethanolic extracts of leaves and seeds of C. pepo ovifera var ovifera confirmed the use of this plant in traditional medicine in Cameroon to treat disease due to nematodes. The plants could be used as alternative anthelmintic to fight against Human and Bovine onchocerciasis.

Background African animal trypanosomosis remains the major constraint of livestock production and livelihood of pastoral communities in Cameroon. Despite several decades of vector and parasite control efforts, it has not been eradicated. Alternative and sustainable control strategies require a sound knowledge of the local species, strains and vectors. In the Sudano-Sahelian and Guinea Savannah of Cameroon the prevalence and genetic diversity of trypanosomes infecting cattle was investigated by microscopy of cattle blood buffy coat and molecular methods using generic primers targeting parts of the internal transcribed spacer 1 (ITS-1) and encoded glycosomal glyceraldehyde 3-phosphate dehydrogenase-gene (gGAPDH). Results A total of 1176 randomly chosen cattle from five divisions in the Sudano-Sahelian and Guinea Savannah of Cameroon were examined. The overall prevalence of trypanosomes by microscopy was 5.9% (56/953) in contrast to 53.2% (626/1176) when molecular tools were used. This indicated a limited sensitivity of microscopy in subclinical infections with frequently low parasitemia. Three trypanosome species were identified by light microscopy: T. vivax (2.3%), T. brucei (3.7%) and T. congolense (3.0%), whereas five were identified by PCR, namely T. grayi/T. theileri (30.8%), T. vivax (17.7%), T. brucei (14.5%) and T. congolense (5.1%). Unexpected cases of T. grayi (n = 4) and T. theileri (n = 26) were confirmed by sequencing. Phylogenetic analysis of the gGAPDH revealed the presence of T. vivax, clade A and T. vivax clade C, which were co-endemic in the Faro et Deo division. T. grayi/T. theileri were the predominant species infecting cattle in tsetse free areas. In contrast, T. vivax, T. brucei and T. congolense were more abundant in areas where the Glossina-vectors were present. Conclusions The abundance of pathogenic trypanosomes in tsetse infested areas is alarming and even more, the occurrence of T. vivax, T. brucei, T. congolense, T. theileri and T. grayi in tsetse-free areas implies that tsetse control alone is not sufficient to control trypanosomosis in livestock. To implement control measures that reduce the risk of spread in tsetse free areas, close monitoring using molecular tools and a thorough search for alternative vectors of trypanosomes is recommended.

During the last two decades research on animal filarial parasites, especially Onchocerca ochengi, infecting cattle in savanna areas of Africa revealed that O. ochengi as an animal model has biological features that are similar to those of O. volvulus, the aetiological agent of human onchocerciasis. There is, however, a paucity of biochemical, immunological and pathological data for O. ochengi. Galectins can be generated by parasites and their hosts. They are multifunctional molecules affecting the interaction between filarial parasites and their mammalian hosts including immune responses. This study characterized O. ochengi galectin, verified its immunologenicity and established its immune reactivity and that of Onchocerca volvulus galectin. The phylogenetic analysis showed the high degree of identity between the identified O. ochengi and the O. volvulus galectin-1 (s-galactoside-binding protein-1) consisting only in one exchange of alanine for serine. O. ochengi galectin induced IgG antibodies during 28 days after immunization of Wistar rats. IgG from O. ochengi-infected cattle and O. volvulus-infected humans cross-reacted with the corresponding galectins. Under the applied experimental conditions in a cell proliferation test, O. ochengi galectin failed to significantly stimulate peripheral blood mononuclear cells (PBMCs) from O. ochengi-infected cattle, regardless of their parasite load. An O. ochengi galectin gene was identified and the recombinantly expressed protein was immunogenic. IgG from Onchocerca-infected humans and cattle showed similar cross-reaction with both respective galectins. The present findings reflect the phylogenetic relationship between the two parasites and endorse the appropriateness of the cattle O. ochengi model for O. volvulus infection research.

Medicinal plants have been of great importance to many traditional communities for many generations. However, there is need to carry out scientific studies in order to confirm the medicinal properties of many plants used traditionally. Cosmos sulphureus (Asteraceae) used by local communities for the treatment of various diseases has showed antioxidant, antibacterial, antifungal and antiplasmodial properties although there are no studies demonstrating its antionchocerca activity. The present study was undertaken to investigate the antionchocerca potential of crude extracts and chromatographic fractions of C. sulphureus using Onchocerca ochengi, a bovine filarial closest in phylogeny to Onchocerca volvulus. Solvent extraction of the parts of C. sulphureus was performed using distilled water, 70% EtOH, MeOH, CH2Cl2 and a mixture of MeOH/CH2Cl2 (v/v). Anthelmintic assay was evaluated on adult worms of O. ochengi and worm viability was assessed biochemically using the dimethylthiazol (MTT) formazan assay. Acute and sub-acute oral toxicities of the promising extract was investigated in mice. The chemical composition of extracts was revealed. EtOH extract of roots showed highest anthelmintic activity with an LC50 value of 31.01±1.17 μg/mL which was more significant than the one of ivermectin (LC50=42.78 μg/mL) used as standard. The other extracts show moderate activities. The most active fraction obtained from EtOH extract of roots had an LC50 value of 19.10 μg/mL on male worm. For acute toxicity, a single dose of 2000 mg/kg used induced no critical behavioral changes or death. In sub- acute toxicity, daily oral administration of hydro-ethanolic extracts of roots at the dose of 250, 500 and 750 mg/kg revealed disturbances in the normal growth of animals as well as liver and kidney alterations. These results unfold potential sources of novel anti-onchocerca lead compounds and validate the traditional use of the plants in onchocerciasis treatment.

Rubella is an acute and contagious viral infection whose gravidity resides in infection during pregnancy, which can result in miscarriage, fetal death, stillbirth, or infants with congenital malformations. This study aimed to describe the genome of rubella viruses (RUBVs) circulating in Cameroon. Throat swabs were collected from health districts as part of the measles surveillance program from 2010 to 2016 and sent to the Centre Pasteur of Cameroon. Samples were amplified by genotyping reverse transcription polymerase chain reaction (RT-PCR) in the search of two overlapping fragments of the gene that encodes the E1 envelope glycoprotein of RUBV. PCR products were sequenced and phylogenetic analysis was performed with MEGA 6 software. Overall, 9 of 43 samples (20.93%) were successfully amplified and sequenced but only eight sequences could be exploited for phylogenetic analysis with respect to the required fragment length of 739 nucleotides. Analysis of viral sequences from Cameroon with other epidemiologically relevant sequences from around the world showed that all RUBVs belonged to lineage L1 of genotype 1G. Cameroon sequences clustered with viruses from West Africa including Nigeria, Ivory Coast, and Ghana with a percentage similarity of 95.4% to 99.2%. This study will enable an update on the molecular epidemiology of RUBV in Cameroon and help in monitoring circulating RUBV for a better implementation of elimination strategies.

Onchocerciasis is a filarial vector borne disease which affects several million people mostly in Africa. The therapeutic approach of its control was based on a succession of drugs which always showed limits. The last one: ivermectin is not the least. It was shown to be only microfilaricidal and induced resistance to the human parasite Onchocerca volvulus. The approach using medicinal plants used in traditional medicine is a possible alternative method to cure onchocerciasis. Onchocerca ochengi and Onchocerca gutturosa are the parasite models used to assess anthelmintic activity of potentially anthelmintic plants. Numerous studies assessed the in vitro and/or in vivo anthelmintic activity of medicinal plants. Online electronic databases were consulted to gather publications on in vitro and in vivo studies of anti-Onchocerca activity of plants from 1990 to 2017. Globally, 13 plant families were investigated for anti-Onchocerca activity in 13 studies. The most active species were Anacardium occidentale, Euphorbia hirta and Acacia nilotica each with an LC50 value of 2.76, 6.25 and 1.2 μg/mL, respectively. Polycarpol, voacamine, voacangine, ellagic acid, gallic acid, gentisic acid, 3-O-acetyl aleuritolic acid and (−)-epigallocatechin 3-O-gallate were the isolated plant compounds with anti-Onchocerca activity. Most of the assessed extract/compounds showed a good safety after in vivo acute toxicity assays and/or in vitro cytotoxicity test. The exception was the ethanol extract of Trichilia emetica, which killed completely and drastically mice at a dose of 3000 mg/kg. Several plant groups of compounds were shown active against Onchocerca sp. such as tannins, alkaloids, triterpenoids and essential oils. Nevertheless, none of the active compounds was subjected to clinical trial, to assessment of its diffusibility through nodular wall or its capability to induce genetic resistance of Onchocerca sp.

Background Botanicals are generally assumed to be more biodegradable, leading to less environmental problems. Combination of botanicals could enhance biological activity against insect pests. Hence, the amount of botanical used for the control of stored grain pests may be minimised. In this study, the bioassay was carried out on Sitophilus zeamais to assess the effectiveness of binary combinations of Hymenocardia acida wood ash and Plectranthus glandulosus leaf powder. The quantities of mixed products were added to maize grains to constitute the contents of 5, 10, 20 and 40 g/kg. Then, the bioassays on toxicity within 1, 3, 7 and 14 days exposure, progeny production, population increase, grain damage and germination ability of protected grains were carried out. Results The major compounds (pinene, α-pinene, α-terpineol, thymol, β-myrcene and 3-carene) of P. glandulosus leaf powder were monoterpenes. The major non-monoterpenic constituent was an oxygenated sesquiterpene, β caryophyllene oxide. The chemical analysis of H. acida ash showed that calcium (5800 mg/kg) and phosphorus (2782 mg/kg) recorded higher content than the other minerals. Plectranthus glandulosus leaf powder, H. acida wood ash and their binary combinations significantly induced mortality of S. zeamais adult (P

Background Onchocerciasis is one of the tropical neglected diseases (NTDs) caused by the nematode Onchocerca volvulus. Control strategies currently in use rely on mass administration of ivermectin, which has marked activity against microfilariae. Furthermore, the development of resistance to ivermectin was observed. Since vaccine and safe macrofilaricidal treatment against onchocerciasis are still lacking, there is an urgent need to discover novel drugs. This study was undertaken to investigate the anthelmintic activity of Lophira lanceolata on the cattle parasite Onchocerca ochengi and the anthelmintic drug resistant strains of the free living nematode Caenorhabditis elegans and to determine the phytochemical profiles of the extracts and fractions of the plants. Methods Plant was extracted in ethanol or methanol-methylene chloride. O. ochengi, C. elegans wild-type and C. elegans drug resistant strains were cultured in RPMI-1640 and NGM-agar respectively. Drugs diluted in dimethylsulphoxide/RPMI or M9-Buffer were added in assays and monitored at 48 h and 72 h. Worm viability was determined by using the MTT/formazan colorimetric method. Polyphenol, tannin and flavonoid contents were determined by dosage of gallic acid and rutin. Acute oral toxicity was evaluated using Swiss albino mice. Results Ethanolic and methanolic-methylene chloride extracts killed O. ochengi with LC50 values of 9.76, 8.05, 6.39 μg/mL and 9.45, 7.95, 6.39 μg/mL respectively for leaves, trunk bark and root bark after 72 h. The lowest concentrations required to kill 50% of the wild-type of C. elegans were 1200 and 1890 μg/mL with ethanolic crude extract, 1000 and 2030 μg/mL with MeOH-CH2Cl2 for root bark and trunk bark of L. lanceolata, respectively after 72 h. Leave extracts of L. lanceolata are lethal to albendazole and ivermectin resistant strains of C. elegans after 72 h. Methanol/methylene chloride extracted more metabolites. Additionally, extracts could be considered relatively safe. Conclusion Ethanolic and methanolic-methylene chloride crude extracts and fractions of L. lanceolata showed in vitro anthelmintic activity. The extracts and fractions contained polyphenols, tannins, flavonoids and saponins. The mechanism of action of this plant could be different from that of albendazole and ivermectin. These results confirm the use of L. lanceolata by traditional healers for the treatment of worm infections. Electronic supplementary material The online version of this article (doi:10.1186/s12906-017-1904-z) contains supplementary material, which is available to authorized users.

Acacia nilotica fruits with high tannin content are used in the northern parts of Cameroon as anti-filarial remedies by traditional healers. In this study, the hydro-alcoholic fruit extract (crude extract (CE)) and, one of the main constituents in its most active fractions, (+)-catechin-3-O-gallate (CG), as well as four related proanthocyanidins, (−)-epicatechin-3-O-gallate (ECG), (+)-gallocatechin (GC), (−)-epigallocatechin (EGC) and (−)-epigallocatechin-3-O-gallate (EGCG), were assessed for their potential in vitro anthelmintic properties against the free-living model organism Caenorhabditis elegans and against the cattle filarial parasite Onchocerca ochengi. Worms were incubated in the presence of different concentrations of fruit extract, fractions and pure compounds. The effects on mortality were monitored after 48 h. The plant extract and all of the pure tested compounds were active against O. ochengi (LC50 ranging from 1.2 to 11.5 µg/mL on males) and C. elegans (LC50 ranging from 33.8 to 350 µg/mL on wild type). While high LC50 were required for the effects of the compounds on C. elegans, very low LC50 were required against O. ochengi. Importantly, tests for acute oral toxicity (lowest dose: 10 mg/kg) in Wistar rats demonstrated that crude extract and pure compounds were non-toxic and safe to use. Additionally, the results of cytotoxicity tests with the Caco-2 cell line (CC50 ranging from 47.1 to 93.2 µg/mL) confirmed the absence of significant toxicity of the crude extract and pure compounds. These results are in good accordance with the use of A. nilotica against nematode infections by traditional healers, herdsmen and pastoralists in Cameroon.

Onchocerca volvulusis a tissue-dwelling, vector-borne nematode parasite of humans and is the causative agent of onchocerciasis or river blindness. Natural infections of BALB/c mice withLitomosoides sigmodontisand of cattle withOnchocerca ochengiwere used as models to study the immune responses toO. volvulus-derived recombinant proteins (OvALT-2,OvNLT-1,Ov103 andOv7). The humoral immune response ofO. volvulus-infected humans againstOvALT-2,OvNLT-1 andOv7 revealed pronounced immunoglobulin G (IgG) titres which were, however, significantly lower than against the lysate ofO. volvulusadult female worms. Sera derived from patients displaying the hyperreactive form of onchocerciasis showed a uniform trend of higher IgG reactivity both to the single proteins and theO. volvuluslysate. Sera derived fromL. sigmodontis-infected mice and from calves exposed toO. ochengitransmission in a hyperendemic area also contained IgM and IgG1 specific forO. volvulus-derived recombinant proteins. These results strongly suggest thatL. sigmodontis-specific andO. ochengi-specific immunoglobulins elicited during natural infection of mice and cattle cross-reacted withO. volvulus-derived recombinant antigens. MonitoringO. ochengi-infected calves over a 26-month period, provided a comprehensive kinetic of the humoral response to infection that was strictly correlated with parasite load and occurrence of microfilariae.

Syzygium guineense var. macrocarpum est une plante a usages multiples, a plusieurs sous-varietes et qui est menacee de disparition. Cette etude envisage de determiner le savoir endogene, de decrire et d’evaluer les sous-varietes de la plante dans les Hautes Savanes Guineennes (Adamaoua, Cameroun). Les methodes ethnobotaniques dont la valeur d’usage ethnobotanique (VUE) ont ete utilisees sur 195 hommes et 23 femmes. Les resultats ont montre de nombreux usages faits des parties de la plante. Les fruits faisaient l’unanimite en consommation humaine. L’huile issue des graines des fruits etait comestible et commercialisee. Le savoir locale dependait de l’âge, du genre et du groupe ethnolinguistique. La VUE a permis de classer les quatre sous-varietes de la plante, distinguables par leurs fruits en maturite complete en fonction des preferences. L’existence des sousvarietes indique une variabilite morphologique de Syzygium guineense var. macrocarpum dans la zone d’etude. Des etudes moleculaires pourront elucider cette variabilite. Des etudes de toxicites de l’huile issue des graines de la plante permettront sa valorisation. © 2018 International Formulae Group. All rights reserved. Mots cles: Ressources genetiques forestieres, erosion genetique, securite alimentaire, connaissance traditionnelle, Cameroun English Title: Ethnobotanical study of Syzygium guineense (Will.) DC. var. macrocarpum (Engl.) F. White sub-varieties from the Guinean Savannah Highlands (Adamawa, Cameroon) English Abstract The multipurpose tree Syzygium guineense var. macrocarpum has sub-varieties but it is at risk of disappearing. The study aimed at determining indigenous knowledge, describing and evaluating the sub-varieties of the plant from Guinean Savannah Highlands (Adamawa, Cameroon). The ethnobotanical methods as the ethno-botanic use value (UV) were used to interview 195 men and 23 women. The results showed many uses of the plant. The fruits were consumed by all the indigenous. By product seed oil from these fruits was commercialized and eaten. The indigenous knowledge was depended on age, gender and ethnolinguistic group. The four plant sub-varieties were classified using the UV depending on the preferences, discrimination among these sub-varieties were done by mature fruits characteristics. Due to existence of sub-varieties, Syzygium guineense var. macrocarpum have the morphological variability in the study area. The molecular studies are required to elucidate this variability. Studies of toxicities of the plant seed oil will make it possible to value it. © 2018 International Formulae Group. All rights reserved. Keywords: Forest genetic resources, genetic erosion, food security, indigenous knowledge, Cameroon

In eukaryotes, the key player in polyamine metabolism is the ornithine decarboxylase (ODC) that catalyses the first and rate limiting step in cellular polyamine synthesis. The half life of ODC is strictly regulated by the antizyme (AZ), which promotes its degradation. Older reports on the polyamine situation in filarial parasites indicate a lack of ornithine decarboxylation activity and an increased uptake of polyamines. Our in silico analysis of the Brugia malayi genome revealed only an ODC-like protein that lacks essential residues. Consequently, the recombinant protein had no enzymatic ODC activity. Furthermore, only ODC-like genes were found in the available draft genomes of other filarial parasites. In this ODC-free scenario, we set out to investigate the AZ of O. volvulus (OvAZ). The expression of the recombinant protein allowed us to analyse the localization of OvAZ in different O. volvulus stages as well as to identify it as target for the human humoral immune response. Strong immunostaining was observed in the outer zone of the uterine epithelium as well as in the uterus lumen around the periphery of the developing parasite, indicating a potential role of the OvAZ in the control of polyamine levels during embryonic development. By employing a novel in vivo method using Caenorhabditis elegans, we postulate that the OvAZ enters the secretory pathway. Even though the ODCs are absent in filarial parasites, OvAZ has the ability to bind to various ODCs, thereby demonstrating the functionality of the conserved AZ-binding domains. Finally, pull-down assays show an interaction between B. malayi AZ and the B. malayi ODC-like protein, indicating that the B. malayi ODC-like protein might function as an AZI. Taken together, our results suggest that filarial species do not possess the ODC while retaining the ODC-regulatory proteins AZ and AZI. It is tempting to speculate that both proteins are retained for the regulation of polyamine transport systems.

Infectious diseases caused by parasites are a major threat for the entire mankind, especially in the tropics. More than 1 billion people world-wide are directly exposed to tropical parasites such as the causative agents of trypanosomiasis, leishmaniasis, schistosomiasis, lymphatic filariasis and onchocerciasis, which represent a major health problem, particularly in impecunious areas. Unlike most antibiotics, there is no "general" antiparasitic drug available. Here, the selection of antiparasitic drugs varies between different organisms. Some of the currently available drugs are chemically de novo synthesized, however, the majority of drugs are derived from natural sources such as plants which have subsequently been chemically modified to warrant higher potency against these human pathogens. In this review article we will provide an overview of the current status of plant derived pharmaceuticals and their chemical modifications to target parasite-specific peculiarities in order to interfere with their proliferation in the human host.

Onchocerca volvulus is a human pathogenic filarial nematode causing chronic onchocerciasis, a disease characterized by chronic skin and eye lesions. Despite attempts to control this infection from many perspectives, it still remains a threat to public health because of adverse effects of available drugs and recent reports of drug resistance. Under control of an intact immune system, O. volvulus survives for a long time in the host by employing a variety of strategies including the utility of antioxidant enzymes. In the present study, we focus on the extracellular superoxide dismutase from O. volvulus (OvEC-SOD) found in the excretory/secretory products of adult worms. Contrary to previous studies, the OvEC-SOD was found to have a 19 amino acid long signal peptide that is cleaved off during the process of maturation. To validate this result, we designed a novel method based on Caenorhabditis elegans cup5(ar465) mutants to specifically evaluate signal peptide-mediated secretion of nematodal proteins. Following purification, the recombinant OvEC-SOD was active as a dimer. Site-directed mutagenesis of the three cysteines present in the OvEC-SOD shows that enzyme activity is markedly reduced in the Cys-192 mutant. A homology model of the OvEC-SOD underlines the importance of Cys-192 for the stabilization of the adjacent active site channel. The generation of a humoral immune response to secretory OvEC-SOD was indicated by demonstrating IgG reactivity in sera from patients infected with O. volvulus while the cross-reactivity of IgG in plasma samples from cows, infected with the most closely related parasite Onchocerca ochengi, occurred only marginally. High IgG1 and IgM titres were recorded in sera from mice infected with the filaria Litomosoides sigmodontis, however, low or no cellular proliferative responses were observed. Thus, the present data suggest that secretory OvEC-SOD is a target of the humoral immune response in human onchocerciasis and induced strongest IgG responses in hyperreactive onchocerciasis. Furthermore, humoral response during murine infection induced SOD-specific IgG that cross-reacted with OvEC-SOD.

Objective: To investigate the phytochemical constituents, antioxidant and anthelmintic activities of the crude methanol extract of Cissus populnea (C. populnea) rhizomes. Methods: Phytochemical screening was performed using standard protocols, and column chromatography of silica gel was used for the compounds isolation. DPPH antiradical scavenging assay was performed in order to evaluate the antioxidant activity. Total phenolic content was evaluated using the Folin–Ciocalteu assay. The anthelmintic activity was screened on the bovine adult male forms of parasitic nematode Onchocerca ochengi, by the in vitro evaluation of the inhibition of adult worm motility and mortality. Worms were incubated in the presence of different concentrations of the plant extract and effects on survival were monitored after 24 and 48 h. Results: The preliminary phytochemical screening revealed the presence of phenolic compounds, saponins, steroids, tannins, and terpenoids. Bergenin and a mixture of phytosterol, β -sitosterol and stigmasterol were isolated from this extract and were identified by nuclear magnetic resonance, mass spectrometry and by comparison with published data. The crude methanol extract of C. populnea rhizomes showed a strong DPPH antiradical activity with a good amount of total phenolic content ((20.69±2.13) g gallic acid equivalent/100 g of extract) and significant anthelmintic activity comparable to the standard drug ivermectin. Bergenin was found to be inactive even after 72 h of incubation. Conclusions: This study constitutes the first report on the anthelmintic activity of this plant and supports the traditional use of C. populnea as a natural antioxidant and anthelmintic.