Maurice BODA

Post-vaccine surveillance of Group A Rotavirus strains circulating in the Littoral and South West Regions of Cameroon

Carine Ngah Enjeh, Rahinatou N. Ghapoutsa, Maurice Boda, Mathew D. Esona, Julius M. Nwobegahay, Valantine N. Ndze et 3 autre(s)

BMC Infectious Diseases

The effectiveness of Group A Rotavirus (RVA) vaccine in low-income countries remains limited, partly due to the circulation of strains not covered by existing vaccines. Despite the introduction of Rotarix (2014) in Cameroon, no nationwide studies have comprehensively characterized circulating RVA strains. This study provides post-vaccination genotyping data of RVA strains from Douala, Edéa, Nkongsamba (Littoral Region) and Kumba (Southwest region) in Cameroon. A cross-sectional study was conducted on 197 diarrhoeal samples collected from children under five years of age along with their vaccination data from the Littoral region ( n = 130; May 2015 - April 2016) and Kumba in the Southwest Region ( n = 67; July 2017 - June 2018). RVA NSP3 gene was detected using qRT-PCR and NSP3-positive samples were further analyzed using one-step multiplex RT-PCR for genotyping of wild-type and vaccine strains, with VP4 and VP7 typing performed using nested PCR. Of the 197 children enrolled in this study, 63% were fully vaccinated with Rotarix, 22% were unvaccinated, and 15% had unknown vaccination status. Overall, 87 samples were genotyped including 28 (21.5%) from Littoral region and 59 (88.1%) from Kumba, indicating a marked difference in genotyping success across sites. Five VP7 (G) genotypes (G1, G2, G3, G9, G12) were identified with distinct regional patterns. In the Littoral region, G2 (46.4%) and G3 (35.7%) predominated whereas Kumba was dominated by G1 (61.0%) and G12 (37.3%). VP4 (P) genotypes included P [8], P [6], and P [4], with P [8] being the most prevalent in both regions. The Littoral region showed higher genotype diversity with multiple co-circulating strains, particularly G3P [8] and G2P [4] while Kumba showed a more restricted genotypic profile, dominated by G1P [8] (57.6%) and G12P [6] (32.8%). The presence of mixed infections (3.6%) and non-typeable strains (7.1%) further highlight the co-circulation of multiple strains and the potential for reassortment events. This study contributes to the limited available post-vaccination description of circulating rotavirus A (RVA) genotypes in the Littoral region and Kumba, Cameroon. Distinct patterns of genotype distribution were observed between the two study areas. In Kumba, G1P [8] and G12P [6] were the predominant genotypes, whereas a wider range of RVA genotypes was detected in the Littoral region. G1P [8] was identified among vaccinated children in both study areas, indicating its continued circulation following vaccine introduction. No statistically significant associations were found between RVA genotype distribution and sex, age, or vaccination status. Overall, the detection of both predominant and less frequently identified RVA genotypes in the post-vaccination period highlights the need for continued molecular surveillance to monitor changes in genotype distribution and evaluate the long-term impact of rotavirus vaccination in Cameroon.

• #viral gastroenteritis research and epidemiology
• #viral infections and outbreaks research
• #respiratory viral infections research
• #genotyping

Post-vaccine surveillance of Group A Rotavirus Strains circulating in the Littoral and South West Regions of Cameroon

Carine Ngah Enjeh, Rahinatou N. Ghapoutsa, Maurice Boda, Mathew D. Esona, Julius M. Nwobegahay, Valantine Ngum Ndze et 3 autre(s)

Research Square

• #viral gastroenteritis research and epidemiology
• #viral infections and outbreaks research
• #zoonotic diseases and public health
• #genotyping

Serological And Cytokine Profiling of Umbilical Cord Blood for Maternal Torch Infections: A Cross-Sectional Study on Neonatal Risk in Yaoundé, Cameroon

Sabine Aimée Touangnou-Chamda, Jacky Njiki Bikoï, Palmer Masumbe Netongo, Carole Stéphanie Sake, Veronique Mboua Batoum, Alexandra Emmanuelle Membangbi et 6 autre(s)

British journal of healthcare and medical research

Background: Umbilical cord blood (UCB) represents a valuable biological matrix for assessing neonatal exposure to maternal infections and immune status at birth. In resource-limited settings such as Cameroon, its diagnostic potential remains underutilized, particularly for the detection of vertically transmitted infections within the TORCH complex ˗ Toxoplasma gondii, Rubella virus (Rubivirus rubellae), Cytomegalovirus (CMV)/ Human Herpesvirus 5 (HHV-5), and Herpes Simplex Virus types 1 and 2 (HSV-1/2). Objectives: This study aimed to determine the seroprevalence of TORCH infections in maternal venous blood and UCB, and to compare cytokine profiles in order to characterize neonatal immune activation at birth. Methods: A cross-sectional study was conducted from June to December 2024 across two referral hospitals in Yaoundé, Cameroon. A total of 108 mother-newborn pairs were enrolled consecutively. Paired maternal venous blood and UCB samples were tested using EVANCARE IgM/IgG TORCH rapid diagnostic tests (RDT), and ELISA-based ProcartaPlex™ multiplex cytokine profiling (12 analytes). Results: TORCH seroprevalence in UCB reflected maternal infection status, with high concordance for Toxoplasma gondii (90.0%; maternal 77.5% vs. UCB 72.5%) and CMV (70.0%; maternal 55.0% vs. UCB 50.0%). Cytokine profiling revealed that 10 of 12 analytes differed between compartments; IL-6 was significantly higher in maternal plasma (33.94 vs. 25.01 pg/mL; p < 0.0001) while IL-2 was significantly elevated in UCB (17.43 vs. 16.54 pg/mL; p = 0.04), with IL-4 and IL-5 showing identical values across both compartments. Conclusion: Maternal TORCH infections exert a measurable burden on neonatal infectious and immunological status at birth. UCB represents a non-invasive and ethically advantageous specimen for neonatal assessment. These findings support the integration of TORCH screening and UCB cytokine analysis into routine antenatal care protocols in low-resource settings to reduce neonatal morbidity.

• #cytomegalovirus and herpesvirus research
• #parvovirus b19 infection studies
• #pregnancy and preeclampsia studies
• #seroprevalence

Successful Inactivation of High-Consequence Pathogens in PrimeStore Molecular Transport Media

Briana Spruill-Harrell, Gregory Kocher, Maurice Boda, Kristen Akers, Denise Freeburger, Nick M. Murphy et 5 autre(s)

Viruses

Handling cultured isolates and clinical, environmental, or wildlife surveillance samples containing Risk Group 3 and 4 pathogens presents considerable biosafety challenges in minimizing human exposure during processing and transport. Safe handling typically requires high- or maximum-containment facilities, demanding substantial logistical planning and resources. We evaluated PrimeStore Molecular Transport Medium (PS-MTM), a guanidine-based solution created to kill pathogens and preserve nucleic acids at ambient temperatures, for inactivating Crimean-Congo hemorrhagic fever, eastern equine encephalitis, Ebola, Hendra, Japanese encephalitis, Lassa, Marburg, Nipah, Rift Valley fever, and West Nile viruses. To mimic diagnostic conditions, human whole blood spiked with any of these viruses was incubated with PS-MTM for 20-, 30-, or 60-min. Samples with titers up to 107 PFU/mL exposed to PS-MTM at all time points resulted in complete loss of infectivity judged by plaque assays. A 30-min incubation provided a 50% safety margin over the minimum inactivation time and was used for quantification with the tissue culture infectious dose (TCID50) assay, enabling evaluation of PS-MTM’s activity for viruses that do or do not produce well-defined plaques. Results confirmed that PS-MTM inactivated all tested viruses at titers up to 107 TCID50/mL, underscoring its reliability for enhancing biosafety in diagnostics, outbreak management, and surveillance.

• #viral infections and outbreaks research
• #viral infections and vectors
• #mosquito-borne diseases and control
• #infectivity

Epidemiology of group A rotavirus in children under five years of age with gastroenteritis in N’Djamena, Chad

Bertrand Djikoloum, Mahamat Fayiz Abakar, Valentine Ngum Ndze, Rahinatou Ghapoutsa Nkandi, Carine Ngah Enjeh, Pidou Kimala et 2 autre(s)

BMC Infectious Diseases

BACKGROUND: Group A Rotaviruses (RVA) is one of the most common causes of severe diarrhoea in infants and children under 5 years of age. Unlike many countries in the world where RVA surveillance/control is active, in Chad , there is currently no applied RVA immunization program and surveillance strategy. The present study aims to determine the prevalence and associated risk factors of RVA gastroenteritis among children under five years of age in N'Djamena. METHOD: This study comprised two parts: (1) A cross-sectional study carried in four hospitals in N'Djamena between August and November 2019, to determine infection risk factors and evidence of RVA infection among children aged five and below, consulted or hospitalized for diarrhea. An ELISA based RVA VP6 protein detection was used to determine RVA infection prevalence. Infection results and sociodemographic data were statistically analysed to determine RVA infection risk factors. (2) A retrospective study that consisted of analysing the records of stool examinations of the period from January 2016 to December 2018, to determine the prevalence of infectious gastroenteritis among the target population. RESULTS: For the cross-sectional study, RVA infection prevalence was 12.76% (18/141) with males (61.11%) being more affected (sex ratio: 1.57). Children below 12 months were the most affected age group (44.44%) and 44.4% were malnourished. The mean Vesikari score shows that 38.8% of children have a high severity level and 41.1% have a moderate level. For the retrospective study, 2,592 cases of gastroenteritis hospitalization were analysed; 980 out of 2,592 cases (37.81%) of hospitalization due to diarrhoea were due to diarrhoeagenic pathogens including Emtamoeba hystolitica, Gardia lamblia, Trichomonas hominis, Hymenolepis nana, Escherichia coli, Shigella spp, Proteus mirabilis, and Klebsiella oxytoca. Cases of diarrhoea with negative pathogen search were 1,612 cases (62.19%). The diarrhoea peak was observed during the dry seasons, and the age group under 11 months was the most affected was (57.3%). CONCLUSION: This study describes the evidence of RVA infection among diarrhoeic children below five years of age in N'Djamena, thus indicates a serious health burden. Malnourishment younger age was the higher risk factor. Further studies are needed to determine the circulating strains prior to considering introduction of RVA vaccine and setup a routine rotavirus surveillance in Chad.

• #viral gastroenteritis research and epidemiology
• #hepatitis viruses studies and epidemiology
• #congenital anomalies and fetal surgery
• #medical microbiology

Low Prevalence and Risk Factors Related to HIV-1 Mother to Child Transmission under Option B+ Program at 3 Referral Military and Public Hospitals in Cameroon

Sabine Aimée Touangnou-Chamda, Maurice Boda, Arnaud Franck Elang, Donatien Serge Mbaga, Éric Simo, Sébastien Kenmoe et 9 autre(s)

Asian Journal of Research in Infectious Diseases

Immunodeficiency Virus type 1 (HIV-1) Mother-To-Child Transmission (MTCT) prevalence and its predictors. Following the limited success achieved with the previous MTCT prevention programs, the Cameroon’s public health ministry adopted in 2014 the Option B+ program that recommends a systematic lifelong treatment to all HIV positive pregnant woman.
 Study Design: A case-control study was conducted within two groups: a reference group constituted of exposed infants from HIV positive mothers undergoing Option B+ program, and a control group of infants from Anti-Retroviral Treatment (ART) naive HIV positive mothers during pregnancy.
 Place and Duration of Study: Douala and Yaounde Military Hospitals (HMR2 and HMR1 respectively) as well as the Bertoua Regional Hospital (HRB), From October 2017 to March 2018.
 Methodology: This research included infected mother - exposed child pairs. Infected mothers’ sociodemographic and clinical characteristics were reported. Infants sampled at six weeks at the HIV MTCT prevention units were tested at the Military Health Research Center for HIV-1 RNA early detection through rtPCR with Abbott m2000sp automated system. Multivariate logistic regression model was built to assess the predictors of MTCT and to compare groups.
 Results: Within the study period, the overall HIV-1 prevalence in the 107 six weeks old reference group infants and 23 control group infants was nil and 4.35% (1/23) respectively. Logistic regression showed that predictors of HIV-1 MTCT were: home delivery p=0.03 and absence of ART during pregnancy p = 0.04.
 Conclusion: Vertical transmission of HIV-1 infection is more likely in ART naïve pregnant women as compared to their counterparts established on ART. Hence, implementation of the Option B+ appear to be very essential in eliminating HIV-1 MTCT. Consequently, a systematic enrolment of these pregnant women living with HIV if scaled up, would be very instrumental in eliminating HIV-1 MTCT in Cameroon.

• #hiv/aids research and interventions
• #hiv, drug use, sexual risk
• #hiv/aids impact and responses
• #medicine

Epidemiology of Group A Rotavirus in children under five years of age with gastroenteritis in N’Djamena, Chad

Bertrand Djikoloum, Mahamat Fayiz Abakar, Valentine Ngum Ndze, Rahinatou Ghapoutsa Nkandi, Carine Ngah Enjeh, Pidou Kimala et 2 autre(s)

Research Square

Abstract Background : Group A Rotaviruses (RVA) is one of the most common causes of severe diarrhoea in infants and children under 5 years of age. Unlike other African countries where RVA surveillance is active, with routine circulating strains check, in Chad there is not currently RVA surveillance and vaccine introduced in the routine vaccination program. The objective of this study was to determine the prevalence and associated risk factors of RVA gastroenteritis in N'Djamena in view show the impact of RVA on the health of children under five years of age. Method : This study comprised two parts, (1) a cross-sectional study involving the detection of RVA VP6 protein by ELISA from stool samples collected in four hospitals in N'Djamena between August and November2019 from children aged five years and below, as well as a determination of risk factors through a questionnaire; and (2) a retrospective study consisting of analysing record of stool examinations to determine the frequency of diarrheic gastroenteritis among children aged five and below within the period from January 2016 to December 2018. Results : For the cross-sectional study, 141 samples were collected and analysed. The percentage of infected individuals was 12.76% (18/141) with males (61.11 %) being the more affected (sex ratio: 1.57). Children under 12 months were the most infected age group (44.44 %) and 44.4% are malnourished. The mean Vesikari score shows that 38.8% of children are at summer of severity and 41.1% have moderate condition. For the retrospective study, 2’592 cases of gastroenteritis hospitalization were analysed and 980 (37.8%) positive cases (all germs combined) of diarrhoea recorded from January 2016 to December 2018. The pic was obtained during the dry seasons, and the age group the most affected was 0 to 11 months with 57.3%. Conclusion : This study describes the evidence of RVA induced gastroenteritis among children below five years of age in N’Djamena, thus indicate a serious health burden. Malnourish and younger age children were found to be the most at risk of infection. Further studies are needed to determine the strains circulating for considering the introduction of RVA vaccine and establishing a routine surveillance of the disease in Chad.

• #viral gastroenteritis research and epidemiology
• #animal virus infections studies
• #hepatitis viruses studies and epidemiology
• #rotavirus

Detection of diarrhoea associated rotavirus and co-infection with diarrhoeagenic pathogens in the Littoral region of Cameroon using ELISA, RT-PCR and Luminex xTAG GPP assays

Rahinatou N. Ghapoutsa, Maurice Boda, Rashi Gautam, Valantine Ngum Ndze, Akongnwi E. Mugyia, François‐Xavier Etoa et 2 autre(s)

BMC Infectious Diseases

BACKGROUND: Despite the global roll-out of rotavirus vaccines (RotaTeq/Rotarix / ROTAVAC/Rotasiil), mortality and morbidity due to group A rotavirus (RVA) remains high in sub-Saharan Africa, causing 104,000 deaths and 600,000 hospitalizations yearly. In Cameroon, Rotarix™ was introduced in March 2014, but, routine laboratory diagnosis of rotavirus infection is not yet a common practice, and vaccine effectiveness studies to determine the impact of vaccine introduction have not been done. Thus, studies examining RVA prevalence post vaccine introduction are needed. The study aim was to determine RVA prevalence in severe diarrhoea cases in Littoral region, Cameroon and investigate the role of other diarrheagenic pathogens in RVA-positive cases. METHODS: We carried out a study among hospitalized children < 5 years of age, presenting with acute gastroenteritis in selected hospitals of the Littoral region of Cameroon, from May 2015 to April 2016. Diarrheic stool samples and socio-demographic data including immunization and breastfeeding status were collected from these participating children. Samples were screened by ELISA (ProSpecT™ Rotavirus) for detection of RVA antigen and by gel-based RT-PCR for detection of the VP6 gene. Co-infection was assessed by multiplexed molecular detection of diarrheal pathogens using the Luminex xTAG GPP assay. RESULTS: The ELISA assay detected RVA antigen in 54.6% (71/130) of specimens, with 45, positive by VP6 RT-PCR and 54, positive using Luminex xTAG GPP. Luminex GPP was able to detect all 45 VP6 RT-PCR positive samples. Co-infections were found in 63.0% (34/54) of Luminex positive RVA infections, with Shigella (35.3%; 12/34) and ETEC (29.4%; 10/34) detected frequently. Of the 71 ELISA positive RVA cases, 57.8% (41/71) were fully vaccinated, receiving two doses of Rotarix. CONCLUSION: This study provides insight on RVA prevalence in Cameroon, which could be useful for post-vaccine epidemiological studies, highlights higher than expected RVA prevalence in vaccinated children hospitalized for diarrhoea and provides the trend of RVA co-infection with other enteric pathogens. RVA genotyping is needed to determine circulating rotavirus genotypes in Cameroon, including those causing disease in vaccinated children.

• #viral gastroenteritis research and epidemiology
• #infant nutrition and health
• #listeria monocytogenes in food safety
• #rotavirus

Antibacterial, Antiulcerogenic and Antioxidant Activities of the Stem Bark Extracts of Entada africana

Eric Tchamgoue Ngalani, Maurice Boda, S.H. Voundi Olugu, André Perfusion Amang, S.P. Bouopda Tamo, Paul Vernyuy Tan et 1 autre(s)

Journal of Natural Products and Resources

In Cameroon, like elsewhere, medicinal plants are successfully used to treat gastro-intestinal diseases. <i>Entada africana</i> is a medicinal plant which different parts are used to treat stomach pain, diarrhea, dysentery and many other diseases. In order to show the efficiency of this plant in the treatment of gastrointestinal disorders, its antibacterial, antiulcerogenic and antioxidant activities were evaluated at Department of Microbiology (Laboratory of Microbiology) and Department of Animal Biology & Physiology (Animal Physiology Laboratory); Faculty of Science, University of Yaoundé I, between Febuary 2015 and July 2016. Crude extract of <i>E. africana</i> was obtained using methylene chloride/methanol mixture and fractions by successive exhaustion in hexane, methylene chloride and ethyl acetate. Phytochemical analysis of secondary metabolites was done using colorimetric tests. The antibacterial study consisted to determine Inhibition Diameters (ID) by agar diffusion as well as the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using the tube macro dilution method against <i>E. coli, S. typhi, P. aeruginosa, K. pneumonia, S. aureus</i> and <i>B. cereus</i>. The anti-ulcerogenic and antioxidant properties of the methylene chloride/methanol crude extract was evaluated using indomethacin-induced ulcer in rats and levels of reduced glutathione (GSH) and malondialdehyde (MDA) in the stomach homogenate were measured. The phytochemical study revealed the presence of phenolics compounds. The Methylene chloride/methanol, hexane, methylene chloride and ethyl acetate extracts were active on the tested microorganisms with the following results respectively for ID and MIC: 8.50 mm ± 0.50 ≤ DI ≤ 18.00 mm ± 1.00 and 1.56 mg/mL ≤ MIC ≤ 6.25 mg/mL. The anti-ulcerogenic test showed that the methylene chloride/methanol extract exhibited a cytoprotective effect with ulcer indices varying from 1.98 ± 0.24 to 1.36 ± 0.14 when the rats were pretreated at 200 and 400 mg/kg, respectively. Tissue levels of MDA reduced (23.04 %) while those of GSH increased (14.29%) following treatment with extract. The antibacterial, anti-ulcerogenic and antioxidant activities exerted by these plant extracts could be due to the presence of phenolic compounds. These properties would make this plant an

• #ethnobotanical and medicinal plants studies
• #phytochemistry and biological activities of ficus species
• #african botany and ecology studies
• #phytochemical

A Comparative Study on Performance of Diesel Engine using Jatropha Biodiesel as Fuel

Ashokkumar Vangire, Maurice Boda, Namdev K. Gavade

International Journal of Trend in Scientific Research and Development

• #biodiesel production and applications
• #advanced combustion engine technologies
• #biodiesel
• #jatropha

Bioethanol potential of raw and hydrothermally pretreated banana bulbs biomass in simultaneous saccharification and fermentation process with Saccharomyces cerevisiae

Florent Awedem Wobiwo, Tanmay Chaturvedi, Maurice Boda, Élie Fokou, Thomas Happi Emaga, Iwona Cybulska et 3 autre(s)

Biomass Conversion and Biorefinery

Residual banana bulbs (RBB) were characterized and assessed as a potential starch and cellulose-based feedstock for bioethanol production. To facilitate the enzymatic digestibility, hydrothermal pretreatment was performed on RBB prior to simultaneous saccharification and fermentation (SSF) with Saccharomyces cerevisiae . Composition of RBB was similar to traditional starch and cellulose-based feedstocks with high glucan (60 g/100 gDM) and relatively low lignin content (7 g/100 gDM). Both amylase and cellulase were needed to efficiently hydrolyze RBB. The highest ethanol yield (310 kg EtOH/ton_DM_RBB, 93% of theoretical production based on total available glucose) was obtained with non-pretreated RBB. SSF can be carried out at lower RBB concentrations. Hydrothermal pretreatment affected negatively the bioethanol potential due to the loss of fermentable carbohydrates. In a case study of an African leading producer of bananas and plantains (Cameroon), the energy derived from bioethanol was 80 GWh ethanol/year and corresponded to 1.6% of the annual transportation requirement. This study shows that RBB is a promising alternative feedstock for bioethanol production.

• #biofuel production and bioconversion
• #food composition and properties
• #banana cultivation and research
• #biofuel

Activity, acute and Sub-acute toxicity and safety assesment of the hydroalcholic root extract of Diplotaenia turcica

Uğur Özdek, Y. Baþbuðan, S. Yýldýrým, Maurice Boda, M. Fýrat, Y. Deðer

Indian Journal of Animal Research

Diplotaenia turcica is widely utilized in conventional treatment in the east of Turkey. Due to the insufficient data on the safety profile, the acute and sub acute toxicity of Diplotaenia turcica was determined. Furthermore, total phenolic content, flavonoid content and antioxidant activity of the extract were determined. The acute toxicity of hydroalcoholic root extract of Diplotaenia turcica (HREDT) was evaluated in mice after administration of single oral dose at the 5000 mg/kg (acute model) and rat after 28 days orally administration at the dose range of 250, 500 and 1000 mg/kg (subacute model). According to result, the LD50 value of HREDT was found to be greater than 5000 mg/kg. In sub acute toxicity study, no statistically significant differences were observed in the values of hematological and pathological parameters in comparison with control group. It was determined that the glucose, triglyceride, cholesterol and LDL levels exerted a significant effect depending on the HREDT doses. The results from the present study found out that HREDT did not produce any toxic effects or deaths in animals for both single and chronic administration. Additionally, HREDT showed moderate antioxidant activities and exhibited relatively notable total phenolic content.

• #essential oils and antimicrobial activity
• #phytochemicals and antioxidant activities
• #bee products chemical analysis
• #acute toxicity

Acidogenic fermentation of potato wastes to produce carboxylate platform chemicals : influence of cations used for pH control

Florent Awedem Wobiwo, Ebenezer Djiazet, Thomas Happi Emaga, Maurice Boda, Élie Fokou, Magali Deleu et 1 autre(s)

• #potato plant research
• #acidogenesis
• #fermentation
• #chemistry

Recovery of fibers and biomethane from banana peduncles biomass through anaerobic digestion

Florent Awedem Wobiwo, Virginie Korangi Alleluya, Thomas Happi Emaga, Maurice Boda, Élie Fokou, Sébastien Gillet et 2 autre(s)

Energy Sustainable Development/Energy for sustainable development

• #natural fiber reinforced composites
• #food composition and properties
• #anaerobic digestion
• #biogas

Acidogenic fermentation of starchy agroindustrial residues: metabolic profile & influence of thermal pretreatment

Florent Awedem Wobiwo, Thomas Happi Emaga, Maurice Boda, Élie Fokou, Magali Deleu, Patrick A. Gerin

• #food composition and properties
• #food industry and aquatic biology
• #microbial metabolites in food biotechnology
• #fermentation

Comparative biochemical methane potential of some varieties of residual banana biomass and renewable energy potential

Florent Awedem Wobiwo, Thomas Happi Emaga, Élie Fokou, Maurice Boda, Sébastien Gillet, Magali Deleu et 2 autre(s)

Biomass Conversion and Biorefinery

• #cassava research and cyanide
• #anaerobic digestion and biogas production
• #bioconversion
• #biogas

Biochemical methane potential of residues of three banana varieties from Cameroon : fresh and dry peduncles

Florent Awedem Wobiwo, Thomas Happi Emaga, Élie Fokou, Maurice Boda, Sébastien Gillet, Magali Deleu et 1 autre(s)

• #banana cultivation and research
• #methane
• #biology
• #horticulture

Biochemical Methane Potential of three varieties of fresh and dry banana peduncles from Cameroon

Florent Awedem Wobiwo, Thomas Happi Emaga, Élie Fokou, Maurice Boda, Magali Deleu, Patrick A. Gerin

• #nutritional studies and diet
• #nuts composition and effects
• #food composition and properties
• #biology

Anti-Helicobacter and gastroduodenal cytoprotective actions of the leaf aqueous extract of Ocimum suave (Lamiaceae)

Paul Vernyuy Tan, Christophe Mezui, Maurice Boda

Journal of Medicinal Plants Research

The gastroduodenal cytoprotective potential of the leaf aqueous extract of Ocimum suave(Lamiaceae) was investigated in rats using several ulcer-inducing methods. The anti-Helicobacter property of the extract was further assessed in vitro against Helicobacter pyloriCCUG-39500. The results obtained indicated that in all cases, orally administered extract (125 to 500 mg/kg) dose-dependently prevented lesion formation, with significant increases in gastric mucus production. The dose-500 mg/kg completely inhibited HCl/ethanol lesions but intraperitoneal indomethacin did not significantly reduce this effect. Honey-250 mg/kg, in combination with the extract-250 mg/kg, offered 50% prevention of ethanol-induced lesions, but O. suave alone (500 mg/kg) was more potent (62% inhibition) compared with honey alone (35% inhibition) at the same dose. In pylorus ligation, gastric acidity (91 mEq/L) was high compared with the controls (68 mEq/L), but 79% lesion inhibition was achieved. Mucus secretion (116 mg at 500 mg/kg) was most significant in highly acidic gastric environments compared with the controls (53 mg). The extract (12 mg) had anti-H. pylori effects (inhibition diameter, 33 mm; minimum inhibitory concentration (MIC), 1.17 mg/ml; minimum bactericidal concentration (MBC), 2.34 mg/mg). The cytoprotective actions of the extract are associated with its gastric mucosal re-enforcing effects. The extract possesses both anti-Helicobacterand gastro-duodenal cytoprotective effects, and may be useful in an antiulcer regimen without antimicrobial, antacids and antisecretory agents.   Key words: Helicobacter pylori, Ocimum suave, cytoprotection, gastroduodenal ulcer.

• #helicobacter pylori-related gastroenterology studies
• #phytochemistry and bioactive compounds
• #advances in cucurbitaceae research
• #chemistry

In vitro and in vivo anti- Helicobacter/Campylobacter activity of the aqueous extract of Enantia chlorantha

Paul Vernyuy Tan, Maurice Boda, François‐Xavier Etoa

Pharmaceutical Biology

The aqueous extract of Enantia chlorantha Oliver (Annonaceae) stem bark, a plant widely used in Cameroon for the traditional treatment of gastritis and stomach problems, was assessed for in vitro and in vivo anti-Helicobacter/Campylobacter properties using the well diffusion assay, agar dilution assay, and killing rate determination. The in vitro activity was dose-dependent, and the same antimicrobial parameters (MAQ = 0.63 mg; MIC = 0.39 mg/mL; MBC = 1.56 mg/mL; ET(100) = 8 h) were obtained for both H. pylori and C. jejuni/coli. When the plasma active principle concentration equivalence was determined in vitro using plasma from rats exposed to a single dose (3000 mg/kg) of the extract, the peak absorption of E. chlorantha active principle against H. pylori occurred at 2 h. Plasma activity was nil 8 h after extract administration. The in vivo H. pylori eradication potency of the extract was assessed using mice infected with H. pylori. Antral mucus sample cultures from mice treated with E. chlorantha extract (500 and 1000 mg/kg for 3 days) did not yield any growth. The results suggest that in addition to its in vitro activity, E. chlorantha water extract also possesses in vivo antibiotic effects against H. pylori.

• #helicobacter pylori-related gastroenterology studies
• #microbial metabolites in food biotechnology
• #phytochemistry and bioactive compounds
• #in vivo

ACUTE AND SUB-ACUTE TOXICITY PROFILE OF THE AQUEOUS STEM BARK EXTRACT OF ENANTIA CHLORANTHA OLIVER (ANNONACEAE) IN LABORATORY ANIMALS

Paul Vernyuy Tan, Maurice Boda, George Enow-Orock, François‐Xavier Etoa, Pauline Bitolog

Summary Enantia chlorantha Oliver (Annonaceae), widely used in Cameroonian folk medicine, has been previously shown to possess anti-ulcer, anti- trypanosomial and antiHelicobacter properties. Other investigations have revealed the anti-malarial, antiviral, antibacterial and anti-hepatotoxic properties of this plant. In the present study the acute and sub-acute toxicity profiles of the aqueous stem-bark extract was evaluated. Swiss mice were administered single oral doses of 1000, 3000 and 5000 mg/kg and monitored for death and growth impairment for seven days (acute toxicity). In sub-acute toxicity, experimental rats, received daily doses of 250, 500, and 1000 mg/kg for 42 consecutive days and the toxic effects of the extract were assessed using biochemical and haematological parameters as well as the study of histological sections of vital body organs ( heart, lungs, liver, kidneys, spleen, gonads and stomachs). No death or growth impairment was noticed in the mice in acute toxicity test. At 1000 mg/kg in the sub-acute toxicity study, the rats presented histopathological signs in the liver, lungs and kidneys, as well as significant (P< 0.05) increases in values of ALT, AST and platelet counts. The rest of the organs studied showed no signs of pathology. The extract of E. chlorantha, is not toxic in acute intake up to 5000 mg/kg, but can cause lung, hepatic and kidney disorders following medium-to-long term use at doses greater than 500 mg/kg.

• #traditional and medicinal uses of annonaceae
• #phytochemistry and biological activities of ficus species
• #phytochemistry and bioactive compounds
• #acute toxicity

Rapid in vivo screening method for the evaluation of new anti helicobacter medicinal preparations

Maurice Boda, Paul Vernyuy Tan, Barthélemy Nyasse

African Journal of Traditional Complementary and Alternative Medicines

The objective of this study was to devise a rapid mouse model for the in vivo screening of new anti Helicobacter pylori products. Six to eight week-old mice pre-treated (7 days) with Amoxicillin/Metronidazole (25 mg/kg) to eliminate all Helicobacter-like organisms were inoculated (4x per week) with 200 µl of a bacterial culture (108 CFU/ml of H. pylori CCUG-39500). Colonisation of mouse stomach was assessed from day 1 to 15 post inoculation by the Gram stain, rapid urease test and antral mucus culture. These findings were used as a mouse model of Helicobacter pylori infection to assess the in vivo anti Helicobacter activities of two plant-derived molecules with proven cytoprotective, ulcer healing and in vitro anti Helicobacter properties (TN, a tabersonine chloride alkaloid from the fruits of Voacanga Africana and PAL, a protoberberine alkaloid ((7,8-dihydro-8-hydroxy-palmatine) from the bark of Enantia chlorantha). For up to 6 days post inoculation, the test organisms were recoverable by culture from 87.5% of the antral mucus samples while 100% of Gram stains were positive. The infection tended to clear naturally from day 9. Fifteen days post infection, only Gram stains were still positive (37.5%). Three-day oral administration of TN, PAL (50 mg/kg) and Metronidazole (25 mg/kg) completely eliminated the bacterial strain from the gastric antral mucus compared with the controls. This 4-week model is proposed as a rapid screening tool for in vivo evaluation of new anti H. pylori products in order to select candidates for detailed investigations. African Journal of Traditional, Complementary and Alternative Medicines Vol. 3(4) 2006: 102-114

• #helicobacter pylori-related gastroenterology studies
• #gastroesophageal reflux and treatments
• #gastrointestinal motility and disorders
• #in vivo