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Introduction: Aucoumea klaineana, Canarium schweinfurthii, Cymbopogon nardus, Dacryodes edulis, and Eucalyptus citriodora are of Gabonese origin, believed to have insecticidal activity. This study contributes to vector control by the insecticidal activities (larvicidal and ovicidal) of five essential oils from these plants against Anopheles gambiae, a major vector of malaria in Gabon. Methods: The essential oils were extracted by hydrodistillation. Larvicidal and ovicidal effects of essential oils were performed using different concentrations on third and fourth instar larvae and eggs of A. gambiae vectors. The effects of these oils were examined on the mortality rate of larvae and eggs. Results: The essential oils of A. klaineana, C. schweinfurthii, C. nardus, A. edulis, and E. citriodora showed greater activity against mosquito larvae (7.33 < LC50 < 107.14) compared to eggs (22.80 < LC50 < 64.63). D. edulis showed the highest activity against Anopheles gambiae eggs and larvae. Of all plants, essential oils from A. klaineana showed the lowest activity of A. gambiae eggs and larvae. Larvae were more sensitive than eggs. All essential oils were toxic to the various aquatic vectors of malaria. Conclusion: The study reveals the potential ovicidal efficacy and larvicidal activity of these plants against A. gambiae.

The purpose of this work was to develop ethnopharmacological and biological studies of plants used in traditional medicine for the treatment of diarrheal diseases. This study results in scientific data that validates the uses of these plants in traditional medicine. Firstly, ethnopharmacological surveys were conducted with a few traditional healers from the provinces of Estuaire, Haut Ogooué and Woleu-Ntem in Gabon. Next, ethnobotanical data such as percentage of families, species, routes of administration, methods of preparation, parts used and number of plant names were analyzed and summarized. Finally, the antibacterial activities of some plants have been evaluated by diffusion and microdilution methods. Thirty-four (34) traditional healers were interviewed. A total of 90 plant species were identified during this study. They belong to 44 families, the most represented were Leguminoseae (13.33%), Apocynaceae (7.78%), Annonaceae (5.55%), Euphorbiaceae (4.44%) and Anacardiaceae (4.44%). Trees were used more (44.44%) than shrubs (32.22%), herbaceous plants (16.67%) and lianas (6.67%). The drug administration was mainly oral (84.62%) and by the anal route. Decoction and maceration were the two most used methods of preparation. Among identified plants, twenty-seven (27) plant extracts were subjected to microbiological analyzes. Plant extracts tested were active on Gram-negative and Gram-positive bacteria. Cola nitida extracts gave the best antibacterial activity against Enterococcus faecalis 103907 CIP. This study identified 90 antidiarrheal plant species and clearly shows the antimicrobial potential of several medicinal species.

BackgroundGabonese flora abounds in a significant reserve of plants in medical matter. Thus, medicinal plants occupy a significant place in African pharmacopeia. Aim of this work was to evaluate the antimicrobial, antioxidant, anti-inflammatory and cytotoxic properties of extracts ofGuibourtia tessmanii(Harms) J. Léonard.MethodsThe test for sensitivity to microorganisms was performed by the diffusion method, while the MICs and MBCs were evaluated by the microdilution technique. Antioxidant tests were performed by scavenging the DPPH and ABTS radicals. Anti-inflammatory activity was determined by protein denaturing and membrane stabilization methods. The cytotoxicity was evaluated on the tadpoles of the green frog.ResultsThe antibacterial activity shows that the Gt F2 fraction and the water-acetone extract produced the greatest inhibitions. The water, water-ethanol and water-acetone extracts exhibited bactericidal effects on the majority of bacteria. In the case of trapping of the DPPH radical, the IC50values varied from 6.92 ± 0.48 to 16.64 ± 0.20 μg/mL. For the decolouration of ABTS, oxidation was mainly inhibited by the water-acetetone, water-ethanol extracts and some fractions. The water and water-acetone extracts showed good inhibition of denaturation. The hemolysis test confirmed the good activities of the extracts. The lethal test showed that the LC50drops from 171.37 ± 9.25 to 58.25 ± 7.21 μg/mL after 24 and 96 h of exposure. In tadpoles exposed to 7.81 μg / mL of extracts, the first mortalities (12.5%) were observed on the second day of exposure. From the ninth day, the mortality rate increased (25%) until the 16th day.ConclusionOur results show thatGuibourtia tessmaniimay be a promising product for the isolations of molecules responsible for biological activities.

Two plants used in traditional medicine from Gabon were studied. The aim of this study was to study the biological properties and phytochemical analysis of Cylicodiscus gabunensis Harms and Morinda lucida Benth. These extracts were subjected to antimicrobial (diffusion, dilution), antioxidant (DPPH, ABTS) and inhibition of protein denaturation. The water-ethanol, water-acetone extracts and the partitioned extracts (F1 and F2) of Cylicodiscus gabunensis showed the greatest antibacterial activity on the majority of microbial strains and a good inhibition of denaturation with IC50 of 58.75 ± 2.10; 19.16 ± 2.00; 69.50 ± 2.00 and 17.49 ± 1.20 μg / mL respectively, compared to standards. Similarly, these extracts of Cylicodiscus gabunensis have anti-free radical capacities close to standards including vitamin C and butylated hydroxyanisole. The phytochemicals present in the extracts of Cylicodiscus gabunensis and Morinda lucida may be responsible for the biological activities studied.

Data on the prevalence of antibiotic resistance in Enterobacteriaceae in African wildlife are still relatively limited. The aim of this study was to estimate the prevalence of phenotypic intrinsic and acquired antimicrobial resistance of enterobacteria from several species of terrestrial wild mammals in national parks of Gabon. Colony culture and isolation were done using MacConkey agar. Isolates were identified using the VITEK 2 and MALDI-TOF methods. Antibiotic susceptibility was analysed and interpreted according to the European Committee on Antimicrobial Susceptibility Testing guidelines. The preliminary test for ESBL-producing Enterobacteriaceae was performed by replicating enterobacterial colonies on MacConkey agar supplemented with 2 mg/L cefotaxime (MCA+CTX). Extended-spectrum beta-lactamase (ESBL) production was confirmed with the double-disc synergy test (DDST). The inhibition zone diameters were read with SirScan. Among the 130 bacterial colonies isolated from 125 fecal samples, 90 enterobacterial isolates were identified. Escherichia coli (61%) was the most prevalent, followed by Enterobacter cloacae (8%), Proteus mirabilis (8%), Klebsiella variicola (7%), Klebsiella aerogenes (7%), Klebsiella oxytoca (4%), Citrobacter freundii (3%), Klebsiella pneumoniae (1%) and Serratia marcescens (1%). Acquired resistance was carried by E. coli (11% of all E. coli isolates) and E. cloacae (3% of all E. cloacae) isolates, while intrinsic resistance was detected in all the other resistant isolates (n = 31); K. variicola, K. oxytoca, K. pneumoniae, E. cloacae, K. aerogenes, S. marcescens and P. mirabilis). Our data show that most strains isolated in protected areas in Gabon are wild type isolates and carry intrinsic resistance rather than acquired resistance.

In Gabon, terrestrial mammals of protected areas have been identified as a possible source of antibiotic-resistant bacteria. Some studies on antibiotic resistance in bats have already been carried out. The main goal of our study was to detect extended-spectrum beta-lactamases (ESBLs) that are produced by enterobacteria from bats in the Makokou region in Gabon. Sixty-eight fecal samples were obtained from 68 bats caught in the forests located 1 km from the little town of Makokou. After culture and isolation, 66 Gram-negative bacterial colonies were obtained. The double-disk diffusion test confirmed the presence of ESBLs in six (20.69%) Escherichia coli isolates, four (13.79%) Klebsiella pneumoniae isolates, and one (3.45%) Enterobacter cloacae isolate. The analysis based on the nucleotide sequences of the ESBL resistance genes showed that all cefotaximase-Munichs (CTX-Ms) were CTX-M-15 and that all sulfhydryl variables (SHVs) were SHV-11: 41.67% CTX-M-15-producing E. coli, 16.67% CTX-M-15+SHV-11-producing E. coli, 8.33% CTX-M-15-producing K. pneumoniae, 25% CTX-M-15+SHV-11-producing K. pneumoniae, and 8.33% CTX-M-15-produced E. cloacae. This study shows for the first time the presence of multiresistant ESBL-producing enterobacteria in fruit bats in Makokou.

Antibiotic resistance occurs in the environment by multiplication and the spread of multidrug-resistant bacteria that would be due to an improper and incorrect use of antibiotics in human and veterinary medicine. The aim of this study was to establish the prevalence of E.coli producing Extended-Spectrum beta-Lactamase (ESBL) antibiotics from rats and gregarious animals in a semirural area of Gabon and to evaluate the origin of a resistance distribution in the environment from animal feces. The bacterial culture was carried out, and the identification of E. coli strains on a specific medium and the antibiotic susceptibility tests allowed establishing the prevalence. Characterization of resistance genes was performed by gene amplification after DNA extraction. On 161 feces collected in rats, 32 strains were isolated, and 11 strains of E. coli produced ESBL with a prevalence of 34.37%. Molecular tests showed that CTX-M genes 214 bp were identified in rats. The presence of CTX-M genes could have a human origin. So, the rats can carry ESBL-producing Enterobacteriaceae which poses a risk to human health and pets in this region of Gabon.

The goal of this work is to evaluate the antioxidant anti-inflammatory properties, the phenolic compounds content, and antimicrobial potential of water–acetone, water–ethanol, and water extracts of Pachylobus balsamifera. The phenolic compounds content was evaluated to estimate their effect on the antioxidant, anti-inflammatory, and antimicrobial potential of the plant. Antioxidant activities were examined by DPPH (2,2-diphenyl-1- picrylhydrazyl) and ABTS (2,2′-azino-bis) assays. Antiinflammatory activity was determined by the proteins denaturation inhibition method. All plant extracts were evaluated against six reference strains, eleven clinical isolates, and two fungal strains. Phenols content was highest in the water–acetone and water–ethanol extracts. The water extract showed strong anti-inflammatory effect. The water–acetone extract presented a strong antioxidant property and the highest antimicrobial activities against Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella Sp., and Neisseria meningitidis. The tested microorganisms showed sensitivity to all extracts of the plant with the exception of Escherichia coli 105182 CIP, Listeria innocua LMG 135668 BHI, Salmonella enterica, Salmonella typhi, and Neisseria gonorrhea. Our results suggest that Pachylobus balsamifera extracts contain antioxidant, anti-inflammatory, and antimicrobial properties.

Following the publication of this article [1], the authors noticed that Figs. 1, 2 and 3 were in the incorrect order and thus had incorrect captions. The images that were incorrectly published as Figs. 1, 2 and 3 should have been published as Figs. 2, 3 and 1 respectively.

Objective: To evaluate the phytochemical constituents, antioxidant and antimicrobial potential of water-acetone, water-ethanol and water extracts of Coula edulis (C. edulis), Pseudospondia longifolia (P. longifolia) and Carapa klaineana (C. klaineana). Methods: Presence of total phenols, flavonoids, tannins and proanthocyanidins was evaluated to estimate the effects of plants on microbial diseases. Water-acetone, water-ethanol and water extracts were examined for antioxidant activities. All plant extracts were evaluated against six reference strains, eleven clinical isolates and two fungal strains. Results: The contents of total phenols [(12 857.56 ± 1.00) mg gallic acid equivalent/100 g], flavonoids [(1 634.13 ± 1.88) mg quercetin equivalent/100 g], tannins [(2 672.00 ± 1.59) mg tannic acid equivalent/100 g] and proanthocyanidins [(395.11 ± 0.83) mg apple procyanidin equivalent/100 g] were highest in the water-acetone and water-ethanol extracts from C. edulis in comparison with P. longifolia and C. klaineana. The water-acetone, water-ethanol and water extracts from C. edulis presented the highest antimicrobial activities against Neisseria gonorrhoeae, Enterococcus faecalis CIP 103907, Pseudomonas aeruginosa and Salmonella sp. The tested microorganisms showed sensitivity to all extracts of P. longifolia and C. klaineana with the exception of Shigella dysenteriae CIP 5451, Pseudomonas aeruginosa and Salmonella typhi. Conclusions: Our results suggest that C. edulis extracts contain greater antioxidant and antimicrobial properties than P. longifolia and C. klaineana extracts.

Gout is caused by a chronic hyperuricemia whose complications are not currently well evaluated in Africa. The aim of this study was to determine the prevalence and risk factors of hyperuricemia and gout in 85 patients recruited. A total of 26 cases of hyperuricemia, i.e., 30.6% of the study population, with 12 cases of gout and seven cases of gouty access. In this population, hyperuricemia was proportional to age (p-value < 10−4, OR = 2.6), but it was more prevalent in men, 23.5% versus 7.1% for women (p-value = 0.0047). In addition, none of these women showed signs of a gouty affection. Consumption of alcohol (OR = 13) and nucleoprotein-rich foods, obesity (BMI 30 kg/m2; OR = 6), family history of gout (OR = 6.8), as well as diseases such as high blood pressure (associated with taking diuretics; OR = 1.7), renal insufficiency (OR = 4.4) and diabetes (p < 0.049) were the main factors of the diseases associated with gout and hyperuricemia in this population. The biochemical role of these factors may increase and/or decrease the processes of synthesis and/or elimination of uric acid by acting on metabolites involved in the regulation of urate production.

Introduction Despite advances in medical technology, the fight against cancer remains difficult in developing countries. Thus, traditional medicine remains the first choice or sometimes still, the only opportunity for treatment. The purpose of this work was to popularize the medicinal plants used by Gabonese herbal therapists in the treatment of cancers by an ethnopharmacological survey. Methods In four localities of the Woleu-Ntem province, traditional healers were interviewed using a semi-structured questionnaire. Collected data were analyzed by descriptive statistical methods and various quantitative indices. The anticancer potential and toxicity of medicinal plants were confirmed by the bibliographic review. Results Traditional healers of Woleu-Ntem use 51 species of medicinal plants in cancers management and related diseases. These species are grouped into 49 genera and 29 families, the best-represented being Euphorbiaceae, Annonaceae, Apocynaceae, Myristicaceae and Rubiaceae. Barks are mainly used, followed by leaves. Decoction and maceration were the main methods of preparation. The oral absorption was the main route of administration. Colorectal, breast, cervical and liver cancer were the most cancers treated. The results of the literature search show that most of the plants in the survey have anticancer properties and are non-toxic at dosage and oral use by traditional healers. Conclusions The present work is the first study reporting information on the different Gabonese medicinal plants used against cancer. About 16 plant species have been mentioned for the first time as anticancer agents. These species could constitute a scientific database for the research of new bioactive molecules against cancers and other diseases.

Background: Plasmodium falciparum causes severe clinical manifestations by sequestering parasitized red blood cells (PRBC) in the microvasculature of major organs such as the brain. This sequestration results from PRBC adherence to vascular endothelial cells via erythrocyte membrane protein 1, a variant parasite surface antigen. Objective: To determine whether P. falciparum multiple genotype infection (MGI) is associated with stronger PRBC cytoadherence and greater clinical severity. Methods: Nested polymerase chain reaction was used to genotype P. falciparum isolates from symptomatic children and to distinguish between single genotype infection (SGI) and MGI. PRBC cytoadhesion was studied with cultured human lung endothelial cells. Results: Analysis of two highly polymorphic regions of the merozoite surface antigen (MSP)-1 and MSP-2 genes and a dimorphic region of the erythrocyte binding antigen-175 gene showed that 21.4% and 78.6% of the 42 children had SGI and MGI, respectively. It also showed that 37 (89%) of the 42 PRBC samples expressed MSP-1 allelic family K1. Cytoadherence values ranged from 58 to 1811 PRBC/mm2 of human lung endothelial cells monolayer in SGI and from 5 to 5744 PRBC/mm2 in MGI. MGI was not associated with higher cytoadherence values or with more severe malaria. Conclusions: These results suggested that infection of the same individual by multiple clones of P. falciparum does not significantly influence PRBC cytoadherence or disease severity and confirmed the predominance of the MSP-1 K1 genotype in southeastern Gabon.

Aim of this work was to evaluate the phytochemical constituents, antioxidant and antimicrobial potential of water-acetone, water-ethanol and water extracts of Englerina gabonensis and Sterculia tragacantha.Presence of phenols was evaluated to estimate the effects of plants on microbial diseases. Water-acetone, water-ethanol and water extracts were examined for antioxidant activities. All plant extracts were tested against six reference strains, eleven clinical isolates and two fungal strains.Phenolic content were highest in the water-acetone and water-ethanol extracts from Englerinagabonensis in comparison with Sterculia tragacantha.The AAI (Antioxidant Activity Index)of water-acetone and water-ethanol extracts of Englerina gabunensis are superiors with 2. Plant extracts of Sterculia tragacantha show weak antioxidant activity (AAI < 0.5).The aqueous extract of Englerina gabonensis has a bactericidal effect on Salmonella Spp. Water-ethanol extract is bactericidal on Bacillus cereus LMG 13569 BHI, Salmonella Sppand Neisseria meningitides. Water-acetone extract presents a bactericidal activity on Enterococcus faecalis103907 CIP, Escherichi coli, Staphylococcus aureus, Acinetobacter baumanniiand Neisseria meningitides.Our results suggest that Englerina gabonensis extracts contain greater antioxidant and antimicrobial properties than Sterculia tragacantha extracts.

International audience; BACKGROUND: The epidemiological and molecular characteristics of hepatitis C virus (HCV) infection in the general population have been poorly investigated in Africa. The aim of this study was to determine the prevalence, genotype distribution and epidemic history of HCV in the Gabonese general population. METHODS/PRINCIPAL FINDINGS: A total of 4042 sera collected from adults in 220 villages in all nine administrative areas of the country were screened for antibodies to HCV. HCV NS5B region sequencing was performed for molecular characterization and population genetic analyses. Of 4042 tested sera, 455 (11.2%) were positive. The seroprevalence of HCV varied significantly by administrative area, with the highest rate in Ogooué-Lolo province (20.4%) and the lowest in Ogooué-Maritine province (3.7%). History of parenteral injections, past hospital admission and age over 55 years were independent risk factors for HCV infection (p

International audience; BACKGROUND: Intrafamilial and sexual transmission of hepatitis C virus (HCV) are still being debated, and little is known about such transmission in central Africa. OBJECTIVE: To examine the rate of intrafamilial transmission of HCV between patients and their household members. STUDY DESIGN: A cross-sectional study was conducted in Dienga, a remote village in Gabon, involving 195 household members of 14 index cases of HCV infection. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for antibody to HCV by an enzyme immunoassay (Monolisa anti-HCV plus version 2). Positive samples were tested for HCV RNA and genotyped by amplification and phylogenetic analysis of a fragment of the NS5B gene. RESULTS: HCV antibody was found in 13/195 (6.7%) household contacts, comprising 5/14 (35.7%) sexual partners and 8/114 (7%) relatives. None of the children of index patients tested positive. HCV RNA was detected in only five household members with HCV antibody. The same genotypes were found in only two of five couples, both couples being sexual partners. Parenteral risk factors were not more likely to be reported by people positive for HCV antibody than by those who were negative. Age over 50 years was the only independent predictor of positivity for HCV antibody. CONCLUSIONS: This study indicates, as previously suggested, that the spread of HCV in central Africa is due to a cohort effect, with previous, possibly iatrogenic, transmission rather than intrafamilial or sexual transmission.

Hepatitis C (HCV) molecular epidemiology is documented poorly in central African countries. In response to this, a population-based study of 319 consenting adults resident in a remote village of Gabon was undertaken (mean age: 38 years; age range: 13–85+; sex ratio: 0.74). Screening for anti-HCV antibodies was performed using ELISA and recombinant immunoblot assay. Seropositive samples were assessed further with viral load and genotyping techniques. Sixty-six (20.7%) individuals were HCV seropositive. Viral loads ranged from 600 to 24.9 million IU/ml (median: 372,500). Seroprevalence and viral loads increased significantly with age (P

Background Hepatitis C virus (HCV) infection is a major global public health problem in both developed and developing countries. The prevalence and genetic diversity of HCV in pregnant women in Gabon, central Africa, is not known. We therefore evaluated the prevalence and the circulating genotypes of HCV in a large population cohort of pregnant women. Methods Blood samples (947) were collected from pregnant women in the five main cities of the country. The prevalence was evaluated by two ELISA tests, and the circulating genotypes were characterized by sequencing and phylogenetic analysis. Results Twenty pregnant women (2.1%) were infected with HCV. The seroprevalence differed significantly by region (p = 0.004) and increased significantly with age (p = 0.05), being 1.3% at 14–20 years, 1.1% at 21–25 years, 1.9% at 26–30 years, 4.1% at 31–35 years and 6.0% at > 35 years. Sequencing in the 5'-UTR and NS5B regions showed that the circulating strains belonged to genotypes 4 (4e and 4c). Conclusion We found that the HCV seroprevalence in pregnant women in Gabon is almost as high as that in other African countries and increases with age. Furthermore, only genotype 4 (4e and 4c) was found. More extensive studies aiming to evaluate the prevalence and heterogeneity of HCV genotypes circulating in the general population of the country are needed.