Aqueous extracts of Syzygium brazzavillense can inhibit the infection with coxsackievirus B4 in vitro.

Traditional practitioners commonly use plant crude extracts to treat various diseases in patients with symptoms that can be seen during enterovirus infections. In this study, the antienteroviral activity of medicinal plants from the Republic of Congo has been evaluated in vitro. Through an ethnopharmacological approach, seven plants grouped into six families were identified. Aqueous and organic extracts of various organs from these plants were prepared. The organic extracts at subcytotoxic concentrations did not inhibit the cytopathic effect (CPE) induced by coxsackievirus (CV)B1-5, CVA6, poliovirus type 1, and enterovirus 71. The aqueous extract of Syzygium brazzavillense, but not those of other plants, inhibited the CPE induced by CVB3 and CVB4 at 30 µg/mL (CC50 ; 2800 µg/mL, IC50 ; 0.8 µg/mL) and by CVB2 and poliovirus type 1 at higher concentrations. When aqueous extract of this plant was mixed with CVB4, the replication of the virus was inhibited. In conclusion, aqueous extracts of Syzygium brazzavillense can inhibit the infection with CVB4 and other enteroviruses in vitro. The present ethnopharmacological investigation helped to identify a plant with potential properties useful to combat enterovirus infections.

Molecular Detection of Helicobacter pylori and its Antimicrobial Resistance in Brazzaville, Congo.

BACK GROUND: Helicobacter pylori infection is involved in several gastroduodenal diseases which can be cured by antimicrobial treatment. The aim of this study was to determine the prevalence of H. pylori infection and its bacterial resistance to clarithromycin, fluoroquinolones, and tetracycline in Brazzaville, Congo, by using molecular methods. MATERIAL AND METHODS: A cross- sectional study was carried out between September 2013 and April 2014. Biopsy specimens were obtained from patients scheduled for an upper gastrointestinal endoscopy and were sent to the French National Reference Center for Campylobacters and Helicobacters where they were tested by molecular methods for detection of H. pylori and clarithromycin resistance by real-time PCR using a fluorescence resonance energy transfer-melting curve analysis (FRET-MCA) protocol, for detection of tetracycline resistance by real-time PCR on 16S rRNA genes (rrnA and rrnB), for detection of point mutations in the quinolone resistance-determining regions (QRDR) of H. pylori gyrA gene, associated with resistance to quinolones, by PCR and sequencing. RESULTS: This study showed a high H. pylori prevalence (89%), low rates of clarithromycin and tetracycline resistance (1.7% and 2.5%, respectively), and a high rate of quinolone resistance (50%). CONCLUSION: Therefore, the use of standard clarithromycin-based triple therapy is still possible as an empiric first-line treatment as well as prescription of bismuth-based quadruple therapy, which includes tetracycline, but not a levofloxacin-based triple therapy because of the high rate of resistance to fluoroquinolones.

Genetic evidence of regulatory gene variants of the STAT6, IL10R and FOXP3 locus as a susceptibility factor in uncomplicated malaria and parasitaemia in Congolese children.

BACKGROUND: Regulatory T cells (Tregs) are a subset of T cells that play an important role in modulating T effector responses during infectious challenges. The aim of this study was to evaluate possible associations between regulatory gene polymorphisms and the risk of uncomplicated malaria and the control of Plasmodium falciparum parasite density levels. METHODS: Twelve regulatory single nucleotide polymorphisms (SNPs) in the promoter regions of FOXP3 (ss270137548, rs11091253), IL10RA (rs56356146, rs7925112), IL10RB (rs8178433, rs8178435, rs999788), STAT6 (rs3024941, rs3024943, rs3024944) and TNFRSF18 (ss2080581728, rs3753344) were genotyped in a cohort of Congolese children. Studied subjects were followed up (passively) during one year. The children who experienced one or several clinical episodes were genotyped as "uncomplicated malaria" group (n=179) and those children who did not experience any episode were genotyped as "asymptomatic children" group (n=138). RESULTS: The prevalence of rs3024944CC genotype of STAT6 was significantly higher in the group of asymptomatic children compared to that of uncomplicated malaria (P=0.003). Similarly, the minor allele rs3024944C was more prevalent in the group of asymptomatic children (P=0.019). Two novel SNPs were observed including -163T/G (ss491228441) in IL10RA gene and -163C/T (ss491228440) in TNFRSF18 gene. The genotype ss491228441TT and the minor allele ss491228441G of the IL10RA were more frequent in the group of asymptomatic children (P=0.006 and P=0.007, respectively). The genotype rs11091253CT of the FOXP3 was associated with high parasite density levels. In addition, a new promoter IL10RA variant (ss491228441) contributes to shield against mild malaria. CONCLUSION: The study indicated that the STAT6 promoter polymorphism rs3024944 was associated with uncomplicated malaria, whereas the FOXP3 promoter variant rs11091253 was associated with significant P. falciparum parasitaemia levels. These genetic data may contribute to the understanding of molecular mechanisms that regulate immune response to P. falciparum infections.

Pentaclethra eetveldeana Leaves from Four Congo-Brazzaville Regions: Antioxidant Capacity, Anti-Inflammatory Activity and Proportional Accumulation of Phytochemicals.

Oxidative stress and inflammation play a key role in the occurrence of neurodegenerative diseases. Traditionally, Pentaclethra eetveldeana leaves are used in dementia treatment. Therefore, this study aimed to evaluate the antioxidant and anti-inflammatory activities as well as the phytochemical composition of Pentaclethra eetveldeana leaves from four Congo-Brazzaville regions. The 1.2-diphenyl-1-picrylhydrazyl radical-scavenging, ß-carotene bleaching and molybdenum reduction assays were used to assess the antioxidant activity. The protein denaturation and erythrocyte membrane stabilization tests were used to analyze the anti-inflammatory activity. Phytochemical screening, the quantification of polyphenols by spectrophotometry, as well as the determination of extraction yields were carried out. It was found that the extracts reduced molybdenum; furthermore, compared to ascorbic acid, they showed better antiradical activity and inhibited lipid peroxidation. Moreover, globally, the membrane-stabilizing power of the aqueous extracts was superior or comparable to diclofenac, while the same extracts were less effective for the inhibition of denaturation. All of the aqueous extracts contained polyphenols, saponins, alkaloids, anthraquinones, reducing sugar and cardiotonic glycosides. The total polyphenols, tannins and proanthocyanidins are produced proportionally from one region to another. Finally, the leaves from Brazzaville and Boundji contain flavonols, while those from Makoua and Owando contain flavones. Thus, Pentaclethra eetveldeana leaves contribute to traditional dementia treatment through their antioxidant and anti-inflammatory properties.

Inflammatory biomarkers and prediction of insulin resistance in Congolese adults.

Several studies have shown that low levels of adiponectin (ADP) and high levels of alpha tumor necrosis factor (NFT) increase the risk or severity of many cardiometabolic diseases associated with insulin resistance. The main objective of this study was to evaluate the association between plasma adipokines and IR measured by HOMA-IR. The secondary objective was to determine the biomarker of the potential inflammation to predict IR in Congolese melanoderm subjects residing in Brazzaville. This cross-sectional study was conducted on 234 apparently healthy participants over the age of 18. Socio-demographic and clinical data were collected. Biological data, including the total ADP and NFT dosage, were measured using the ELISA method. Participants were categorized into two groups according to HOMA-IR ≥ 2.5. Univariate and multivariate logistic regression analyses were conducted to identify risk factors for insulin resistance. An optimized model was obtained after the logistic regression. The analysis of the receptor's operating characteristics (OCR) was performed to determine the optimal threshold value and diagnostic characteristics, as well as the area under the curve (ASC). ADP averages were significantly low (11.49 ± 7.61 ng/mL; P < 0.001) while those of TNF were significantly higher (96.03 ± 44.09 pg/mL) in the HOMA-IR group ≥ 2.5. There was a positive and significant correlation (p < 0.05) between BMI, TT, CRPhs, TNF and HOMA-IR. And a negative and significant correlation was noted between ADP and HOMA-IR (r = - 0.39; P < 0.01). Similarly, a negative and significant correlation (p < 0.01) was noted between BMI, TT, TNF, CRPhs and ADP. The optimal threshold value of the total ADP for predicting IR was 17.52 ng/mL with a sensitivity of 89% [IC 95% (0.83-0.95)], 56% specificity [IC 95% (0.47-0.65)] and a CSA of 0.76 [IC 95% (0.69-0.81)]. After logistic regression, the CSA of the optimized model was 0.84 [IC 95% (0.79-0.89)]. ADP can be used as a highly plausible IR prediction biomarker.

Occurrence of human astrovirus associated with gastroenteritis among Congolese children in Brazzaville, Republic of Congo.

INTRODUCTION: Acute viral gastroenteritis is a major public health concern, especially among children younger than 5 years of age. The aim of this study was to determine the occurrence of human astrovirus infection in children with acute gastroenteritis. METHODS: Stool specimens were collected from 506 children under 5 years of age hospitalized with acute diarrhoea (289 male and 208 female), and human astrovirus was investigated by RT-PCR. Associations of socio-demographic, clinical, and behavioural conditions with infection were analysed. RESULTS: The overall prevalence of human astrovirus was found to be 10.3%. The mean age of positive cases was 12.41 ± 6.21 months and this was associated with infection (p = 0.013). Children >18 months of age were at three times the risk of infection when compared to those aged 0-6 months (odds ratio (OR) 3.19, 95% confidence interval (CI) 1.15-8.88; p = 0.026). Children living in houses with more than one room (OR 0.60, 95% CI 0.28-0.96; p = 0.036) and mothers using treated water (OR 0.47, 95% CI 0.25-0.86; p = 0.015) were associated with reduced infection. CONCLUSIONS: In this study, infection with astrovirus was common in acute gastroenteritis cases among children younger than 5 years of age. Drinking treated water and living in non-crowded environments protected the children from infection.

In vitro evaluation of antiplasmodial activity of extracts of Acanthospermum hispidum DC (Asteraceae) and Ficus thonningii Blume (Moraceae), two plants used in traditional medicine in the Republic of Congo.

The aim of this study was to evaluate extracts from two medicinal plants, Acanthospermum hispidum and Ficus thonningii, used in traditional medicine in Congo Brazzaville, for in vitro antiplasmodial activities against two laboratory strains of Plasmodium falciparum: the chloroquine sensitive 3D7 and the chloroquine resistant Dd2. ELISA HRP2 assay was used to evaluate the in vitro inhibitory activity of the extracts alone or in combination with chloroquine. Cytotoxicity was assessed on human HeLa cell line and reflected by the selectivity index. Methanolic extract of Acanthospermum hispidum exhibited a strong and a moderate inhibitory activity on the growth of Dd2 and 3D7 at 2.8 µg/ml and 9.2 µg/ml concentrations respectively with a selectivity index >10. The combination of the most active extract (methanolic extract of Acanthospermum hispidum) with chloroquine showed a synergistic interaction on both strains. The good selectivity index of Acanthospermum hispidum on HeLa cells reflects the safety of this plant. Extracts from Ficus thonningii did not show any promising antiplasmodial activity on both 3D7 and Dd2. Except the methanolic extract which exhibited a slight antiplasmodial activity with inhibitory concentration and selectivity index corresponding to 9.61 µg/ml and 11.16 respectively. Methanolic extract of Acanthospermum hispidum exhibited moderate to high inhibitory activity on 3D7 and Dd2 laboratory strains and a synergistic antimalarial effect when combined with chloroquine. Ficus thonningii seems to have no antimalarial activity. Phytochemical analysis, in vivo investigations using animal models and later clinical trials in collaboration with traditional practitioners are necessary to clarify the potential antimalarial activity of both plants.