Phenylpropanoid-conjugated iridoid glucosides from leaves of Morinda morindoides.

Three phenylpropanoid-conjugated iridoid glucosides, acetylgaertneric acid (1), acetyldehydrogaertneroside (2), and dehydrogaertneric acid (10), together with nine known related iridoid glucosides (3-9, 11, and 12), two coumaroyl alkaloids, one benzenoid, and three flavonoid glucosides were isolated from leaves of Morinda morindoides (Rubiaceae). Structures of these isolated compounds were determined using spectroscopic analysis. Compounds 1-18 and previously isolated compounds (19-29) were evaluated for anti-trypanosomal activity against Trypanosoma cruzi Tulahuen strain (trypomastigote and amastigote) together with cytotoxicity against host cells, new-born mouse heart cells. Among them, molucidin (21) and prismatomerin (22) exhibited good anti-trypanosomal activity (IC50 of 4.67 and 5.70 µM, respectively), together with cytotoxicity (CC50 of 2.76 and 3.22 µM, respectively). Compounds 1-18 did not show anti-malarial activity against a chloroquine/mefloquine-sensitive strain of Plasmodium falciparum.

Phenylpropanoid conjugated iridoids with anti-malarial activity from the leaves of Morinda morindoides.

Two phenylpropanoid-conjugated iridoids, deglucosyl gaertneroside (1) and morindoidin (2), were isolated from the leaves of Morinda morindoides (Rubiaceae) by activity-guided fractionation using an anti-malarial activity assay. The known related iridoids molucidin (3) and prismatomerin (4), two lignans, abscisic acid, two megastigmanes, and two flavonol glycosides were also identified. The structures of isolated compounds were elucidated using spectroscopic analysis. The isolated compounds were evaluated for anti-malarial activity against the chloroquine/mefloquine-sensitive strains of Plasmodium falciparum together with cytotoxicity against adult mouse brain cells. Potent anti-malarial activity of 3 and 4 (IC50 of 0.96 and 0.80 µM, CC50 of 1.02 and 0.88 µM, and SI of 1.06 and 1.10, respectively) was shown, while new iridoids 1 and 2 and pinoresinol (5) displayed moderate activity (IC50 of 40.9, 20.6, and 24.2 µM) without cytotoxicity (CC50 > 50 µM). These results indicate that 1-5 may be promising lead compounds for anti-malarial drugs. In addition, our results imply the necessity of the quality control of the extract of M. morindoides leaves based on the contents of 1-5 in terms of the safety and efficacy.

Exploring association between MBL2 gene polymorphisms and the occurrence of clinical blackwater fever through a case-control study in Congolese children.

BACKGROUND: Blackwater fever (BWF), one of the most severe and life-threatening forms of falciparum malaria, is characterized by acute massive intravascular haemolysis, often leading to acute renal failure. Thus far, the genetics of the underlying susceptibility to develop BWF is not fully elucidated. Deficiency in the MBL protein, an important component of the innate immune system, has previously been suggested to be a susceptibility factor for the development of severe malaria. This study aimed to evaluate the association between MBL2 gene polymorphisms, known to affect the MBL protein level/activity, and the occurrence of BWF among Congolese children. METHODS: This is a case-control study. Cases were patients with BWF, whereas controls, matched for gender and age, had uncomplicated malaria (UM). Dried blood spot was collected for genotyping. RESULTS: A total of 129 children were screened, including 43 BWF and 86 UM. The common allele in BWF and UM was A, with a frequency of 76.7 and 61.0%, respectively (OR: 2.67 (0.87-829) and p = 0.079). The frequency of the C allele was 18.6 and 29.1% in BWF and UM groups, respectively, with p = 0.858. Not a single D allele was encountered. Genotype AA was at higher risk for BWF whereas genotypes A0 (AB and AC) were over-represented in UM group (OR: 0.21 (0.06-0.78)) with p = 0.019. Nine haplotypes were observed in this study: 3 high MBL expression haplotypes and 6 low MBL expression haplotype. One new haplotype HYPC was observed in this study. None of these haplotypes was significantly associated with BWF. CONCLUSION: This pilot study is a preliminary research on MBL2 gene and infectious diseases in DRC. The study results show a higher risk for BWF in AA. This suggests that future studies on BWF should further investigate the contribution of a strong immune response to the occurrence of BWF.

Severe malaria in children: A descriptive report from Kinshasa, the Democratic Republic of Congo.

The decline of susceptibility of Plasmodium falciparum to chloroquine and sulfadoxine-pyrimethamine resulted in the change of drug policy. This policy has probably changed the facies of the severe form of malaria. A prospective study was conducted in Kinshasa, the Democratic Republic of Congo. Data on children aged ≤13 years, diagnosed with severe malaria were analyzed. In total, 378 children were included with an overall median age of 8 years (age range: 1-13 years). Dark urine was seen in 25.1% of cases. Metabolic acidosis (85.2%), hypoglycemia (62.2%) and hemoglobin ≤5 g/dl (39.1%) were the common laboratories features. Severe malaria anemia, cerebral malaria and Blackwater fever (BWF) were found in 39.1, 30.1 and 25.4%, respectively. Mortality rate was 4%. BWF emerges as a frequent form of severe malaria in our midst. Availing artemisin-based combination treatments in the health care system is a priority to reduce the incidence of BWF in our environment.

Black water fever associated with acute renal failure among Congolese children in Kinshasa.

Acute renal failure (ARF) is reported in some severe forms of malaria such as black water fever (BWF). It is associated with a high mortality rate and can be managed effectively with adequate renal replacement. A prospective survey of children with dark urine after a malarial infection with Plasmodium falciparum was coupled with a chart review study of patients managed in the past 11 years in the Pediatrics' Kinshasa University Hospital. Eighty-nine cases of ARF were identified, but data from only 63 patients were available, of whom 44 (69.8%) had severe malaria (39 with BWF and 5 with cerebral malaria). The mean age of the patients was 8.2±1.73 years. Of the 39 cases of BWF, an association with quinine ingestion was observed in 32 children (82%). Urea and creatinine levels were elevated in all cases (135.4±88.2 and 3.83±2.81 mg/dL, respectively). Oligo-anuria was observed in 44.4%, severe metabolic acidosis (bicarbonate<15 mEq/L) in 61.5% and hyponatremia (<130 mEq/L) in 33.3%. Peritoneal dialysis was required in 36 patients, including 20 with BWF. The remaining patients were managed with conservative treatment. Twenty-eight children (44.4%), including 20 on dialysis, fully recovered and 14 died (22.2%), including eight cases of BWF. Our study suggests that ARF is commonly associated with BWF in Congolese children. Elevated urea and creatinine and severe metabolic acidosis were observed more often than other clinical/metabolic disturbances. Severe renal impairment remains a significant complication with a high mortality rate in low-resource settings.

Prevalence of sickle cell disease in a pediatric population suffering from severe infections: a Congolese experience.

Neonatal screening for sickle cell anemia is not a common practice in the Democratic Republic of Congo (DRC). Children with sickle cell disease are known to have an increased risk of infections. We conducted a pilot study to determine the prevalence of sickle cell anemia during episodes of severe infection. A prospective study was conducted from July 2009 to July 2011. The study sites included four public hospitals at Kinshasa, DRC. The study population was selected from the source population using three-stage sampling. A total of 247 children with severe infection were consecutively recruited and screened for sickle cell disease. There were 124 boys (50.2%) and 123 girls (49.8%) with a sex-ratio of 1:1. More than two-thirds of patients (66.0%) were children between 1 and 24 months of age. Among these 247 children, 19 (7.7%) were homozygous sickle cell anemia patients (Hb SS). No patient had received Hemophilus influenzae, streptococcus pneumoniae and salmonella sp vaccines. Sepsis was the most common form of severe infection observed in 44.5% of patients. A total of 19 (7.7%) positive blood cultures were recorded. Most cases were reported in sickle cell patients (15.8%) compared to 6.1% in children who were negative for Hb S [ß6(A3)Glu→Val; HBB: c.20A>T] (p > 0.05). Of 247 children with severe infection, approximately 8.0% carried unknown sickle cell anemia mutations. Based on the findings in this study, opportunistic testing for sickle cell anemia is possible and worthwhile in children who present with severe infection in DRC until neonatal screening is universal.

Blackwater fever in Congolese children: a report of clinical, laboratory features and risk factors.

BACKGROUND: Blackwater fever (BWF) is one of the severe forms of malaria. This complication was first described among non-immune European expatriates in the malaria endemic areas. Recently, resurgence of this form of malaria has been reported among the indigenous populations. The objective of this study was to investigate the risk factors among BWF patients. METHODS: A case-control study was conducted between in four hospitals located in Kinshasa, Democratic Republic of Congo from January 2010 to December 2011. One hundred and twenty nine children were recruited with 43 (cases) and 86 (control). RESULTS: No significant difference in the gender and age distribution was observed between the case and control). The sex-ratio male to female in the case group and control group was respectively 1:1.0 and 1:1.1. The mean age was 8.62 years (SD = 3.84) in patients with haemoglobinuria and 8.55 years (SD = 3.77) in the control group. No difference in frequency of co-infection with Plasmodium falciparum and Plasmodium malariae was observed between the two groups. Significant differences in haemoglobin, haematocrit, creatinine, urea and platelets levels were observed between the two groups (p < 0.001), but not for blood group and lactate dehydrogenase (LDH) level. Majority of the BWF cases occurred during the rainy season (88.4%). Treatment with quinine (95.3%) was significantly associated with cases (p < 0.001). Seven (16.2%) of the haemoglobinuric children developed acute renal failure. CONCLUSION: Rainy season, low parasitaemia and quinine ingestion were the major risk factors significantly associated with haemoglobinuria. Acute renal failure was observed as the major complication of BWF.