In-vivo antimalarial activity of Cassia occidentalis, Morinda morindoides and Phyllanthus niruri.

The ethanolic, dichloromethane and lyophilized aqueous extracts of Cassia occidentalis root bark, Morinda morindoides leaves and whole plants of Phyllanthus niruri were evaluated for their antimalarial actvity in vivo, in 4-day, suppressive assays against Plasmodium berghei ANKA in mice. No toxic effect or mortality was observed in mice treated, orally, with any of the extracts as a single dose, of 500 mg/kg body weight, or as the same dose given twice weekly for 4 weeks (to give a total dose of 4 g/kg). No significant lesions were observed, by eye or during histopathological examinations, in the hearts, lungs, spleens, kidneys, livers, large intestines or brains of any mouse. At doses of 200 mg/kg, all the ethanolic and dichloromethane extracts produced significant chemosuppressions of parasitaemia (of > 60% for C. occidentalis root bark and Ph. niruri whole plant, and of 30% for M. morindoides leaves) when administered orally. The most active ethanolic extract, that of Ph. niruri, reduced parasitaemia by 73%. The dichloromethane extracts of M. morindoides and Ph. niruri produced similar reductions (74% and 72% chemosuppression, respectively), whereas that of C. occidentalis was slightly less active (60% chemosuppression). Each lyophilized aqueous extract was less active than the corresponding ethanolic extract.

Antiamoebic and spasmolytic activities of extracts from some antidiarrhoeal traditional preparations used in Kinshasa, Congo.

Three major extracts from some traditional preparations, based on medicinal plants, used as antidiarrhoeal agents were investigated for their putative antiamoebic and spasmolytic activities in vitro. Results indicated that both biological activities are concentrated in the polyphenolic fraction, and not in the saponin or alkaloid containing fractions. The most active polyphenolic extracts were those from Euphorbia hirta whole plant, leaves of Alchornea cordifolia, Crossopteryx febrifuga, Nauclea latifolia, Psidium guajava, Tithonia diversifolia, stem bark of Harungana madagascariensis, Mangifera indica, Maprounea africana and Psidium guajava, inhibiting Entamoeba histolytica growth with MAC < 10 micrograms/ml. The same extracts, at a concentration of 80 micrograms/ml in an organ bath, also exhibited more than 70% inhibition of acetylcholine and/or KCl solution-induced contractions on isolated guinea-pig ileum.

Antimalarial activity of 20 crude extracts from nine African medicinal plants used in Kinshasa, Congo.

Twenty extracts including ten EtOH and ten CH2Cl2 from different parts of nine African medicinal plants used in Congolese traditional medicine for the treatment of malaria, were submitted to a pharmacological test in order to evaluate their effect on P. falciparum growth in vitro. Of these plant species, 14 (70%) extracts including EtOH and CH2Cl2 from Cassia occidentalis leaves, Cryptolepis sanguinolenta root bark, Euphorbia hirta whole plant, Garcinia kola stem bark and seeds, Morinda lucida leaves and Phyllanthus niruri whole plant produced more than 60% inhibition of the parasite growth in vitro at a test concentration of 6 microg/ml. Extracts from E. hirta, C. sanguinolenta and M. morindoides showed a significant chemosuppression of parasitaemia in mice infected with P. berghei berghei at orally given doses of 100-400 mg/kg per day.

Antiamoebic and phytochemical screening of some Congolese medicinal plants.

Results from the in vitro antiamoebic activity of some Congolese plant extracts used as antidiarrhoeic in traditional medicine indicated that of 45 plant extracts tested, 35 (77.78%) exhibited an antiamoebic activity and 10 (22.22%) were inactive. The highest activity (MIC < 100 microg/ml) was obtained with extracts from root bark of Paropsia brazzeana, Cryptolepis sanguinolenta, Alchornea cordifolia, Hensia pulchella, Maprounea africana, Rauwolfia obscura and Voacanga africana, leaves and stem bark of Psidium guajava, stem bark of Dialum englerianum, Harungana madagascariensis and Mangifera indica, mature seeds of Carica papaya, and leaves of Morinda morindoides and Tithonia diversifolia. Metronidazole used as reference product showed a more pronounced activity than that of all plant extracts tested.

[Relationship between Plasmodium parasitemia and febrile episodes in various population groups in Kinshasa, Zaire]. / Relation entre parasitémie à Plasmodium et accès fébrile dans différents groupes de population à Kinshasa, Zaire.

The objective of this study was to determine the relative importance of determinants of fever-episodes in an environment with perennial malaria transmission. In 6 neighbourhoods of Kinshasa with different degrees of urbanization, 120 clusters of children younger than 10 years were selected over a one year period and followed up for 2 weeks each. In the 4,816 children retained for analysis 906 fever episodes were registered, which corresponds to an average incidence rate of 4.9 episodes per child per year. Seven hundred (77.3%) of the fever cases had a positive thick film (IF) but of the 3,289 children with a positive TF only 21.3% presented fever during the observation period. Nevertheless, high parasite densities formed, without neglecting the role of other infectious etiologies, the mayor pathogenic mechanism associated with fever. The risk for a fever episode was, in multivariate analysis, 40 times higher in children with at least one positive TF than in children with a negative TF on both day 1 and day 14, and amongst the ones with a positive TF the risk was 3 times higher in children with a parasitemia above 3,000 trophozoites/microliter blood. The habitat constituted another important independent determinant: the relative risk for fever was 1.48 for non-urbanized neighbourhoods, which probably reflects the low malaria transmission in the urbanized ones, but 2.1 for semi-urbanized against peripheral neighbourhoods, where the parasite index is high. Low socio-economic status, the short dry season and young age formed, in this order, further factors to the take into account.

Paludisme de l'enfant a Kinshasa : etude de la variation spontanee de la parasitemie chez les sujets asymptomatiques

Le present travail; dont l'objectif consiste a decrire l'evolution spontanee de la parasitemie au cours d'une infection a Plasmodium falciparum; a ete mene sur une sous-population d'enfants; ages de 0 a 10 ans vivant dans quelques quartiers de la ville de Kinshasa. Pour ce faire; un sous-echantillon de 3.194 enfants; soit 69;7 pour cent de l'effectif total qui a pu etre revu a deux occasions (jour 1 et jour 15); sans notion de medication; ni de manifestation morbide quelconque pouvant susciter la prise des medicaments durant la periode de l'etude; a ete analyse. Cinq profils d'evolution parasitemique ont ete identifies. Ces profils evolutifs decrits ne constituent somme toute qu'une vue fragmentaire des vagues parasitaires qui evoluent. Pour expliquer les faibles valeurs de parasitemies observees contrairement a ce qui est prevu par le modele de croissance geometrique; l'hypothese d'un controle immunologique de la parasitemie dont l'efficacite est variable selon l'environnement; l'age du sujet; le standing familial; la saison et la taille familiale; doit etre acceptee

[Childhood malaria in Kinshasa (Zaire). Influence of seasons, age, environment, and family social conditions]. / Le paludisme de l'enfant à Kinshasa (Zaïre). Influence des saisons, de l'âge, de l'environnement et du standing familial.

Frequency of malaria in children was evaluated from march 1986 to February 1987 in six districts of Kinshasa by paludometric survey with multiple visits. The six districts were selected according to their geographical situation and their degree of urbanisation. Each month, two stocks of children from 0 to 10 years old dwelling in a street were selected district and visited twice randomization in each selected district and visited twice at 2 weeks of interval. 5,541 children were examined at the occasion of the second visit. Influence of seasons, age, district, socio-economic level of the family and level of education of the parents was determined by analysing the following parameters: plasmodial index, parasitic density, incidence of fever attacks, conversion rate of thick smear, antimalaria drug consumption. Parasitic prevalence is 50 p.c. annual incidence of fever attacks is 50 p.c. and annual frequency of antimalaria drugs is 3,64 per child. Dry seasons (June-September and January-February) ease the pathophoresis and pathogenicity of plasmodia. The age group of less than one year is relatively less parasitized but from 2 years, contact with parasites is very high and without any significant evolution up to 10 years. The district where a child is living plays a predominant role on paludometric indices. Transmission is deeply influenced by geographical situation in the center of the town or in outlying districts and by the socio-economic environment (basic equipment, streets conditions, quality of accommodation). The socio-economic level of the child's family is also important in regard to malaria prevention. The level of education of the parents and mainly the mother has the greatest influence.

[Malaria and pregnancy. Epidemiological situation in Kinshasa (Zaïre)]. / Paludisme et grossesse. Situation épidémiologique à Kinshasa (Zaïre).

By regular blood smears to 730 women (430 pregnant women and 250 non pregnant) authors state precisely epidemiologic situation of malaria to women at Kinshasa. The prevalence of malaria of pregnant women is 22 per cent against 6.1 per cent for non pregnant adult women. Malarial infestation in gravido-puerperal period is : mother : 23.7 per cent ; umbilical cord : 3.1 per cent ; newborn : 5.4 per cent ; placenta : 10.1 per cent. Plasmodium falciparum is the principal agent of malaria at Kinshasa. Neither age, nor parity constitute risk factors of malaria. Many cases of malaria without fever exist at Kinshasa. Newborn with malaria and from pregnancies with infected placentas present at the birth a small weight. Placentas of pregnancies with malaria and infected have invariably the same weight.

Response of children with Plasmodium falciparum to chloroquine and development of a national malaria treatment policy in Zaire.

In vivo sensitivity of Plasmodium falciparum to chloroquine was evaluated in 4 of 9 regions of Zaire in 1985 to develop a national strategy for treatment of malaria. Children less than 5 years of age were treated with either a single dose of chloroquine base, 10 mg/kg, or a dose of 25 mg/kg given over 3 d. A modified 7-day World Health Organization in vivo test was used with follow-up 2, 3 and 7 d after the start of treatment. 339 children were studied. In Bwamanda 92% of children were aparasitaemic 7 days after chloroquine, 10 mg/kg, but in Kinshasa only 44% were free of parasites after 25 mg/kg chloroquine. The mean drop in parasite density among those who did not clear parasites by day 7 was greater than 98% of the initial value. Although the parasite density decreased markedly, the failure of most subjects to become aparasitaemic indicated a marked decrease in parasite sensitivity since 1983. Only one child of 51 who were initially febrile remained febrile, although 14 (28%) of these had resistant parasites. The decrease in parasitaemia and temperature, even among children with resistant strains, led the Ministry of Health to recommend 25 mg/kg chloroquine as first line treatment for fever/malaria in their national malaria control plan. The plan includes drug sensitivity surveillance and a referral system for patients who do not respond to chloroquine treatment.

[Chemoresistance of Plasmodium falciparum in Kinshasha. In vivo tests and chloroquine absorption]. / Chimio-résistance de Plasmodium falciparum a Kinshasa. Tests in vivo et absorption de chloroquine.

With the test in vivo and the bleeding dosage of chloroquine, authors report the rate of resistance of chloroquine to Plasmodium falciparum. 2.3% of Plasmodium falciparum in Kinshasa are resistant to chloroquine.