In vitro antiprotozoal activity and cytotoxicity of extracts and isolated constituents from Greenwayodendron suaveolens.

ETHNOPHARMACOLOGICAL RELEVANCE: The Nkundo people (Nkundo area of Bolongo, Mai-Ndombe district, Bandundu Province, DR Congo) use various plant parts of the tree Greenwayodendron suaveolens (Engl. & Diels) Verdc. (syn. Polyalthia suaveolens Engl. & Diels) (Annonaceae) against malaria, but its antiprotozoal constituents are not known. MATERIALS AND METHODS: The crude 80% ethanol extract from the fruits, leaves, root bark and stem bark and 16 fractions were assessed in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum (Pf-K1). Their cytotoxic effects were evaluated against MRC-5 cells. Active constituents were isolated by chromatographic means, identified using spectroscopic methods, and evaluated in the same assays. RESULTS: The root bark extract showed the highest activity against P. falciparum K1 (IC50 0.26µg/mL) along with the stem bark alkaloid fraction (IC50 0.27µg/mL). The root bark alkaloid fraction had a pronounced activity against all selected protozoa with IC50 values <1µg/mL. The 90% methanol fractions of the different plant parts showed a pronounced activity against P. falciparum K1, with IC50 values ranging between 0.36µg/mL and 0.69µg/mL. Four constituents were isolated: the triterpenes polycarpol, and dihydropolycarpol, the latter one being reported for the first time from nature, and the alkaloids polyalthenol and N-acetyl-polyveoline. They were active to a various degree against one or more protozoa, mostly accompanied by cytotoxicity. The highest selectivity was observed for N-acetyl-polyveoline against P. falciparum K1 (IC50 2.8µM, selectivity index 10.9). CONCLUSIONS: These results may explain at least in part the traditional use of this plant species against parasitic diseases such as malaria in DR Congo.

In vitro antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Isolona hexaloba.

ETHNOPHARMACOLOGICAL RELEVANCE: Isolona hexaloba (Pierre) Engl. and Diels (Annonaceae) is traditionally used in D.R. Congo against parasitic diseases including malaria. MATERIALS AND METHODS: Two crude aqueous extracts, 3 crude methanol extracts and 3 crude 80% ethanol extracts from the leaves, root bark and stem bark together with 12 subfractions from the crude 80% ethanol extracts were evaluated in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum and the chloroquine and pyrimethamine resistant K1 strain of Plasmodium falciparum. Their cytotoxic effects against MRC-5 cell lines were also assessed. RESULTS: Results indicated that the most pronounced activities against T. b. brucei were recorded for the crude methanol extracts of root bark (IC50=1.97 µg/ml; SI>32.49) and leaves (IC50=2.65 µg/ml; SI>24.15). Three samples displayed good activity against T. cruzi: the 80% methanol extract of leaves (IC50=8.33 µg/ml; SI>3.92), its petroleum ether fraction (IC50=8.50 µg/ml; SI=2.52) and the crude aqueous extract of the stem bark (IC50=9.31 µg/ml; SI=3.46). The crude aqueous extract of the leaves exhibited a pronounced and selective activity against L. infantum (IC50=2.00 µg/ml; SI>32). The crude methanol extract of leaves (IC50=6.35 µg/ml; SI>10.10) and the 2 dichloromethane soluble fractions of the 80% ethanol extracts from root bark (IC50=6.96 µg/ml; SI=6.1) and stem bark (IC50=8 µg/ml; SI>8.00) showed good activity and selectivity against L. infantum. The most active samples against Plasmodium falciparum K1 were the leaves crude 80% ethanol extract (0.92 µg/ml) and its fractions: alkaline aqueous (IC50=0.27 µg/ml), 90% methanol (0.90 µg/ml) and dichloromethane (1.04 µg/ml), respectively, with promising selectivity indexes of 35

In vitro antiprotozoal and cytotoxic activity of 33 ethonopharmacologically selected medicinal plants from Democratic Republic of Congo.

ETHNOPHARMACOLOGICAL RELEVANCE: The antiprotozoal and cytotoxic activity of the aqueous extracts from 33 medicinal plants, used by traditional healers for the treatment of various parasitic diseases and collected after an ethnopharmacological inventory conducted in the Bolongo area, Bandundu province in DR Congo, was evaluated. MATERIALS AND METHODS: Decoctions were prepared, lyophilized and evaluated for in vitro antiprotozoal activity against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum, and the chloroquine- and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Cytotoxicity against MRC-5 cells was included to assess selectivity of activity. RESULTS: Most of the tested extracts exhibited pronounced (IC(50)≤5µg/ml) or good (5

Use and function of genital contacts among female bonobos.

Female bonobos, Pan paniscus, show a mounting behaviour that differs physically from that in other primate species. They embrace each other ventroventrally and rub their genital swellings against each other. We investigated five hypotheses on the function of ventroventral mounting (genital contacts) that derive from previous studies of both primate and nonprimate species: (1) reconciliation; (2) mate attraction; (3) tension regulation; (4) expression of social status; and (5) social bonding. We collected data in six field seasons (1993-1998) from members of a habituated, unprovisioned community of wild bonobos at Lomako, Democratic Republic of Congo. No single hypothesis could account for the use of genital contacts, which appeared to be multifunctional. We found support for hypotheses 1 and 3. Rates of postconflict genital contacts exceeded preconflict rates suggesting that the display is used in the context of reconciliation. Rates of genital contacts were high when food could be monopolized and tension was high. However, genital contacts also occurred independently of agonistic encounters. Our study shows rank-related asymmetries in initiation and performance of genital contacts supporting the social status hypothesis: low-ranking females solicited genital contacts more often than high-ranking females while the latter were more often mounter than mountee. Although subordinates took more initiative to achieve genital contact, dominants mostly responded to the solicitation (ventral presentation) with mounting, indicating that the performance benefits both individuals. We suggest that genital contacts can be used to investigate both quality and dynamics of dyadic social relationships among female bonobos. Copyright 2000 The Association for the Study of Animal Behaviour.

Intracommunity relationships, dispersal pattern and paternity success in a wild living community of Bonobos (Pan paniscus) determined from DNA analysis of faecal samples.

Differences in social relationships among community members are often explained by differences in genetic relationships. The current techniques of DNA analysis allow explicit testing of such a hypothesis. Here, we have analysed the genetic relationships for a community of wild bonobos (Pan paniscus) using nuclear and mitochondrial DNA markers extracted from faecal samples. Bonobos show an opportunistic and promiscuous mating behaviour, even with mates from outside the community. Nonetheless, we find that most infants were sired by resident males and that two dominant males together attained the highest paternity success. Intriguingly, the latter males are the sons of high-ranking females, suggesting an important influence of mothers on the paternity success of their sons. The molecular data support previous inferences on female dispersal and male philopatry. We find a total of five different mitochondrial haplotypes among 15 adult females, suggesting a frequent migration of females. Moreover, for most adult and subadult males in the group we find a matching mother, while this is not the case for most females, indicating that these leave the community during adolescence. Our study demonstrates that faecal samples can be a useful source for the determination of kinship in a whole community.

Mitochondrial sequences show diverse evolutionary histories of African hominoids.

Phylogenetic trees for the four extant species of African hominoids are presented, based on mtDNA control region-1 sequences from 1,158 unique haplotypes. We include 83 new haplotypes of western chimpanzees and bonobos. Phylogenetic analysis of this enlarged database, which takes intraspecific geographic variability into account, reveals different patterns of evolution among species and great heterogeneity in species-level variation. Several chimpanzee and bonobo clades (and even single social groups) have retained substantially more mitochondrial variation than is seen in the entire human species. Among the 811 human haplotypes, those that branch off early are predominantly but not exclusively African. Neighbor joining trees provide strong evidence that eastern chimpanzee and human clades have experienced reduced effective population sizes, the latter apparently since the Homo sapiens-neanderthalensis split. Application of topiary pruning resolves ambiguities in the phylogenetic tree that are attributable to homoplasies in the data set. The diverse patterns of mtDNA sequence variation seen in today's hominoid taxa probably reflect historical differences in ecological plasticity, female-biased dispersal, range fragmentation over differing periods of time, and competition among social groups. These results are relevant to the origin of zoonotic diseases, including HIV-1, and call into question some aspects of the current taxonomic treatment and conservation management of gorillas and chimpanzees.