No abstract

The swallowing of entire leaves by apes across Africa without chewing has been observed for over 40 plant species. Here we add evidence for (a) a new site, LuiKotale where leaf-swallowing of Manniophyton fulvum (Euphorbiaceae) is observed in bonobos, (b) a so far unreported ingestion of unchewed stemstrips of M. fulvum, we name stemstrip-swallowing; and (c) a test of some of the requirements put forward by Huffman for the assessment of plants ingested for medical purpose. As ecological correlates we analyzed M. fulvum phenological data and examined 1,094 dung piles collected between 2002 and 2009. By that we assessed availability and choice of leaves. In addition, we provide the first full description of the behavior related to this plant species' use by chimpanzees or bonobos using 56 bouts of M. fulvum ingestion observed between October 2007 and February 2010. With these data we tested and met 4 of the 6 requirements given by Huffman, supporting ingestion of this species as self-medication. Despite species' year-round availability and abundance, M. fulvum was ingested only at specific times, in very small amounts, and by a small proportion of individuals per party. In the absence of our own parasitological data, we used M. fulvum swallowing as evidence for parasite infestation, and seasonality as a proxy for stressors underlying seasonal fluctuation and impacting immune responses. Using these indirect factors available, we investigated conditions for a parasite to develop to its infective stage as well as conditions for the host to cope with infections. Both rain and temperature were good predictors for M. fulvum ingestion. We discuss the use of M. fulvum with respect to its hispidity and subsequent purging properties and provide insight into its ethnomedicinal uses by humans, stimulating speculations about potentially additional pharmacological effects.

These results may explain at least in part the traditional use of this plant species against parasitic diseases such as malaria in DR Congo.

Manniophyton fulvum Muell. Arg (Euphorbiaceae), is used for wound healing, inflammatory conditions and against dysentery, and diarrhea in central Africa. In addition, the plant is an important delicacy for the pygmy chympanzee (Pan paniscus). Up to now, no scientific proof exists to justify such practices. To unravel the rationale behind the folkloric uses, the leaves of the plant were extracted in methanol and chemically analysed for its secondary metabolites. The crude methanolic extract was assayed for its anti-oxidant activity using 2,2-diphenyl-1picrylhydrazyl hydrate:DPPH assay and for its anti-inflammatory potential using hens' eggs test-chorioallantoic membrane assay: HET-CAM. The crude methanolic extract showed a significant anti-oxidant activity (IC 50 : 1.06 µg/ml) as well as a strong dose dependent anti-inflammatory activity (92% inhibition at 250 µg/pellet). Via bio-assay fractionation, the main activity can be enriched in the medium polar fraction. Interestingly, no embryotoxic effects and or membrane irritation was observed in the purified fraction. These results clearly demonstrate the rationale behind the uses of this plant against the ascribed ailments, both by the traditional medical practitioners (TMP) in Africa and by Pan paniscus as a food component.

The aim of this study was to evaluate the antimalarial efficacy and the acute toxicity of the 80% ethanol extracts of Enantia olivacea, Garcinia punctata and Massularia acuminata stem barks. The in vivo antimalarial efficacy of these extracts was investigated alone or in combination by the 4-day suppressive test. To assess the acute toxicity, mice were treated with a single oral dose of each individual (2,000 mg/kg) and combined extract (≤ 1,200 mg/kg). During 7 days, the animals were observed for any clinical signs of toxicity, changes in body weight and mortality. At 200 mg/kg, Enantia olivacea, Garcinia punctata and Massularia acuminata extracts resulted, respectively, in 57.2 %, 45.3 % and 32.6 % reduction of parasitemia in mice. The combination therapy of Enantia olivacea, Garcinia punctata and Massularia acuminata (50 and 200 mg/kg of each extract) showed increased protection and survival rate associated with a significant delay of recrudescence compared with each monotherapy. No acute toxicity was observed in all the treated mice, and the 50 % lethal dose of the combined extract was assumed to be > 1,200 mg/kg. These results can partly support the use of these three plant parts for the treatment of uncomplicated malaria in Congolese traditional medicine.