John M. Kasenene

Novel Antimalarial Compounds Isolated in a Survey of Self-Medicative Behavior of Wild Chimpanzees in Uganda

ABSTRACT Following a veterinary and behavioral survey of chimpanzees from a natural population in Uganda, leaf samples of Trichilia rubescens were collected because of the unusual method of ingestion observed. The methanolic crude extract of T. rubescens leaves exhibited significant antimalarial activity in vitro. Bioassay-directed fractionation provided two new limonoids, trichirubines A and B. A greater understanding of the role of secondary compounds in the primate diet may be helpful in recovering naturally occurring compounds of medicinal significance for human medicine.

Tropical forest management: can rates of natural treefalls help guide us?

Only a small percentage of tropical forests are legally protected and so, if we are to conserve tropical forest species we must encourage sustainable exploitation of unprotected forest areas. Selective timber harvesting is frequently cited as a sustainable use of tropical forests and the authors studied the effects of this kind of exploitation on natural treefall rates, an important regulative process, in the Kibale Forest, Uganda. Their results indicate that levels of destruction typical of capital intensive mechanised timber harvesting seriously disrupt the dynamic balance of the forest. They discuss alternative methods for selective timber harvesting that would be less disruptive and present an objective method which may help rain forest managers determine which multiple-use options are compatible with rain forest conservation.

Traditional plants used for medicinal purposes by local communities around the Northern sector of Kibale National Park, Uganda

ETHNOPHARMACOLOGICAL RELEVANCE The study was done to establish medicinal plants used in the treatment of various diseases by the people in the Northern sector of Kibale National Park in western Uganda. It was also aimed at establishing the plant parts used and the mode of preparation of remedies. These plants create a basis for phytochemical evaluation which can lead to the discovery of biologically active compounds that can be used as starting materials in the development of new drugs targeting selected diseases such as malaria. MATERIALS AND METHODS The required information was obtained using open interviews, semi-structured questionnaires, focus group discussions and transect walks. RESULTS Different medicinal plants (131 species) distributed over 55 families were observed to be used by the local communities around the Northern sector of Kibale National Park. The plants as reported in this paper are used to treat 43 physical illnesses/diseases. The most used parts of the plants are the leaves. Water is the main medium used for the preparation of the remedies which are mostly administered orally. CONCLUSION The people in the study area have a rich heritage of traditional plants that are used in the health care system to treat diseases. These medicinal plants have contributed significantly to several disease therapies. The most common diseases treated are malaria and cough, which are mostly treated by Vernonia amygdalina Del. and Albizia coriaria Welw. respectively. The main sources of medicinal plants include bush land, home gardens, grasslands, and the forest.

Nodular Worm Infection in Wild Chimpanzees in Western Uganda: A Risk for Human Health?

This study focused on Oeosophagostomum sp., and more especially on O. bifurcum, as a parasite that can be lethal to humans and is widespread among humans and monkeys in endemic regions, but has not yet been documented in apes. Its epidemiology and the role played by non-human primates in its transmission are still poorly understood. O. stephanostomum was the only species diagnosed so far in chimpanzees. Until recently, O. bifurcum was assumed to have a high zoonotic potential, but recent findings tend to demonstrate that O. bifurcum of non-human primates and humans might be genetically distinct. As the closest relative to human beings, and a species living in spatial proximity to humans in the field site studied, Pan troglodytes is thus an interesting host to investigate. Recently, a role for chimpanzees in the emergence of HIV and malaria in humans has been documented. In the framework of our long-term health monitoring of wild chimpanzees from Kibale National Park in Western Uganda, we analysed 311 samples of faeces. Coproscopy revealed that high-ranking males are more infected than other individuals. These chimpanzees are also the more frequent crop-raiders. Results from PCR assays conducted on larvae and dried faeces also revealed that O. stephanostomum as well as O. bifurcum are infecting chimpanzees, both species co-existing in the same individuals. Because contacts between humans and great apes are increasing with ecotourism and forest fragmentation in areas of high population density, this paper emphasizes that the presence of potential zoonotic parasites should be viewed as a major concern for public health. Investigations of the parasite status of people living around the park or working inside as well as sympatric non-human primates should be planned, and further research might reveal this as a promising aspect of efforts to reinforce measures against crop-raiding.

PLANTS FOR MALARIA TREATMENT IN SOUTHERN UGANDA: TRADITIONAL USE, PREFERENCE AND ECOLOGICAL VIABILITY

ABSTRACT A study on ethnomedicinal use, preference for species, and ecological viability of plants used for treating malaria was carried out among the communities living around the Sango Bay Forest Reserve in southern Uganda. Semi-structured interviews and informal discussions were used to collect ethnobotanical information. Abundance and demographic patterns of the key forest tree species used to treat malaria were determined, using 45 plots of 0.1 ha. Sixteen species representing 11 families and 14 genera were reportedly used to treat malaria, including four new reports. Hallea rubrostipulata (K. Schum.) J.-F.Leroy, Warburgia ugandensis Sprague, and Syzygium guineense (Willd.) DC. were the most important forest tree species used to treat malaria and were chosen for further study. The three species were found to be highly valued in the treatment of malaria and similarly used by the local people as determined by the clustering procedure. The species generally had an inverse J-shaped curve in their population structures, indicating viable regenerating populations. The recognition of the use of traditional medicine by the local communities as an integral and essential part of their health care system is vital in the conservation and sustainable utilization of these plants.

Antiplasmodial and cytotoxic activities of medicinal plants traditionally used in the village of Kiohima, Uganda.

AIM OF THE STUDY In Uganda, malaria is the most common disease and Ugandan people largely rely on traditional medicine. In this context, we carried out an ethnobotanical study on the Kiohima village, located close to the Kibale National Park in South-Western Uganda and investigated in vitro the antiplasmodial and cytotoxic activities of selected medicinal plants. MATERIALS AND METHODS Seventy-five plants-using adults (men and women) were interviewed to find out their plant use. From these information, 48 plants used in traditional medicine were identified and according to their reported uses and to bibliographic data, several parts of 28 plants (leaves, barks, roots), were selected and collected for biological evaluations. These samples were dried, extracted with ethyl acetate and the crude extracts were assayed for in vitro antiplasmodial and cytotoxic activities at 10 μg/mL. RESULTS One third of the screened plants showed a significant antiplasmodial activity with inhibition greater than 50% at 10 μg/mL. CONCLUSION These results may indicate a possible explanation of the use of some medicinal plant against malaria in the village of Kiohima and have also allowed to highlight a plant with potent antimalarial activity: Citropsis articulata root barks.

Structure and in vitro antiparasitic activity of constituents of Citropsis articulata root bark.

From the results of an ethnomedicinal investigation of plants from Uganda with antimalarial activity, Citropsis articulata was selected because of the antiplasmodial effect of an ethyl acetate extract of its root bark. Thus, from the cyclohexane, ethyl acetate, and methanol extracts, two new heterocyclic compounds, omubioside (1) and katimborine (2), were isolated in addition to five known coumarins (rutarin (3), seselin (4), suberosin (5), demethylsuberosin (6), and haploperoside (7)), two known alkaloids (5-hydroxynoracronycine (8) and 1,5-dihydroxy-2,3-dimethoxy-10-methyl-9-acridone (9)), trigonelline (10), and the limonoid 7α-obacunyl acetate (11). The best growth inhibitors of Plasmodium falciparum were alkaloids 8 and 9, with IC50 values of 0.9 and 3.0 μg/mL.

Hydroperoxy-cycloartane triterpenoids from the leaves of Markhamia lutea, a plant ingested by wild chimpanzees

In the framework of the phytochemical investigation of plant species eaten by wild chimpanzees in their natural environment in Uganda, leaf samples of Markhamia lutea were selected and collected. The crude ethyl acetate extract of M. lutea leaves exhibited significant in vitro anti-parasitic activity and low cytotoxicity against MRC5 and KB cells. Fractionation of this extract led to six cycloartane triterpenoids, musambins A-C and their 3-O-xyloside derivatives musambiosides A-C. The structures were elucidated on the basis of spectral studies including mass spectroscopy and extensive 2D NMR. Most of the compounds exhibited mild anti-leishmanial and anti-trypanosomal activities.

Suitable Habitats for Endangered Frugivorous Mammals: Small-Scale Comparison, Regeneration Forest and Chimpanzee Density in Kibale National Park, Uganda

Landscape patterns and chimpanzee (Pan troglodytes schweinfurthii) densities in Kibale National Park show important variation among communities that are geographically close to one another (from 1.5 to 5.1 chimpanzees/km2). Anthropogenic activities inside the park (past logging activities, current encroachment) and outside its limits (food and cash crops) may impact the amount and distribution of food resources for chimpanzees (frugivorous species) and their spatial distribution within the park. Spatial and temporal patterns of fruit availability were recorded over 18 months at Sebitoli (a site of intermediate chimpanzee density and higher anthropic pressure) with the aim of understanding the factors explaining chimpanzee density there, in comparison to results from two other sites, also in Kibale: Kanyawara (low chimpanzee density) and Ngogo (high density, and furthest from Sebitoli). Because of the post-logging regenerating status of the forest in Sebitoli and Kanyawara, smaller basal area (BA) of fruiting trees most widely consumed by the chimpanzees in Kanyawara and Sebitoli was expected compared to Ngogo (not logged commercially). Due to the distance between sites, spatial and temporal fruit abundance in Sebitoli was expected to be more similar to Kanyawara than to Ngogo. While species functional classes consumed by Sebitoli chimpanzees (foods eaten during periods of high or low fruit abundance) differ from the two other sites, Sebitoli is very similar to Kanyawara in terms of land-cover and consumed species. Among feeding trees, Ficus species are particularly important resources for chimpanzees at Sebitoli, where their basal area is higher than at Kanywara or Ngogo. Ficus species provided a relatively consistent supply of food for chimpanzees throughout the year, and we suggest that this could help to explain the unusually high density of chimpanzees in such a disturbed site.

Post-logging tree mortality and major branch losses in Kibale Forest, Uganda

Abstract This study was undertaken to establish whether selective felling and the existence of large forest gaps influence the dynamics of tree and branch falls. Censuses of fallen trees and large branch falls in uncut, lightly cut and heavily cut forest tracts were conducted for 20 months. Dead-standing trees in the study compartments were enumerated only three times at 6-month intervals. In lightly cut forest, the densities of live and dead tree and branch falls were similar but monthly tree snaps were more than uproots. However, for heavily cut forest, total tree falls (snap + uproot) involved more live than dead trees. There were more live than dead tree snaps and the rate of tree uproots was low. in contrast to the above, the density of tree snaps and uproots in uncut mature forest was similar. For total tree falls and live tree or large branch falls, the heavily selectively cut forest exhibited higher rates than uncut and lightly cut forest tracts. The annual rates of live tree falls ha −1 were 1.30 for lightly cut, 3.30 for heavily cut and 1.74 for uncut mature forest. It appears that heavy logging increases tree mortality rates through falls where more live tree snaps than uproots are involved.