An Ethnobotanical And Chemical Study Of The Poisonous Plants Of Busoga District In Uganda.
Abstract
This project was an ethnobotanical survey of the
poisonous plants of Busoga district in Uganda. The
information was gained through a questionnaire. A total
of 74 species of poisonous plants in 64 genera and 34
families were recognised in this study to be of use in
10 principal purposes by the people of Busoga. Of these,
2 species are utilised for only one purpose while 72 are
used in more than one way. These include: medicinal,
material - cultural usage, ornamental, wood fuel, food,
building/construction, live fencing, magico -
religious, forage and insecticidal uses. These plants
were collected and preserved as voucher specimens in the
herbaria (Makerere and Nairobi University). Local names
have been given in two main languages of Lusoga and
Ateso. Their taxonomic descriptions and some
illustrations have also been given.
Crude ethanol extracts of twelve of the plants
investigated were used on Artemia sa7ina (brine shrimp)
tests at different concentrations in quardruplicates.
The number-of brine shrimp nauplii surviving in each .
vial were counted every 4 houFB for 24 hours. The LC50
of these extracts were computed by use of probit
analysis technique after Finney (Delaunois,1973) using
the statistical software(MSTATC). Out of the 12 extracts
bioassayed, 9 of them showed LC50 of less than or equal
to 0.2 umgl-1 with those of Tacca 7eonetopeta7oides and
G7adio7us nata7ensis showing LC50 of 0.03ugml-1
respectively. Three had LC -1 50 of 0.6 up to 0.9 ugml .
The lethalities of these extracts towards brine shrimp
larvae at low concentrations showed that they were
physiologically active thus being poisonous.
Twenty two spec i es in different families had some
of their parts such as: corms, root and stem barks,
leaves and bulbs chemically analysed in an effort to
identify the principal secondary metabolites. The main
compounds identified included: alkaloids, saponins,
flavonoids, anthraquinones, sterols and triterpenes.
These were found to occur in different concentrat ions
thus a further evidence that they are poisonous. The
leaves of capparis tomentosa, A 77amanda neiriifolium,
stem bark of P 7umer ia acut ifo 7ia, bu 1bs of Scadoxus
mu7tif7orus and Tacca 7eonetopeta7oides showed high
alkaloid content. Anthraquinones were highest in the
members of the family Leguminosae. For saponins, they
were more abundant in the corms of Dioscorea bu7bifera,
Scadoxus multiflorus and Gladiolus natalensis.
Citation
Master of Science in BotanyPublisher
University of Nairobi Department of Botany