Abstract:
Aims: This study has evaluated ethanol extracts from five medicinal plants selected
through ethnobotanical study from Lake Victoria basin, Tanzania for their in vitro antimycobacterial
activity against two Mycobacterium species and cytotoxicity against brine
shrimp larvae.
Study Design: Laboratory experimental tests.
Place and Duration of Study: Institute of Traditional Medicine, Muhimbili University of
Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, Tanzania, between July
2010 and July 2011.
Methodology: Five medicinal plants were selected from the priority list obtained from
Lake Victoria basin, Tanzanian side. Collection, processing and drying of plant samples
were done in the field with the assistance of a botanist while extraction and concentration
of plant samples to obtain crude extracts were done in the laboratory following standard
procedures. The plants included in this study are Antidesma membranaceum,
Crassocephalum manii, Entada abyssinica, Croton dichogamus and Rubia cordifolia. The
two fold microdilution method was used to determine the MIC values of extracts againsttwo Mycobacterium marker strains (Mycobacterium indicus pranii and Mycobacterium
madagascariense). The cytotoxicity of plant extract was evaluated against brine shrimp
larvae. Furthermore, the extracts were screened phytochemicaly to establish the group of
compounds responsible for the activity.
Results: Among the tested extracts, the stem bark of A. membranaceum and C. manii
showed moderate to mild activity against M. indicus pranii (MIC = 0.3125 mg/ml) and M.
madagascariense (MIC = 0.625 mg/ml) respectively. Furthermore, A. membranaceum
exhibited significant toxicity activity with LC50 value of 36.134 μg/ml against brine shrimp
larvae. Other plants were moderately active when tested in vitro against the above
organisms. Phytochemical screening of extracts indicated the presence of different
classes of compounds.
Conclusion: This study has shown the potential of the priority medicinal plant extracts to
be the source of possible lead compounds and anti‐TB drug candidates needed for the
management of Tuberculosis. Isolation of active principles from active fractions will be
further undertaken.
