Abstract:
Herbal medicines constitute a potentially important resource for new and safe drugs for the
management of microbial infections and other diseases. In this study, dichloromethane, ethylacetate and
ethanol extracts of Canarium schweinfurthii Engl., Dissotis brazzae Cong., Iboza urticifolia (Bak) E.A.Bruce, Isoglosa
lacteal Lindau, Strombosia Scheffleri Engl., and Whitfieldia elongate T. Anders were tested for antimicrobial
activity and brine shrimp toxicity. The objective was to validate claims that they are used to treat bacterial
infections, diarrhoea and heal wounds among the Haya tribe of north-western Tanzania. At least one extract
of each plant showed antibacterial activity. Dichloromethane extracts were the most active while ethanol
extracts were the least active. Extracts of Whitfieldia elongate and Isoglossa lacteal were the most and least active
with MICs in the range 0.08-0.62 mg/ml and 15.6-62.5 mg/ml, respectively. The dichloromethane extract of
Whitfieldia elongate exhibited strong antifungal activity against Cryptococcus neoformans. Against brine shrimp
larvae, the extracts from the six plants exhibited a low to very low toxicity with LC50 values ranging from
15.35-374.0µg/ml. However, ethanol extracts of Dissotis brazzae and Strombosia scheffleri had LC50 values of
>1000µg/ml. The seemingly innocuous nature and relatively good antibacterial activity against skin infections
and gastrointestinal pathogenic bacteria support the traditional uses of the plants and deserve more detailed
studies.
