Testing Beyond Ethnomedical Claims: Brine Shrimp Lethality of Some Tanzanian Plants

Extracts of 34 plants that are traditionally used for the treatment of different diseases exhibited various degrees of toxicity on brine shrimp. The concentration killing 50% (LC sub(50)) of the shrimps was below 50 mu g/ml for 14 (41.2%), 50-100 mu g/ml for 10 (29.4%), and greater than 100 mu g/ml for 10 (29.4%) of the plants, respectively. Dalbergia nitidula (LC sub(50) 0.87 mu g/ml), Ozoroa insignis (LC sub(50) 2.21 mu g/ml), Markhamia obtusifolia (LC sub(50) 8.94 mu g/ml), Ximenia caffra (LC sub(50) 11.25 mu g/ml), Croton macrostachys (LC sub(50) 13.40 mu g/ml), and Mormodica calantha (LC sub(50) 19.38 mu g/ml) were the most toxic. The results indicate the possibility that some of the plant extracts may be toxic or contain useful cytotoxic compounds, which was not reported by the traditional healers.