RESUMEN
BACKGROUND: Although there is increased acceptance and utilization of medicinal plants worldwide, many are used indiscriminately without recourse to any safety test. Thus, the need for toxicity tests to determine the safe dose for oral consumption. OBJECTIVE: LD50 and phytochemistry of four medicinal plants of West Africa were investigated. METHODS: Thirty male and non pregnant female Swiss albino mice weighing 20grams each were used for this study. They were divided into the Control (C), Oldenlandia corymbosa L. aqueous leaf-extract treated (OCG), Parquetina nigrescens aqueous leaf extract treated (PNG), Hybanthus enneaspermus aqueous leaf extract treated (HEG), Ficus carica leaf extract treated (FCG) and Sesamum indicum aqueous seeds extract treated group (SIG). Each group except the control was further divided into four sub-groups of six mice each, and were administered orally, graded doses (SI; 1, 2, 4 and 8, PN; 2.5, 5, 10 and 20, OC; 5, 10, 20 and 40, FC; 1, 2, 4 and 8, HE; 4, 8, 16, 32) of the aqueous extract of each plant (g/kg body weight) after 12 hours fasting. RESULTS: The dry aqueous leaf extracts of HE, OC, PN, FC all have dark brown colour and pH ranging from 6.1 to 7.2 while the seed extract of SI has a light brown color with pH of 7.0. Flavonoids, cardiac glycosides, anthocyanosides, saponin, and reducing sugar were present in all extracts, while cyanogenic glycoside was present only in HE. LD50 determination results obtained using Thompson and Finney methods were as follows; OC; 14.14 +/- 0.27 and 10.56 +/- 0.20, PN; 12.60 +/- 0.10 and 13.10 +/- 0.10, HE; 8.14 +/- 0.30 and 8.24 +/- 0.35, FC; 3.36 +/- 0.26 and 4.00 +/- 0.04, SI; 4.00 +/- 0.10 and 3.10 +/- 0.22 respectively (LD50 values are in g/kg body weight. CONCLUSION: The results of this study have provided an oral LD50 from where a safe dose can be chosen for further research into the merits of the consumption of these medicinal plants.