The LD(50) of roselle calyx extract and its effect on blood pressure were determined. The LD(50) was found to be above 5000 mg kg(-1). Roselle calyx infusion was found to lower significantly (p<0.05) both systolic and diastolic pressure in spontaneously hypertensive and normotensive Wistar-Kyoto rats at tested doses of 500 and 1000 mg kg(-1) body weight. The reduction in blood pressure in both groups was positively correlated with weight. Continuous consumption of the infusion at 1000 mg kg(-1) was discovered to lead to sudden death in spontaneously hypertensive rats but not in Wistar-Kyoto rats. Water intake was not significantly different (p>0.05) in the control groups of the two strains of rats used, neither was there a significant difference in their urine output. The water intake in the treated spontaneously hypertensive and normotensive rats was not different from the corresponding control groups. However the urine output of the treated spontaneously hypertensive rats was significantly higher. A significant decrease in serum creatinine, cholesterol, and glucose in the treated rats compared with the control as well as a significant increase in serum uric acid was observed. The serum proteins (albumin and total protein) in the treated rats when compared with the control groups was not changed significantly.

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The LD(50) of roselle calyx extract and its effect on blood pressure were determined. The LD(50) was found to be above 5000 mg kg(-1). Roselle calyx infusion was found to lower significantly (p<0.05) both systolic and diastolic pressure in spontaneously hypertensive and normotensive Wistar-Kyoto rats at tested doses of 500 and 1000 mg kg(-1) body weight. The reduction in blood pressure in both groups was positively correlated with weight. Continuous consumption of the infusion at 1000 mg kg(-1) was discovered to lead to sudden death in spontaneously hypertensive rats but not in Wistar-Kyoto rats. Water intake was not significantly different (p>0.05) in the control groups of the two strains of rats used, neither was there a significant difference in their urine output. The water intake in the treated spontaneously hypertensive and normotensive rats was not different from the corresponding control groups. However the urine output of the treated spontaneously hypertensive rats was significantly higher. A significant decrease in serum creatinine, cholesterol, and glucose in the treated rats compared with the control as well as a significant increase in serum uric acid was observed. The serum proteins (albumin and total protein) in the treated rats when compared with the control groups was not changed significantly.

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SummaryAn aqueous extract of defatted leaves of Azadirachta indica was found to possess trypanocidal activity against Trypanosoma brucei brucei. Column chromatography of the crude extract gave three fractions, I, II, and III, that eluted with ethylacetate/methanol, benzene/ methanol, and acetic acid/methanol, respectively. Of these extracts, only fraction III retained trypanocidal properties and cured mice chronically infected with Trypanosoma brucei brucei. Histopathological studies of the brains, livers, hearts, and spleens of the treated mice showed no cellular infiltrations. These findings are discussed in relation to trypanosome chemotherapy.

The effect of Allium sativum (Liliacea) on trypanosome-infected mice was examined. At a dose of 5.0 mg/ml, the oily extract from the pulp completely suppressed the ability of the parasites to be infective in the host. Column chromatography of the extract gave four fractions: ethylacetate/methanol, ethylacetate/ethanol, benzene/methanol, and acetic acid/methanol. Among these fractions, the acetic acid/methanol fraction retained the trypanocidal features of the crude extract. It cured experimentally infected mice of trypanosomiasis in 4 days when given at a dose of 120 mg/kg per day. The extract also manifested inhibition of procyclic forms of Trypanosoma brucei brucei and phospholipases from T. congolense, T. b. brucei, T. vivax. The extract appears to be diallyl-disulfide (DAD) and may interfere with the parasites' synthesis of membrane lipids.

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