Dry seeds of A. precatorius plant, were obtained from a local market in Ile-Ife (Osun state) and were authenticated by Mr. G. Ibhanesebhor of Ife-Herbarium, Department of Botany, Obafemi Awolowo University, Nigeria. A voucher specimen (No. 16282) was deposited at Ife-Herbarium. 1.0 kg of dried seeds of A. precatorius were ground into powder soaked in distilled water overnight and then filtered using muslin cloth and cotton wool in funnel. The filtrate was then concentrated in vacuo to give a residue (yield, 27.7% w/w).

Thirty-six albino mice of both sexes weighing between 20-24g and fifty-six Wister rats weighing between 150-190g were obtained from Animal House, Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria. They were kept in well ventilated polypopylene cages with steel grid floors and were given standard feed (produced by Ola Dokun, Ibadan, Nigeria) and water ad libitum. They were allowed to acclimatize with the environment at ambient temperature under natural day light/night conditions for two weeks before the start of the experiment.

Assay kits for the estimation of serum alanine aminotransferase, aspartate aminotransferase, albumin, cholesterol and bilirubin were purchased from Randox Laboratories Limited, U.K. All other chemicals were of analytical grade.

Acute toxicity studies were carried out using the method of Lorke, 1983. In the first phase, nine mice randomly divided into three groups of three mice each were given 10, 100 and 1000 mg extract/kg body weight p.o (via a cannula). The mice were observed for signs of adverse effects which include but not limited to paw-licking, salivation, stretching, rubbing of nose on the floor and wall of cage, change in body weight and death for 24 h and then weighed daily for 14 days. The surviving animals were sacrificed under chloroform anesthesia, autopsied and examined macroscopically for any pathological changes. The procedure was repeated using another set of nine mice, based on the results of the phase one study higher doses (1600, 2900 and 5000 mg extract/kg body weight p.o) was administered in the second phase. The number of deaths in each group within 24 h was recorded and the final LD₅₀ values were calculated as the geometric mean of the highest non-lethal dose (with no deaths) and the lowest lethal dose (where deaths occurred). The procedure for first phase above was repeated in mice using i.p and in the second phase lower doses (0.25, 0.50 and 1.0 mg extract/kg body weight i.p) were administered. This method was repeated using rats through oral route (lower doses 150, 200 and 500 mg extract/kg body weight p.o were administered in the second phase) and intraperitoneal route (lower doses 0.25, 0.50 and 1 mg extract/kg body weight i.p. were administered in the second phase).

Twenty Wister rats of either sex were divided into four groups of five rats each. Group one, which served as the control received distilled water (10 ml distilled water/kg body weight (i.p.), while rats in groups two, three and four were given 0.05, 0.10 and 0.20 mg extract/kg body weight (i.p.) respectively daily for 14 days. All the rats had food and water ad libitium for 14 days and they were observed daily for general symptoms of toxicity. The weight of feed and volume of water consumed by rats in each group were measured daily. Rats in all the groups were weighed twice every week during the period of treatment and on the last day of study. Doses of the extract administered were adjusted accordingly. On the 15 ^th day of the experiment, the rats that survived (one at a time) were euthanized in an air tight glass chamber saturated with chloroform, they were opened up surgically and blood samples were collected by cardiac puncture. One portion was collected into potassium + ethylenediaminetetraacetic acid (K + EDTA) bottles for estimation of Packed Cell Volume (PCV), haemoglobin concentration (Hb), red blood cell count (RBC), white blood cell count (WBC) and differential white blood cell count (lymphocyte, monocyte, eosinophil, basophil and neutrophil). Another portion was dispensed into plain vials, allowed to clot and centrifuged at 3500 rpm for 10 minutes. The sera were separated, stored at -4^oC and used for evaluation of biochemical assays.

Packed Cell Volume (PCV), haemoglobin concentration (Hb), red blood cell count (RBC), white blood cell count (WBC) and differential white blood cell count (lymphocyte, monocyte, eosinophil, basophil and neutrophil) were determined using the method of Barham and Trinder, 1972.

Rat serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) were determined by the enzymatic colorimetric methods of Reitman and Frankel, 1957 and Schmidt and Schmidt, 1963, alkaline phosphatase (ALP) was determined by the enzymatic colorimetric methods of Rec, 1972 and Englehardt, 1970, total bilirubin and direct bilirubin were determined by the enzymatic colorimetric methods Jendrassik, 1938 and Sherlock, 1951, total albumin was determined by the enzymatic colorimetric methods of Grant et al., 1987 and Doumaset al., 1971 and total cholesterol levels was determined by the enzymatic colorimetric methods of Abbel et al., 1952, Richmond, 1973, Roeschlau et al., 1974 and Trinder, 1969 ^{using commercially available kits (Randox, U.K),}

All quantitative data were expressed as the mean ± standard error of mean (SEM). Statistical analysis was carried out using one way analysis of variance (ANOVA) and significant difference between means was assessed by Bonferroni t-test at 95% level of significance using Primer (version 3.01).

At 0.10 and 0.20 mg/kg aqueous extract of A. precatorius seed elicited a significant (P < 0.05) decrease in feed intake in week 1 and week 2 when compared to the control (Figure 1).

Figure 1

Figure 1:

٭Significantly different from control at p < 0.05

Vertical bars: ± SEM; n = 5

At 0.05, 0.10 and 0.20 mg/kg, A. precatorius seed extract elicited a significant (P < 0.05) decrease in water intake in week 1 and week 2 when compared to the control (Figure 2).

Figure 2

Figure 2:

٭Significantly different from control at p < 0.05

Vertical bars: ± SEM; n = 5

At 0.20 mg/kg, the extract elicited no significant (P < 0.05) decrease in body weight in week 1 but there was a significant decrease in body weight of the rats in week 2 when compared to that of the control (Figure 3).

Figure 3

Figure 3:

٭Significantly different from control at p < 0.05

Vertical bars: ± SEM; n = 5

The group of rats treated with 0.05 mg/kg of extract exerted no significant (P < 0.05) change in haematological parameters when compared to that of the control. At 0.10 mg/kg there was a significant (P < 0.05) decrease in red blood cells and a significant increase in white blood cells when compared to that of the control while at 0.20 mg/kg there was a significant (P < 0.05) decrease in red blood cells, lymphocyte and eosinophil count, a significant increase in white blood cell when compared to that of the control (Table 1).

Figure 4

Table 1: Effect of Seed Extract on Haematological Parameters

٭Significantly different from control at p < 0.05

Values are mean ± SEM; n = 5

Effect of aqueous seed extract of A. precatorius on biochemical parameters

>A. precatorius seed extract at 0.05 mg/kg elicited a significant (P < 0.05) increase in serum alanine transaminase (ALT) and alkaline phosphatase (ALP). At 0.10 mg/kg and 0.20 mg/kg there was a significant increase in aspartate transaminase (AST), ALT and ALP and a significant decrease in albumin when compared to that of the control (Table 2).

Figure 5

Table 2: Effect of Seed Extract on Biochemical Parameters in Serum of Rats

٭Significantly different from control at p < 0.05

Values are mean ± SEM; n = 5