Matured leaves of Stachytarpheta cayennensis were harvested from an abandoned, uncompleted building in Calabar, Nigeria in the month of February 2010. They were authenticated by comparison with the herbarium section of Botany Department (University of Calabar, Calabar) file voucher specimen. The leaves were air-dried in the laboratory at room temperature and then powdered. The powdered plant material (2kg) was homogenized with an electric blender in 4.2 litres of ethanol and water (4:1, v/v) at room temperature. The extract obtained was concentrated to dryness under reduced pressure with a yield of 46.99g (2.35%)

Freshly prepared extract was used to quantitatively analyse the bioactive constituents following standard methods described by Harbone (1993) and Trease and Evans (1983)

Thirty-two presumably healthy wistar rats of both sexes weighing between 160g and 200g were used in this study after approval by the Ethics Committee of the University of Calabar, Calabar-Nigeria. The animals were housed in well-ventilated cages in the animal house of the Department of Anatomy, University of Calabar, Calabar-Nigeria. They were fed with normal rat chow and given water freely using plastic containers with well fitted stainless steel nozzles. After a period of two weeks for acclimatization, they were randomly distributed into four groups A, B, C and D of eight rats each.

Streptozotocin (STZ) (Sigma Chemical Co., St. Louis, MO, USA) was reconstituted in normal saline (Atangwho et al., 2010). After an overnight fast, a single intraperitoneal injection of 65mg/kg body weight of STZ was given to twenty rats. After 72 hours of induction of diabetes fasting blood glucose was measured using One Touch Ultra Mini Glucometer (Lifescan Inc., USA) and only rats with blood glucose levels 12.7mmol/l (230mg/dl) and above were considered to be diabetic (Cetto et al., 2000). From the diabetic rats, eight rats each were randomly assigned to groups B and D

S. cayennensis extract was reconstituted using normal saline solution.

Group A: Normal control was given 0.4ml of normal saline solution once daily.

Group B: Diabetic control was given 0.4ml of normal saline solution once daily.

Group C: Non-diabetic, received 250mg/kgbw (0.4ml) of S. cayennensis extract once daily.

Group D: Diabetic received 250mg/kgbw (0.4ml) of S. cayennensis extract once daily

Experiment lasted for 21 days; thereafter the wistar rats after an overnight fast were anaesthetized using chloroform inhalation. The peritoneum was stripped open and the liver dissected out.

Tissue samples from the liver were fixed in 10% buffered neutral formalin, dehydrated in ascending grades of alcohol, cleared with xylene and embedded in paraffin wax. Thin paraffin sections at 5µm were stained using haematoxylin-eosin staining technique (Luna,1968)

Significance of differences was established using the unpaired Student’s t-test. Values at p<0.05 were considered significant

Proptosis was observed in the second week of study in groups C and D that received plant extract. Passage of loose stools and increased urination were observed from the first week of study. Apparent general malaise and high mortality of over 50% especially in the third week of study was observed in all the groups except the normal control (Group A). The study had to be shortened to 21 days because of this Cervical lymphadenopathy and epistaxis were observed in some rats in groups ( C and D) that received S. cayennensis leaf extract especially later in the second week of study.

The results of blood glucose levels in all the groups were shown in Table 1

Figure 1

Table 1: The effect of on wistar rat fasting blood glucose levels

Data represent mean ± SEM n=3 p<0.05

At the beginning of treatment, blood glucose levels in Groups B (Diabetic control) and D (diabetic, received 250mg/kgbw. of S. cayennensis¬¬¬¬¬¬¬¬ leaf extract) were significantly higher (p<0.05) than the blood glucose of the normal control. Blood glucose levels of Group A (normal control) remained within the same range throughout the study. In group B (Diabetic control) blood glucose continued to rise till the end of the experiment. In group C (Non-diabetic, received 250mg/kgbw of S. cayennensis leaf extract) blood glucose level continued to decrease till the termination of treatment but this decrease was not statistically different from the normal control and from the value at the beginning of the experiment. In group D (Diabetic, received 250mg/kgbwt of S. cayennensis leaf extract), there was a significant decrease in blood glucose level from the onset of treatment to the end of treatment. Though the blood glucose here was lower than the normal control, this variation is not significantly different from it.

Quantitative Phytochemical analysis, proximate and micronutrient composition of S. cayennensis aqueous ethanolic leaf extract.

Tables 2-5 show the percentage phytochemical and proximate composition and vitamin and mineral composition of S. cayennensis

Figure 2

Table 2 – Percentage phytochemical composition of

Data represent mean ± SEM n=3

Phytochemical analysis revealed the presence of alkaloids, flavonoids, saponins, tannins and phenols in S. cayennensis aqueous ethanolic leaf extract

Figure 3

Table 3 – Percentage proximate composition of aqueous ethanolic leaf extract

Data represent mean ± SEM n=3

Result revealed that S. cayennensis aqueous ethanolic extract is composed of carbohydrate (21.58±0.80%), protein (9.28±0.18%), dietary fibre (4.10±0.12%) and fat (3.66±0.02%)

Figure 4

Table 4 – Vitamin composition of aqueous ethanolic leaf extract

Data represent mean ± SEM n=3

Results revealed the presence of Vitamin A (4.14±0.03mg/100g), Vitamin C (56.91±1.03mg/100g), Thiamine (0.05±0.01mg/100g), Riboflavin (0.17±0.01mg/100g) and Niacin (0.41±0.02mg/100g)

Figure 5

Table 5 – Mineral composition of aqueous ethanolic leaf extract

Data represent mean ± SEM n=3

Results revealed the presence of Magnesium (60.00±2.40mg/100g), Calcium (90.85±2.31mg/100g), Potassium (225.47±1.18mg/100g), Sodium (11.07± 0.23mg/100g)

Phosphorus (68.03± 1.00mg/100g), Iron (0.65±0.01mg/100g), Copper (0.02±0.01mg/100g) and Selenium (0.01±0.00mg/100g)

Histopathological examination of liver

Histological examination of liver sections are shown in figures 1-4

Figure 6

Figure 1 – showing liver section of normal control (Group A)

Section reveals central vein (C), hepatocytes (H) arranged in cords radiating from the central vein. Also present are sinusoids (S).

Figure 7

Figure 2 – showing liver section of diabetic control (Group B)

Section reveals engorgement of the sinusoids (S), fewer hepatocytes

Figure 8

Figure 3 – showing liver section of non-diabetic wistar rats treated with 250mg/kgbw of aqueous ethanolic leaf extract of (Group C)

Section reveals mild sinusoidal engorgement and an apparently higher population of hepatocytes when compared with the diabetic control.

Figure 9

Figure 4 – showing liver section of diabetic wistar rats that received 250mg/kg body weight of aqueous ethanolic leaf extract

Section reveals a central vein, well-outlined hepatocytes and sinusoids. It resembles the section of the normal control.