The plant Phyllanthus niruri was collected in the month of June, 2006 from the Imo State University Campus, Owerri, Nigeria. The plant was taxonomically identified and authenticated by Dr S.E. Okeke, Head, Department of Plant Science and Biotechnology, Imo State University, Owerri. The voucher samples were preserved in the university herbarium for future reference.

The entire plant of Phyllanthus niruri was sun dried for ten days before the final drying in an oven at 50°C for 24 hours. The dried plants were powdered in both manual grinder and electric grinder. Fifteen gramme of the P. niruri powder was soaked with 350ml of distilled water in a beaker and the mixture shaken on the laboratory bench for 24 hours before filtering. The filtrate was then evaporated by hot-air oven treatment at 40-50°C. Appropriate weights of the residue were prepared in distilled water to obtain the various concentration used for the experiments.

The chemical classes of constituent in the freshly prepared extract were detected using standard photochemical reagents and procedures as described by Trease and Evans (1983).

In general, test for the presence or absence of phytochemical compound using the above methods involve the addition of an appropriate chemical agent to the extract in a test tube. The mixture is then shaken vigorously or gently as the case may be. The presence or absence of saponins, flavonoids, tannins, alkaloids etc. was observed.

Male Wistar rats (200-300g) bred in the Animal House of College of Medicine and Health Sciences, Imo State University, Owerri were used in this study. They were housed in stainless steel cages and kept in a room where a 12-hour light/dark cycle was maintained. They were allowed free access to water and feed diet (product of Pfizer Nigeria Ltd ad libitum throughout the period of the experiment.

After one week of acclimatization, the rats were subjected to a 16 hour fast. Diabetes was induces with a single intraperitoneal injection of streptozotocin (STZ) at a dose of 65mg/kg body weight. The STZ was freshly dissolved in citrate buffer (0.01m, pH 4.5) (Ozsoy, Sacan, 2000). The injection volume was prepared to contain 1.0 ml/kg (Murali et al, 2002). After 5 days, blood glucose levels were measure and the animals with a concentration of more than 230 mg/dl were classified as diabetic (Cetto et al, 2000).

Twenty four male Wistar rats were used in this study. The rats were randomized and divided into four groups of six animals each.

Group 1: Normal, received normal saline solution (0.9% Nacl w/v, 5 ml/kg). Group 2: Diabetic, received STZ (65 mg/kg body weight) once Group 3. Diabetic, receive STZ (65 mg/kg body weight) once before receiving aqueous extract of Phyllanthus niruri (120 mg/kg body weight) Group 4: Diabetic received STZ (65 mg/kg body weight) once before receiving aqueous extract of Phyllanthus niruri (240 mg/kg body weight).

After 14 days of treatment, all the rats were decapitated after fasting for 16 hr. Blood was collected into tubes and allowed to clot and the serum collected for various hepatospecific markers estimations. The livers were dissected out and clear off blood.

The body weight and blood glucose levels were measured at the beginning and end of the experiment. Blood samples were obtained by tail vein puncture of both the normal and STZ-induced diabetic rats. Blood glucose levels were determined using a glucometer (Lifescan Johnson and Johnson Company, Milipitas, CA).

The acute toxicity of the extract was tested using 30 Wistar rats divided into 5 groups of 6 rats each, with each group receiving graded dose (250-1500 mg/kg body weight, intraperitoneally) of the aqueous extract of Phyllanthus niruri as described by Ghosh, (1984). After administration of the extract the rats were observed for toxic effects after 48 hours treatment. The toxicological effects were observed in terms of mortality expressed as LD₅₀. The number of animals dying during a period was noted. The LD₅₀ of the extract was estimated from the graph of percentage (%) mortality (converted to probit) against log-dose of the extract, probit 5 being 50% (Litch field, et al, 1959).

Serum total bilirubin level was estimated based on Van den Berg reaction (Malloy and Everlyn, 1937). Diazotised sulphonilic acid (0.5ml) reacts with bilirubin in diluted serum (0.2ml serum + 1.8ml distilled water) and forms purple coloured azobilirubin, which was measured at 540 nm. Activities of serum aspartate transaminase (AST) and Alanine transaminase (ALT) were assayed by the method of Reitman and Frankel (1957). 0.2 ml of serum with 1ml of substrate (asparatate and ?-ketoglutarate) for AST, alanine and ?-ketoglutarate for ALT, in phosphate buffer pH 7.4) was incubated for an hour in case of AST and 30 minutes for ALT. 1ml of DNPH solution was added to arrest the reaction and kept for 20 minutes in room temperature. After incubation 1ml of 0.4N NaOH was added and absorbance was read at 540 nm. Activities expressed as IU/L.

Based on the method of King and Armstrong (1934) alkaline phosphatase activities was assayed using disodium phenylphosphate as substrate. The colour developed was read at 680 nm after 10 min andf activities of ALP expressed as IU/L.

Statistical Analysis: Statistical evaluation of data was performed by using one way analysis of variance (ANOVA) followed by Duncan's multiple range test (DMRT) (Duncan, 1957).

The classes of chemical components of the aqueous extract of Phyllanthus niruri are shown in Table I. Alkaloids, flavonoids and saponins were found to be present while tannins, steroids, cyanogenic glycosides and cardiac glycosides were absent.

The results of blood glucose levels and body weight changes in normal, STZ-induced diabetic rats and P. niruri treated diabetic rats were shown in Table II. There was a significant (p< 0.01) increase in blood glucose levels in STZ-induced diabetic rats (Group II) when compared with normal rats. Administration of aqueous extract of P. niruri at a dose of 120 and 240 mg/kg body weight significantly (p<0.05) decreased blood glucose in STZ induced rats (Group III and IV). The results were found to be in a dose dependent manner.

The body weight changes in diabetic group was significantly decrease (p<0.05) when compared with the normal control which then returned to near normal in diabetic rats treated with aqueous extract of P. niruri at a dose of 120 and 240 mg/kg body weight

The changes in the mean value of serum bilirubin and serum hepatospecific enzyme markers in all the groups are shown in table III. There was no significant increase in the levels of total, conjugated and unconjugated bilirubin concentrations and AST, ALT and alkaline phosphatase activities in diabetic rats treated with aqueous extract of P. niruri at a dose of 120 and 240 mg/kg body weight (P > 0.05) when compared with both control and diabetic rats. While diabetic rats groups showed significant increase only in serum ALP activities (p <0.05) when compared with the control.