ANTIOXIDANT AND TOXICOLOGIC PROPERTIES OF METHANOL LEAF EXTRACT OF STEPHANIA DINKLAGEI IN WISTAR ALBINO RAT

ABSTRACT

Stephania dinklagei is used extensively in South East Nigeria for the traditional treatment of malaria and other associated ailments in form of decoction, in which unspecified quantities are usually consumed without due regards to toxicologic and other adverse effects. In this study, the phytochemicals were assessed as well as the effects of the antioxidant and toxicologic properties of methanol leaf extract of stephania dinklagei in Wistar albino rat. The rats were administered with graded doses of the extract twice daily for three weeks and the control administered with distilled water. Four rats each from the control and test groups were sacrificed every seven days and blood samples collected for analysis.  The percentage yield of stephania dinklagei methanol leaf extract was 5.5%. Preliminary phytochemical screening showed that the methanol leaf extract contained alkaloids, flavonoids, tannins, steroids, terpenoids, carotenoids, glycosides, anthocyanins and saponins. Anthraquinone was not detected. The quantitative phytochemical analysis showed that the extract contains alkaloids (29.70 + 0.15mg/g), flavonoids (25.30 + 0.10mg/g), steroids (69.70 + 0.10mg/g), saponins (13.57 + 0.21mg/g), tannins (64.21+ 0.21mg/g) cardiac glycosides (1.45 + 0.09mg/g), terpenoids (44.30 + 0.26mg/g), carotenoids (5.88 + 0.52mg/g) and anthocyanin (15.40 + 0.26mg/g). The vitamin content of the leaf extract was found to be vitamin A (44.8 + 0.42mg/100g), vitamin C (27.85 + 0.07mg/100g) and vitamin E (12.7 + 0.28mg/100g). The acute toxicity test of the leaf extract showed no toxicity up to 5000mg/kg body weight as observed over a period of 48 hrs for signs of acute toxicity. The extract was found to moderately scavenge the DPPH and superoxide anion radical in a dose dependent manner compared with their respective standards. The extract however, highly scavenged the hydroxyl radical when compared with the standard, α-tocopherol. There were no significant differences (p >0.05) in serum MDA level in all the groups in week I but significantly increased (p<0.05) in group 4 (week 2) when compared with that of their control. The serum SOD activity showed a significant decrrease (p<0.05) in all the groups of 1st, 2nd and 3rd weeks of the experiment when compared with that of their respective controls. Serum CAT also decreased significantly (p<0.05) in group 3 and 4 in week 3 compared with the control but no significant difference (p<0.05) was observed in all the groups in week 1 and 2. Serum ALP activity increased significantly (p<0.05) throughout the duration of the experiment when compared with that of their controls. Serum ALT level increased significantly (p<0.05) only in group 4 in the 1st, 2nd and 3rd weeks of the experiment. The same trend was observed with the AST level when compared with those of their controls. Creatinine showed a non-significant increase (p>0.05) in groups 2 and 3 but significantly decreased (p<0.05) in group 4 (week 1). There were also non-significant difference (p>0.05) in all the groups in week 2 when compared with that of their control but in week 3, there was non-significant increase (p>0.05) in groups 2 and 3 and a non-significant decrease in group 4. Urea level significantly increased (p<0.05) in all the groups throughout the duration of the experiment. Serum Na+ increased significantly (p<0.05) in week 1, 2 and 3 compared with those of their respective controls. Serum Cl- level showed non-significant difference (p>0.05) in week 1 and 2 but however, increased significantly (p<0.05) in week 3 compared with the control. Histological examination of the liver cells of the treated rats revealed widespread hepatocellular vacuolar degeneration with hypertrophy of kupffer cells in the periportal areas and moderate infiltration of mononuclear leucocytes into the periportal area as against that of their control. The histopathology result corroborates the results of the serum biochemical parameters. The kidney showed no significant changes in the treated groups compared with that of their control. These results suggest that Stephania dinklagei leaf extract had a significant in vitro antioxidant activity. However, long term consumption of the extract at the doses studied could be hepatotoxic but not nephrotoxic.