MATERIALS AND METHODS

Plant Material and Extraction
Capparis decidua stems were collected from Arkaweit area in Southern Khartoum and dried at room temperature. The plant was authenticated by the botanists in Medicinal and Aromatic Plants Research Institute and a poucher sample was deposited in the herbarium of the Institute.

Aqueous extract was prepared by infusion method and dried using freeze drier apparatus (Harborne, 1973). The coarse powdered part of the plant was also extracted successively with chloroform (60-80°C) and methanol (98%) using soxhlet extractor (Harborne, 1973). The solvent was evaporated under reduced pressure and the yields were calculated. The residue obtained was kept in dry clean bottles till used.

Phytochemical Screening
A general screening was carried out according to the method of Harborne (1973) to determine the chemical constituents of the plant material.

Experimental Design
Thirty five adult male Wister albino rats were used; the animals were grouped randomly into 7 groups of 5 rats each. Group I served as normal control and received only the vehicle liquid paraffin at a dose rate of 0.2 mL kg^-1/day 1/p for 10 days. Group II served as intoxicated control by given CCl₄-induced hepatotoxicity at a dose rate of 0.2 mL kg^-1 day 1/p in liquid paraffin (1:9) for 10 days. Group III served as hepatoprotective drug control when the rats were given CCl₄ at a dose rate of 0.2 mL kg^-1/day 1/p in liquid paraffin (1:9) for 10 days and at the same time received orally silymarin suspended in 5% Acacia mucilage at a dose of 100 mL/kg/day. Group IV, V, VI and VII rats were given CCl₄ at a dose rate of 0.2 mL kg^-1/day 1/p in liquid paraffin (1:9) for 10 days and simultaneous oral administration of either aqueous or methanolic extracts of C. decidua stems at a dose of 200 and 400 mg kg^-1.

Blood was collected by puncturing retroorbital plexus into dry clean bottles and allowed to clot for 30 min at room temperature. Serum was separated by centrifugation at 2500 rpm for 15 min and analyzed for various biochemical parameters. The biochemical parameters (alanine amino transeferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP) and total bilirubin (TBIL)) were analyzed using commercial kits (Plasmatic Laboratory. Products Ltd. Bridport DT6 5BU.U.K.) according to the manufacturers instructions.

At the end of the treatment, the animals were sacrificed by decapitation and post-mortem examination was performed. Small pieces of the livers were collected in 10% neutral buffered formal saline for histopathological study. Sections of 5-6 μ were cut and stained by haematoxyline and eosine.

Statistical Analysis
Statistical analysis of the results was performed using software Statistical Package for Social Sciences (SPSS). Mean values in serum parameters were compared using the student's t-test (Mendenhall, 1971).

RESULTS

Capparis decidua stems were extracted with different solvents (chloroform, methanol, water) and the yield percentages were higher in the methanolic extract (12.61%) followed by the aqueous extract (6.94%) and then the chloroform extract (1.45%).

The preliminary phytochemical analysis of the powdered material of plant revealed the presence of alkaloids, saponins, flavonoids, tannins, sterols, glycosides and cumarins. The plant was devoid of anthraquinone compounds.

There were no significant changes in the concentration of bilirubin and in AST, ALT and ALP levels in the control group I and standard drug group III.

In CCl₄ tested group II, the concentration of bilirubin and the activities of AST, ALT and ALP were significantly (p<0.001) increased when compared with the standard drug silymarin group (Table 1).

Simultaneous treatment with water extract of C. decidua stems to rats in group IV (200 mg kg^-1) and group V (400 mg kg^-1) significantly (p<0.001) reduced the activities of serum AST, ALT and ALP and concentration of bilirubin especially in group IV (200 mg kg^-1) compared with group II (CCl₄ group). There were no significant changes in these values when compared with group III (standard drug group).

Table 1:	Effect of C. decidua stems aqueous and methanolic extracts administered simultaneously with CCl4 on serum constituents levels on rats
Data are expressed as Mean±SD. The difference was found to be significant (°p<0.05, °°p<0.01, °°°p<0.001) when compared with CCl4-group and significant (*p<0.05, **p<0.01, ***p<0.001) when compared with standard drug group

The increase of the serum AST, ALT, ALP and bilirubin levels at day 5 and 10 days after CCl₄ administration was significantly (p<0.01-0.001) reduced by treatment with methanolic extract of C. decidua stems at 200 and 400 mg kg^-1 compared with group II (CCl₄ group) and (p<0.05-0.01) when compared with group III (standard drug).

DISCUSSION

The present study is an attempt to elucidate the likely hepatoprotective properties of C. decidua stems aqueous and methanolic extracts in carbon tetrachloride induced hepatotoxiciy model in rats.

Inadequacy of treatment with conventional drugs and possible hazards associated with their use prompted our search for better and safer hepatoprotectives of herbal origin. Ozbek et al. (2004) have proposed similar lines of investigation. In the present study, the choice of the plant has been based on the widely held folkloric belief that these plants possess effectivity against jaundice and they are component of many polyherbal formulations (El-Ghazali et al., 1987; El Kamali and El-Khalifa, 1999).

Determinations of serum levels of enzymes such as ALT and AST renders a reliable means of assessment of liver damage (Gupta et al., 2004).

The results using the model of CCl₄-induced hepatotoxicity in rats demonstrated that both extracts, aqueous and methanolic, from C. decidua stems reduced the levels of AST, ALT, ALP and bilirubin when given prior to CCl₄ intoxication. The decreased level indicates the stabilization of plasma membrane and protection of hepatocytes against CCl₄ damage (Manjunatha et al., 2008). This suggests a hepatoprotective activity endowed in this plant. Further supportive evidence is rendered by the observation that the necrotic lesions were also reduced in rats given both extracts.

The present results agree with previously reported data (Gupta et al., 2004; Singab et al., 2005; Manjunatha et al., 2008). Furthermore, the present study revealed the evidence of the existence of flavonoids, cyanogenic glycosides and triterpenes which are antioxidant and may be responsible for the hepatoprotective property of the plant as suggested by previous researchers (Al-Yahya, 1986; Evans, 2002; Satyanarayana et al., 2008; Gupta et al., 2004; Pattanayak and Priyashree, 2008). In addition, Yadav et al. (1997) reported that C. decidua was found to alter superoxide dismutase and catalase enzyme levels to reduce oxidative stress. Previous studies also showed that other species of the genus Capparis such as C. spinosa have potential protective activity against liver damage (Gadgoli and Mishra, 1995).

The present results have also shown appreciably high contents, in the plant, of minerals such as ferrous and vitamins such as vitamin C which may contribute to the extracts hepatoprotectivity as suggested by Duhan et al. (1992). The role of vitamin C in protecting liver damage may be attributed to the antioxidant properties of this vitamin in biological systems (Adams, 2001). Moreover, present results showed that the aqueous extract of C. decidua had higher activity than the methanolic extract, probably related to the more polar phytoconstituents.

Further investigation may have to be done to determine the exact phytoconstituent(s) responsible for the hepatoprotective effects of C. decidua.