Biochemical effects of root-bark extract of theobromacacao(Linn.) on lipid profiles and oxidative enzymes of rats fed with high salt -diet
ABSTRACT This study evaluated the in vitro antioxidant and anti-inflammatory potentials of aqueous root-bark extract of Theobroma cacao and its fractions in rats fed with high-saltdiet. This was with a view to explore its usefulness in the management of high-saltrelated ailments. Fresh root-bark of T. cacao (750 g) was extracted with 6.0 L of hot distilled water for 24 h and followed by evaporation under reduced pressure at 40℃ to obtain a residue (brown- flake) named aqueous extract (AqE). This was phytochemically screened and partitioned with solvents of increasing polarity to give hexane fraction (n-HF), ethyl acetate fraction (EAF), butanol fraction (n-BF) and aqueous fraction (AqF). The total phenolic and flavonoid contents of AqE and fractions were quantified. Thirty (30) albino rats were grouped into six (6) groups of 5 rats each. Group I served as control; groups II and III received salt-free diet and water with 250 and 500 mg/kg body weight(bwt) EAF. Group IV and V received 4 % (w/w) salt diet and 1 % (w/v) salt waterwith 250 and 500 mg/kg bwt EAF, while group VI received only 4% (w/w)salt diet and 1% (w/v)salt water constantly for 21 days.Biochemical changes as a result of exposure to salt-diet, salt water and EAF were investigated for 21 days. The effects of EAF on liver marker enzymes, lipid profiles as well as on the activities of oxidative enzymes were evaluated in the plasma and liver homogenates of rats. The histopathological evaluation of the kidney tissues was also carried out. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, cardiac glycosides, triterpenes, steroids/phytosterols, saponins and xanthoproteins. The phenolic content of AqE was 133.79 ± 0.02mgTAE/g (tannic acid equivalent) and its fractions ranged between 0.82 ± 0.07 and 50.93 ± 0.13mgTAE/g, while the flavonoid contents of AqE was 304.13 ± 0.13 mgRE/g (rutin equivalent) and the fractions ranged between 8.36 ± 0.11and 458.25 ± 0.16 mg RE/g. The fractions exhibited potent ferric reducing antioxidant power (FRAP). The fractions exhibited potent and appreciable DPPH radical scavenging activities and compared favourably with the standard(ascorbic acid). The fractions exhibited appreciable anti-inflammatory properties and compared favourably with the standard drug (Acetaminophen). There were significant differences (p < 0.05) in liver marker enzymes (ALT and AST) activities, total protein, total cholesterol, triacylglycerol, HDL-c, LDL-c and VLDL-c concentrations in the plasma and liver of treated animals. In addition, there were significant differences (p < 0.05) in the liver GSH, GPx andlipid peroxidation activities of the treated animals, although there were no significant differencesin the liver SOD and CAT activities of the treated animals, when compared with the control group. Histologically, 250 mg/kg bwt EAF protected the kidney tissues of the animals from renal dysfunction, caused by consumption of high-salt diet. The study concluded that the root-bark extract of T.cacao contained a broad spectrum of bioactive compounds that exhibited potent, significant and appreciable anti-inflammatory and antioxidant activities. It also reversed metabolic derangement associated with consumption of high salt-diet and water by experimental animals.