In vivo studies of biochemical effects of root bark extract of Theobroma cacao (Linn.) on the anti-oxidative status of rats fed with high salt-diet

Abstract

In vitro antioxidant potential and membrane stabilizing effects of aqueous root-bark extract of Theobroma cacao, (L) and its fractions on erythrocyte of bovine (Bos indicus) exposed to heat and hypotonic induced lyses as well as its effects on oxidative enzyme status (GSH, GPx, MDA, catalase, SOD) of rats fed with high salt-diet were investigated. Rats were grouped into normal- treated, salt-treated and untreated; then placed on 4 % salt-diet and 1% salt-water for 21 days; after which they were orally exposed to 250 and 500 mg/kg body weight of flavonoid fraction. Phytochemical analysis of aqueous extract (AqE) revealed the presence of alkaloids, flavonoids, saponins, cardiac glycosides, tannins, steroids/phytosterols, xanthoproteins and triterpenes. The phenolic contents of AqE was 133.79 ± 0.00 mg and its fractions ranged between 0.82 ± 0.00 and 50.93 ± 0.00 mg TAE (tannic acid equivalent), while the flavonoid contents of AqE was 304.13 ± 0.01 mg and its fractions ranged between 8.36 ± 0.00 mg and 458.25 ± 0.01 mg RE/g (rutin equivalent). The fractions exhibited potent and appreciable DPPH-radical scavenging activity, ranged between 25.76 ± 0.39 % to 78.79 ± 1.12 %, ferric reducing antioxidant power between 11.92 ± 0.92 to 74.52 ± 2.37 μg AAE/ml (ascorbic acid equivalent) and compared favourably with the standard antioxidant compound. The fractions exhibited appreciable anti-inflammatory properties, with maximum membrane stability of 31.1 ± 4.14 % to 83.20 ± 2.05 %. Furthermore, the extract exhibited a biphasic response at all the concentrations tested. The activity of the extract compared favourably with that of acetaminophen (reference drug). The normal-treated, salt-treated and untreated groups of rats had increased (P<0.05) liver GSH level. The salt group, treated with 250 mg/kg body weight of extract had increased (P<0.05) liver GPx activity, while the normal-treated and untreated groups had decreased liver GPx activity. The normal group treated with 500 mg/kg body weight and salt group; treated with 250 mg/kg body weight of extract had decreased liver MDA level. There was no significant difference (P>0.05) between the activities of catalase and SOD, as well as the protein concentrations of the salt-treated and untreated animals. Slight decrease in body weights were observed in the salt-treated groups as against the slight increase in the untreated animals. Histologically, the extract protected the kidney tissues from renal dysfunction. The findings indicated that the root of cocoa possessed large spectrum of bioactive compounds that could be beneficial for the management of oxidative and inflammatory related conditions.