Immature carob pods extract and its fractions prevent lipid metabolism disorders and lipoprotein-rich plasma oxidation in mice: A phytochemical and pharmacological study.

ETHNOPHARMACOLOGICAL RELEVANCE: In Morocco carob fruits are used traditionally to treat hypercholesterolemia, diabetes and related diseases.

AIMS: This study was designed to evaluate the hypolipidemic activity of Ceratonia siliqua green pods extract and its fractions in Triton WR-1339 and high fat/cholesterol diet (HFCD) induced hyperlipidemia mice, as well as their ability to prevent lipoproteins oxidation in vitro.

MATERIALS AND METHODS: High performance liquid chromatography (HPLC) analysis was used to determine the phenolic composition of the immature carob pods extract (HWCE). Antioxidant activities were evaluated using the DPPH radical scavenging test as well as MDA measurement in oxidized lipoprotein rich plasma. Plasma lipids, glucose and biliary total cholesterol, as well as lipids level in liver and feces, were analyzed. The acute oral toxicity was performed in mice single dosed with the HWCE at 2000 and 5000 mg/kg body weight.

RESULTS: HPLC analysis shows that gallic acid is the main phenolic compound in the HWCE. The acute oral toxicity assessment revealed that the HWCE is not toxic (LD50 is greater than 5000 mg/kg body weight). In the acute hypolipidemic study, mice treated with the HWCE and its fractions exhibited a significant (P < 0.001) reduction in plasma total cholesterol (TC), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-C) levels. Importantly, immature carob aqueous extract was more effective in lowering mice hypercholesterolemia than its fractions. Indeed, mice fed the HFCD for 12 weeks showed a significant raise in plasma TC, TG and LDL-C, as well as in hepatic and fecal TC and TG levels. The HWCE at 100 and 200 mg/kg body weight significantly (P < 0.001) reversed the plasmatic levels of these lipid parameters, increased plasma HDL-C level, reduced hepatic lipids accumulation, but increased cholesterol level in the bile and fecal lipids excretion. The HWCE decreased also the atherogenic index, the LDL-C/HDL-C ratio and plasma glucose level after 12 weeks' experiment. On the other hand, the HWCE was more effective in preventing mice lipoprotein-rich plasma oxidation than its fractions, with a concentration-dependent manner.

CONCLUSION: C. siliqua green fruits extract could be effective in preventing atherosclerosis and related cardiovascular complications through the inhibition of lipoprotein oxidation and cholesterol clearance.