Abstract

The present study aims at the quantification of phenolic compounds of Tunisian carob (Ceratonia siliqua L.) pods and the study of their in vitro and in vivo antioxidant activities in different extraction solvents. In this respect, we used 50 rats divided into five groups: Control and Carob-treated groups (100, 200, 600 and 1000 mg/kg, b.w.). Our results showed that the carob polar extracts are richer in total polyphenols, total flavonoids and condensed tannins than the nonpolar extracts with quantitative variation of phenolic compounds between seeds and pulp. In vitro, the determination of antioxidant capacity by 2,2'-azino-bis[3-ethylbenzthiazoline-6-sulphonic acid] (ABTS) method showed that carob extracts present high antioxidant potency in a solvent-compartment-dependent way compared to Trolox, an antioxidant reference molecule. In vivo, the subacute treatment within 7 days with aqueous extract of carob pods (AECP) decreased significantly and doses dependently the cerebral and myocardial lipid peroxidation as well as the level of hydrogen peroxide (H₂O₂) in kidney, liver and brain but not in heart. These data suggest that carob fruit presents an in vitro an in vivo antioxidant effects and might be proposed as a food additive to protect against oxidative stress damage.

Key words: Carob, phenolic compounds, antioxidant properties, rat.

Abbreviation

Abbreviations: ABTS, 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulphonic acid); AECP,aqueous extract of carob pods; CAT, catalase; GPx, glutathione peroxidase; MDA,malondialdehyde; ROS, reactive oxygen species; SOD, superoxide dismutase; TEAC,
trolox equivalent antioxidant capacity.