Phytochemical Compounds and Antioxidant Activity of Two Extracts of Wild and Domesticated Carob Leaves

Background and Objective: Carob tree (Ceratonia siliqua L.) is a perennial leguminous species and is known as a medicinal importance tree. This species exhibits a myriad of biological effects including antibacterial, antidiarrheal and antidiabetic. To this end, current study evaluates the difference between the phytochemical composition of the leaves of two accessions of "wild" and "domesticated" hermaphroditic carob trees. Materials and Methods: The comparison between two carob accessions "wild" and "domesticated" was done according to methanolic extraction by the Soxhlet and aqueous extraction by maceration. The polyphenols, flavonoids, tannins and their antioxidant activity were measured. The ANOVA test was used for the analysis of results. Results: The total polyphenols in aqueous extract are 6.19±0.25 mg equivalent gallic acid/g dry weight (EGA/g DW) and 4.23±0.2 mg EGA/g DW) in carob fresh leaves for wild and domesticated trees, respectively. The flavonoid content was higher in methanolic extract (3.17±0.64 mg quercetin equivalent/g DW) than in aqueous extract (1.06±0.19 mg EQ/g DW) for wild trees. Wild accession recorded the highest concentration of condensed tannins in the methanolic extract (6.4±0.3 mg catechin equivalents/g DW) while low levels were recorded in aqueous extract (0.51±0.27 mg EC/g DW). Conclusion: Such knowledge is expected to be the key to understanding the biochemical composition of two different leaves of C. siliqua accessions and its various commercial food products.