Phytochemical constituents and biological activities of Ceratonia siliqua L. leaves grown in western Algeria

Abstract

Ceratonia siliqua L. belongs to the Leguminosae family. It is native to the Middle East and has spread throughout the Mediterranean Basin, western America, South Africa and southern Australia. Phytochemical profile and biological activities of this plant leaves were evaluated in the present work. Findings show that the leaves contain useful nutrients and interesting amount of phenolics, flavonoids and condensed tannins. Antioxidant activities were determined using DPPH and FRAP. An IC50 of 7 and 30 μg/mL was obtained by DPPH test for organic and aqueous extracts, respectively. Subsequently, the organic extract of carob leaf polyphenols (CLP) was assessed for biological activities. This extract exhibited considerable anti-α-amylase activity with IC50 of 0.09 mg/mL. Indeed, an advantageously low hemolytic activity was noted towards human erythrocytes. Further, the antimicrobial activity was evaluated using disc diffusion method against Gram positive bacteria namely S. aureus, B. cereus, B. subtilis and M. luteus and Gram negative bacteria namely P. aerugenosa, E. coli and K. pneumoniae. Also the fungus C. albicans was tested. Interestingly, S. aureus expressed the greatest sensitivity to treatment with minimum inhibitory concentrations (MIC) of 2.5 μg/mL. Results obtained highlight the panoply of biological activities of C. siliqua leaves as antioxidant, hypoglycemic, antimicrobial agent with low toxicity.