Chemical Composition and Antimicrobial Activities of Fruit Extracts of Ceratonia siliqua

Abstract

The aim of this study was to determine the chemical components and antimicrobial activities of water, thanol and hexane extracts of carob fruit. Gas chromatography-mass spectrometry (GC-MS) analysis of the fruit extracts revealed 21, 20, 28 compounds for water, ethanol and hexane extract respectively. The major compounds were alpha.-D-Glucofuranose 1,2:3,5-bis(benzeneboronate) (50.77%), 1H-Pyrazole, 4,5-dihydro-1,3-diphenyl (18.21%), 9,12,15-Octadecatrienoic acid, methyl ester, (Z,Z,Z) (13.96%) (water extract); Benzoic acid, 4-amino-, 4-acetoxy-2,2,6,6-tetramethyl-1-piperidinyl ester (23.12%), Benzenamine, N-dodecyl-N-methyl (18.37%), (ethanol extract); 9-Octadecenoic acid (Z)-, methyl ester (26.03), 9,12-Octadecadienoic acid (Z,Z)-, methyl ester (21.71%), Methyl stearate (16.82%), Hexadecanoic acid, methyl ester (12%) (Hexane extract). The antimicrobial activity of the fruit extracts with different concentrations (100, 80, 60, 40, 20, 10, 5 and 2.5 mg / ml) and selected antibiotic and antifungal were used against four strains of bacteria (two grampositive: Bacillus subtilis; Staphylococcus aureus and two gram-negative: Escherichia coli; Pseudomonas aeruginosa) and one type of fungus (Candida albicans) using disc diffusion method. Hexane and ethanol extracts with concentrations 80,60 mg/ml and 100, 80mg/ml respectively showed an inhibition zone 15,12mm and 15,13mm respectively against Escherichia coli which is comparable to that of tetracycline at 40mg/ml with an inhibition zone 13mm. Higher inhibition zone for hexane and ethanol extracts (18 and 17mm respectively) at concentration 100mg/ml was against Escherichia coli and Bacillus subtilis respectively. Ethanol and hexane extracts with concentration lower than 100mg/ml showed activity against Candida albicans with an inhibition zone 12 and 10mm compared to ultra griseo fulavin which has no activity at the mentioned concentrations but has antifungal activity at concentration 100mg/ml with an inhibition zone 16mm.