Czech J. Food Sci. Vol. 28, 2010, No. 4: 275–279 Antimicrobial and Antioxidant Properties of Phenolic Acids Alkyl Esters Roman MERKL, Iveta HRÁDKOVÁ, Vladimír FILIP and Jan ŠmiDRKAL Department of Dairy and Fat Technology, 275 Vol. 28, 2010, No. 4: 275–279 Czech J. Food Sci. correlation between the molecular structure and antioxidant activity of phenolic substances has been 276 Czech J. Food Sci. Vol. 28, 2010, No. 4: 275–279 culture grew at the corresponding 277 Vol. 28, 2010, No. 4: 275–279 Czech J. Food Sci. Table 3. The minimum inhibitory concentrations (MIC) in mM of phenolic acid and their alkyl esters against tested microorganisms (A) Escherichia coli DMF 7503, (B) Bacillus cereus DMF 2001, (C) Listeria monocytogenes DMF 5776, (D) Fusarium culmorum DMF 0103, and (E) Saccharomyces cerevisiae DMF 1017 Methyl Ethyl Propyl Butyl Acid Methyl Ethyl Propyl Butyl Acid eesterster eesterster eesterster esterester Escherichia coli DMF 7503 (A) p-Hydroxybenzoic acid Protocatechuic acid Gentisic acid Vanillic acid Ferulic acid ND Caffeic acid Bacillus cereus DMF 2001 (B) p-Hydroxybenzoic acid Protocatechuic acid Gentisic acid Vanillic acid Ferulic acid ND Caffeic acid Listeria monocytogenes DMF 5776 (C) p-Hydroxybenzoic acid Protocatechuic acid Gentisic acid Vanillic acid Ferulic acid ND Caffeic acid Fusarium culmorum DMF 0103 (D) p-Hydroxybenzoic acid Protocatechuic acid Gentisic acid Vanillic acid Ferulic acid ND Caffeic acid Saccharomyces cerevisiae DMF 1017 (E) p-Hydroxybenzoic acid Protocatechuic acid Gentisic acid Vanillic acid Ferulic acid ND Caffeic acid MIC (mmol/l): >20.00 20.00 10.00 5.00 2.50 < 1.25 ; ND – not determined Possible explanation may reside in the higher Listeria) bacteria were observed. Moreover, the proportions of lipids and phospholipids contained sensitivity of Gram-positive bacteria was higher in the cell walls of the former. It can be seen most even in the case of phenolic acids and their methyl evidently in the case Fusarium. Significant dif- or ethyl esters. ferences between MIC values for Gram-negative Table 3 is arranged in the order from the lightest (Escherichia) and Gram-positive (Bacillus and shade (the highest amount of the tested substance) 278 Czech J. Food Sci. Vol. 28, 2010, No. 4: 275–279 to the darkest one (the lowest amount of tested dihydrocaffeic acids. Bioorganic & Medicinal Chem- substance). Propyl ester of ferulic acid was not istry, 9: 199–209. obtained in suitable purity, therefore its antioxi- Grunberger D., Banerjee R., Eisinger K., Oltz E.M., dant activity was not determined. Efros L., Caldwell. M., Estevez V., Nakanishi Antioxidant properties of the substances, ex- K. (1988): Preferential cytotoxicity on tumor cells by pressed as protective factors (PF), are shown in caffeic acid phenethyl ester isolated from propolis. Figure 1. It is obvious that some compounds show Experientia, 44: 230–232. pro-oxidation activity (ferullic acid, all deriva- Hrádková I., Šmidrkal J., Filip V., Merkl R., Kabrdo- tives of vanillic acid and some derivatives of p- vá E. (2009): Antioxidant stability of phenolic acids hydroxybenzoic acid). Gentisic acid exhibited and their esters. Czech Journal of Food Sciences, 27: approximately doubled PF, whereas its ester forms S41–S41. exhibited considerably low PF as a result of los- Masuda T., Yamada K., Akiyama J., Someya T., Oda- ing their antioxidant properties. Masuda et al. ka Y., Takeda Y., Tori M., Nakashima K., Maekawa (2008) described the antioxidant mechanisms T., Sone Y. 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(2002): Selective antiproliferative activity of fectively inhibit the growth of Bacillus cereus DMF caffeic acid phenethyl ester analogues on highly liver- 2001 and Saccharomyces cerevisiae DMF 1017. metastatic murine colon 26-L5 carcinoma cell line. Caffeic acid, its esters, and gentisic acid (only) show Bioorganic & Medicinal Chemistry, 10: 3351–3359. significant PFs (higher than 150%). Protocatechuic Psomiadou E., Tsimidou. M. (2002): Stability of virgin acid and its esters also possess antioxidant activity olive oil. 1. Autoxidation studies. Journal of Agricul- but their protection factor does not exceed 120%. tural and Food Chemistry, 50: 716–721. Silva F.A.M., Borges F., Guimaraes C., Lima J. L.F.C., Matos C., Reis S. (2000): Phenolic acids and de- Reference s rivatives: studies on the relationship among structure, radical scavenging activity, and physicochemical pa- Andrews J.M. (2001): Determination of minimum rameters. 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Accepted after corrections June 10, 2010 (2001): Mechanism of toxicity of esters of caffeic and Corresponding author: Ing. Roman Merkl, Vysoká škola chemicko-technologická v Praze. Fakulta potravinářské a biochemické technologie, Ústav technologie mléka a tuků, Technická 5, 160 28 Praha 6, Česká republika tel.: + 420 220 443 266, e-mail: [email protected] 279.