Antibacterial activity of naringin derivatives against pathogenic strains

CÉLIZ, GUSTAVO; DAZ, MIRTA; AUDISIO, M. CARINA

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 111 p. 731 - 738

1364-5072

Aims: To study the antimicrobial activity of naringin (NAR), a flavonoid extracted from citrus industry waste, and NAR derivatives [naringenin (NGE), prunin and alkyl prunin esters] against pathogenic bacteria such as L. monocytogenes, E. coli O157:H7 and S. aureus. The relationship between the structure of the chemical compounds and their antagonistic effect was also analysed. Methods and Results: The agar dilution technique and direct contact assaying were applied. NGE, prunin and NAR showed no antimicrobial activity at a concentration of 0Æ25 mmol l)1 . Similarly, fatty acids with a chain length between C2 and C18 showed no antimicrobial activity at the same concentration. However, prunin-6¢¢-O-acyl esters presented high antibacterial activity, mainly against Gram-positive strains. This activity increased with increasing chain length (up to 10?12 carbon atoms). Alkyl prunin esters with 10?12 carbon atoms diminished viability of L. monocytogenes by about 3 log orders and S. aureus by 6 log orders after 2 h of contact at 37C and at a concentration of 0Æ25 mmol l)1 . The compounds examined were not effective against any of the Gram-negative strains assayed, even at the highest concentration. Conclusions: Addition of sugars to the aglycone did not enhance its antimicrobial activity. Attachment of a saturated aliphatic chain with 10?12 carbon atoms to the A ring of the flavonoid (or to sugars attached to this ring), seems to be the most promising modification. In conclusion, alkyl prunin esters with a chain length of C10?C12 have promising features as antimicrobial agents because of their high antilisterial and antistaphylococcal activity. Significance and Impact of the Study: This study shows that it is possible to obtain NAR derivatives with important antimicrobial activity, especially against Gram-positive pathogenic bacteria. It also provides guidelines on the structural modifications in similar molecules to enhance the antimicrobial activity.