title: Antibacterial activity of naringin derivatives against pathogenic strains.
abstract: OBJECTIVE
  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.
  
  
  RESULTS
  The agar dilution technique and direct contact assaying were applied. NGE, prunin and NAR showed no antimicrobial activity at a concentration of 0.25 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 37°C and at a concentration of 0.25 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Instituto de Investigaciones para la Industria Química (INIQUI-CONICET), Universidad Nacional de Salta, Salta, Argentina. gceliz@unsa.edu.ar
authors.forename: G
authors.initials: G
authors.lastname: Céliz
authors.forename: M
authors.initials: M
authors.lastname: Daz
authors.forename: M C
authors.initials: MC
authors.lastname: Audisio
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002957:Citrus / Q000737:chemistry; D019453:Escherichia coli O157 / Q000187:drug effects*; D044950:Flavanones / Q000737:chemistry / Q000494:pharmacology*; D008089:Listeria monocytogenes / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010695:Phlorhizin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D044950:Flavanones; D010936:Plant Extracts; C506622:prunin; D010695:Phlorhizin; C005273:naringenin; C005274:naringin