ANTIMICROBIAL ACTIVITY AND PHENOLIC COMPOSITION OF ASPHODELINE ANATOLICA E. TUZLACI LEAVES FROM TURKEY

Increasing prevalence of multi-drug resistant (MRD) strains worldwide with limited therapeutic options is a growing public health concern. Natural products have been shown to possess antimicrobial actions against multi-drug resistant strains (Lemos de Azevedo Maia et. al., Molecules, 16, 2011). The genus Asphodeline (Liliaceae) is represented in Turkey by 20 taxa, which are traditionally used for medicinal purpose in Anatolia region (Zengin & Aktumsek, Afr J Tradit Complement Altern Med, 11, 2014; Zengin et al., Food Chemistry, 135, 2012). Methanol, acetone and aqueous leaves extracts of Asphodeline anatolica E. Tuzlaci were examined for their antimicrobial activities against a panel of twenty Gram-positive and Gram-negative bacteria, including MDR strains, and yeasts. The broth microdilution method was used to determine the Minimal Inhibitory Concentration (MIC) and the Minimal Bactericidal Concentration (MBC) of the A. anatolica extracts. The HPLC-DAD-MS analysis was performed to determine the phenolic profile of extracts The acetone and methanol extracts showed most efficacy towards Gram-positive bacteria. Staphylococcus aureus was the most susceptible strains. Water extract demonstrated no activity against all microorganisms tested. Particularly, the acetone extract showed the higher bacteriostatic activity (MIC: 31,25-125,00 µg mL-1 against S. aureus ATCC 6538P and clinical isolates methicillin-resistant S. aureus (MRSA); 62,50-125,00 µg mL-1 against L. monocytogenes ATCC 13932 and L. monocytogenes food isolates; 500,00 µg mL-1 against Pseudomons aeruginosa ATCC 9027) than methanol extract (MIC: 125,00-500,00 µg mL-1 S. aureus ATCC 6538P and clinical isolates MRSA; 250,00 µg mL-1 against Staphylococcus epidermidis). The HPLC-DAD-MS analysis revealed the presence of phenolic compounds; within the flavonoids diosmin and cirsimaritin were detected as the main constituents in acetone extract, while rutin was the main constituent in methanol extract. The results obtained demonstrate a direct relationship between the phenolic content of the extracts and the antimicrobial effect.