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Seasonal Variations of Phenolic Compounds and Biological Properties in Sage (Salvia officinalis L.)

The aim of this study was to investigate phenolic content and biological potential, as well as antioxidant and antibacterial activity of Dalmatian sage leaves collected during different vegetation periods. The separation and quantification of individual phenolics was done by HPLC-RP-PAD using internal standard method, while the content of total phenolic compounds, flavonoids, flavones and flavonols was detected spectrophotometrically. Five different assays were applied in antioxidant capacity evaluation of sage leaf extracts: FRAP, DPPH, ABTS, Briggs-Rauscher and β-carotene. Antimicrobial activity of sage extracts was tested against gram-positive (B. cereus and S. aureus) and gram-negative (Salmonella Infantis and E. coli) bacterial reference strains. All extracts were extremely rich in phenolics, and provided good antioxidant and antibacterial properties. The phenophase in which the leaves were collected had statistically significant impact on phenolic composition of sage extracts and consequently on their biological activity. May sage extract showed highest content of total flavonoids, best results for antioxidant properties using all methods and highest antimicrobial activity, thus being the best choice for further use in pharmaceutical and food industry.

sage; phenolic; antioxidants; antimicrobials; phenophase

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