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M. DENT et al., Chem. Biochem. Eng. Q., 29 (3) 475-484 (2015) 475 Introduction Sage (Salvia officinalis L.) is a popular herb which is native to the Mediterranean region and cultivated worldwide. Sage is an important source of antioxidants used as preservatives and has wider implications for the dietary intake of natural antioxidants.1,2 This antioxidant effect has been attributed to the main phenolic components, caffeic acid dimer -rosmarinic acid 1 and flavonoids, being mostly present as flavones and their glycosides. Flavone glycosides are apparently common in sage, and most of them are flavones 7-glycosides represented by apigenin and luteolin 7-glucoside and their corresponding 3-and 7-glucuronides. 2 In the last few decades, research regarding the extraction of phenolic compounds found in plants have attracted special interest regarding their application in the food industry. Extraction is a very important step in the isolation, identification, and use of polyphenols. 3The conventional extraction methods, which have been employed for decades, require prolonged extraction times and relatively larger quantities of solvent.4,5 Therefore, various novel extraction techniques have been developed for the extraction of bioactive compounds from herbs, including ultrasound-assisted extraction, 6-8 microwave-assisted extraction, 9 supercritical fluid extraction. 10 Ultrasound-assisted extraction is an upcoming extraction technique that can offer high reproducibility in shorter time, higher yields of bioactive compounds, simplified manipulation, decreased temperature during processing, reduced solvent consumption, and lower energy input. [11][12][13] In our previous paper, 5 the influence of solvent polarity and composition, time and temperature of conventional extraction on mass fraction of polyphenols from sage were researched. The mixtures of ethanol and water are possibly the most suitable solvents for the extraction of sage due to different polarities of the active constituents, and acceptability of this solvent system for human consumption. 4,5 Albu et al. 3 and Sališova et al.14 have investigated the difference in the application of conventional extraction and ultrasonic-assisted extraction on the concentration of biologically active compounds in sage. They concluded that the content of biologically active compounds is approximately 60 % higher under the influence of ultrasound. Rosmarinic acid is the more active of these antioxidants, but it is relatively easily degraded in solvent and the rate of degradation is solvent-dependant.6 The ultrasonic-assisted extraction has been widely used for obtaining polyphenols from plants using ethanol, mixture of ethanol/wa- An innovative ultrasound-assisted extraction (UAE) is the rapid non-thermal extraction technique, which in comparison to conventional extraction (CE), offers high reproducibility in a short time with simplified manipulation, reduced solvent consumption and lower energy. Optimization of ultrasonic conditions was conducted for devices with nominal ou...

The objective of our research was to study the effects of growing area on polyphenolic composition and antioxidant capacity on sage leaves extracts (Salvia officinalis L.). The evaluation considered naturally growing sage, indigenous to the Mediterranean part of Croatia, specifically from Pag, Pirovac, Brač and Lošinj areas. The results indicate that sage is rich with polyphenols, which show evident antioxidant capacity. Variations of total phenolic contents and their composition, as well as antioxidant capacity between sage extracts grown at the various growing area, were significant (p ≤ 0.05). Rosmarinic acid (2460-3844 mg/100g) and lutolin-3-glucuronide (634-840 mg/100g) were found to be the main polyphenols in sage leaves studied. A significant correlation between total phenols, particularly the most representative phenolic compound rosmarinic acid and luteolin-3-glucuronide, was verified. Principal component analyses (PCA) indicates that the composition of polyphenols in sage has no significant deviation. Nevertheless, the content of polyphenols differed depending on the location direction of the growing area and environmental factors.

The effect of different hydrodistillation pretreatments, namely, reflux extraction, reflux extraction with the addition of cell wall-degrading enzymes, and ultrasound, on the yield and chemical composition of essential oils of sage, bay laurel, and rosemary was examined. All pretreatments improved essential oil yield compared to no-pretreatment control (40–64% yield increase), while the oil quality remained mostly unchanged (as shown by statistical analysis of GC-MS results). However, enzyme-assisted reflux extraction pretreatment did not significantly outperform reflux extraction (no-enzyme control), suggesting that the observed yield increase was mostly a consequence of reflux extraction and enzymatic activity had only a minute effect. Thus, we show that ultrasound and reflux extraction pretreatments are beneficial in the production of essential oils of selected Mediterranean plants, but the application of enzymes has to be carefully re-evaluated.