YIELD, CHEMICAL COMPOSITION AND ANTIOXIDANT PROPERTIES OF EXTRACTS AND ESSENTIAL OILS OF SAGE AND ROSEMARY DEPENDING ON SEASONAL VARIATIONS

Abstract

The aim of this research was to determine yield, chemical composition and antioxidant properties of extracts and essential oils of sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) leaves harvested during the months of June to September 2004. The maximum essential oil yields in the leaves were observed during July (3.24%) in sage and during August (1.35%) in rosemary. The maximum extract yields were found in July (15.57%) for sage and in June (30.48%) for rosemary. The sage oil was characterized by the presence of main components: camphore (20.73-26.07%), α-thujone (13.84-21.96), 1,8-cineole (13.94-20.40%), β-thujone (7.07-9.34%) and β-caryophyllene (2.28-9.19%). Fourteen compounds of rosemary essential oil were identified and the main components were found as camphore (14.77-31.12%), 1,8-cineole (7.70-26.18%), α-pinene (3.53-9.75%) and borneole (5.07-13.03%). Antiradical activities of sage and rosemary essential oils were found as IC50=2492.84-6645.43 μg ml and IC50=370.03-2812.50 μg ml, respectively. Antioxidant capacities were also 25.20-43.46 mg AAE g essential oil for sage and 18.53-37.95 mg AAE g essential oil for rosemary. Sage and rosemary essential oils distilled from the early season (June) harvested leaves had the highest antioxidant activity, expressed as low concentration providing 50% inhibition of antiradical activity and high levels antioxidant capacity. Total phenolic content was between 85.33-110.52 mg GAE g extract for sage and 94.29-104.44 mg GAE g extract for rosemary. It was the lowest in June and the highest July in both extracts. Both antiradical activities and antioxidant capacities changed significantly depending on the phase in the growing season. INTRODUCTION Antioxidants can minimize or prevent lipid oxidadation in food products (Shahidi and Wanasundara, 1992). Synthetic antioxidants such as butylated hydroxytoluene BHT, butylated hydroxyanisole BHA, propyl galate PG and tertiary butyl hydroquinone TBHQ. However, such synthetic antioxidants are not preferred due to toxicological concerns (Bracco et al., 1981). In the recent years, considerable attention has been devoted to herbs and spices with antioxidant properties. The use of herbs and spices as antioxidants in processed foods is a promising alternative to the use of synthetic antioxidants. A general recommendation to the consumer is to increase the intake of foods rich in antioxidant compounds (e.g. polyphenols, flavanoids, carotenoids) due to their well-known healthy effects. As a consequence, these evidences accelerated the search for antioxidants principles, which led to the identification of natural resources and isolation of active antioxidant molecules (Katalinic et al., 2005). Phenolic compounds are secondary metabolites that are derivatives of the pentose phosphate, shikimate, and phenylpropanoid pathways in plants, and exhibit a wide range of physiological properties, such as anti-allergenic, anti-artherogenic, anti-inflammatory, anti-microbial, antioxidant, anti-thrombotic, cardioprotective and vasodilatory effects (Balasundram et al., 2006). Many herbs and spices such as rosemary and sage belonging 383 Proc. I st IC on Culinary Herbs Eds.: K. Turgut et al. Acta Hort. 826, ISHS 2009 to the family Labiatae are an excellent source of phenolic compounds which have been reported to show good antioxidant activity (Schwartz and Ternes, 1992). The antioxidant activities of Labiatae family species could be mainly due to phenolic compounds, especially rosmarinic acid (Gerhart and Schroter, 1983; Capecka et al., 1997; Dorman et al., 2003; Erdemoglu et al., 2006). Rosemary and sage essential oils have also antioxidative properties. Antioxidant capacity of these essential oils is largely related with the phenolic compounds (Lu and Foo, 2001; Zheng and Wang, 2001; Stefanovits-Banyai et al., 2003; Durling et al., 2007). 1,8-cineole, camphore and borneole in rosemary and α-thujone, 1,8-cineole and camphore in sage oil are the primary essential oil components (Pitarevic et al., 1984; Boutekedjiret et al., 2003). The aim of the present work is to characterize the composition of the essential oils and extracts obtained from samples of leaves of sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) at different stages of the of plant growth and to determine their antiradical activities and antioxidant properties. MATERIALS AND METHODS Plant Material Sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) leaves harvested in approximately the middle of the month from June to December, 2004, at the Experimental Station of Suleyman Demirel University in Isparta, Turkey. Isolation of Essential Oil The plant leaves from Rosmarinus officinalis and Salvia officinalis were air-dried (200 g, each), mill powdered and water-distilled for 3h using Clevenger-type apparatus. The distilled oils dried over anhydrous sodium sulphate and, after filtration, stored at -20°C until tested and analyzed. Preparation of the Extract Dried and powdered herb material (15 g) were extracted with 100 ml mixture of methanol:acetone:water:acetic acid (55:40:4.5:0.5) for 2h by using an ultrasonicated water bath. The extracts were filtered and the solvent mixtures were concentrated by using both rotary evaporator (Rotavator, T<40C) under vacuum and lyophilizers (Virtis 2K, T=-60) to get crude extracts. The residues were stored in a desiccator until use. Analysis of Essential Oil Components Analyses of the essential oil components were performed on GC–MS/Quadropole detector, using a Shimadzu QP 5050 system, fitted with an FFAP (50 m×0.32 mm (i.d.), film thickness: 0.25 μm) capillary column. Detector and injector temperatures were set at 240°C. The temperature program for FFAP column was from 60°C (1 min) to 220°C at a rate of 5°C min and than held at 220°C for 35 min. Helium was used as a carrier gas at a flow rate of 14 psi. (Split 1:20) and injection volume of each sample was 5 μl. The identification of the components was based on the comparison of their mass spectra with those of Wiley and Nist, Tutore Libraries. The ionization energy was set at 70 eV. Analysis of Phenolic Constituents The procedure for quantization of the phenolic compounds has previously been described by (Capanio et al., 1999). The reversed phase-high performance liquid chromatography (RP-HPLC) was used. Detection and quantification was carried out with a SCL-10 Avp System controller, a SIL–10AD vp Autosampler, a LC-10AD vp pump, a DGU-14a degasser, a CTO-10 A vp column heater and a diode array detector set at 278 nm. The 250 x 4.6 mm i.d. C18 column used was filled with Agilent Eclipse XDB C-18 (250 x 4,6 mm), 5μ. The flow rate was 0.8 ml/min, injection volume was 10 μl and the column temperature was set at 30°C. Gradient elution of two solvents was used: Solvent