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Aromatiuc herbs: contents and influence of harvest period

Lavandin, sage and rosemary are three of most important home and culinary plants. Antiradical activities and antioxidant capacities changed significantly depending on the phase in the growing season

In Turkey, Isparta province is known as valley of oil rose (Rosa damascena Mill.) and lavandin (Lavandula × intermedia Emeric ex Loisel. var. Super).
A Turkish scientific work have described the influence of the harvest time and drying temperature on the essential oil content and composition in lavandin which was harvested in four different dates (8, 15, 22 and 29 July 2005) and dried at four different temperature (30, 40, 50 and 60°C).
The oils were obtained from the dry inflorescences without stem. The two major components of the essential oil were linalool and linalyl acetate. Harvest time influenced the final content of essential oil. Essential oil content decreased from the first harvest (8.25%) to the last harvest (7.30%).
The highest linalool content (43.65%) was at the middle of the flowering season, and the highest linalyl acetate content (25.96%) was at the end of the flowering season.
Essential oil composition was also importantly influenced by the oven-drying temperature. 75.7% of essential oil was lost during oven drying at 60°C compared to drying at 30°C. There was decreasing in concentrations of linalool (from 42.91 to 34.13%), and increasing in concentrations of linalyl acetate (26.11 to 32.55%), when comparing essential oil composition from 30°C to 60°C treatments.

Another research show how yield, chemical composition and antioxidant properties of extracts and essential oils of sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) leaves could changing if 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%), -thujone (13.84-21.96), 1,8-cineole (13.94-20.40%), ß-thujone (7.07-9.34%) and ß-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%), -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-1 and IC50=370.03-2812.50 μg ml-1, respectively. Antioxidant capacities were also 25.20-43.46 mg AAE g-1 essential oil for sage and 18.53-37.95 mg AAE g-1 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-1 extract for sage and 94.29-104.44 mg GAE g-1 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.

Bibliografy

- Baydar, H. and Erbaş, S. 2009. EFFECTS OF HARVEST TIME AND DRYING ON ESSENTIAL OIL PROPERTIES IN LAVANDIN (LAVANDULA × INTERMEDIA EMERIC EX LOISEL.). Acta Hort. (ISHS) 826:377-382

- Baydar, H., Özkan, G., Erbaş, S. and Altındal, D. 2009. YIELD, CHEMICAL COMPOSITION AND ANTIOXIDANT PROPERTIES OF EXTRACTS AND ESSENTIAL OILS OF SAGE AND ROSEMARY DEPENDING ON SEASONAL VARIATIONS. Acta Hort. (ISHS) 826:383-390

by R. T.
01 june 2009, Technical Area > Science News

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