Seasonal and Geographical Variation of Laurus nobilis L. Essential Oil from Tunisia~!2009-05-04~!2009-09-10~!2009-12-30~!

Abstract

Yield and composition of the essential oil obtained by hydrodistillation from leaves of laurel coming from ten different sites in Tunisia were determined. From each locality, leaves were harvested during four different vegetative stages (October, production of seeds; January, dormancy; April, flowering; July, vegetative activity) to look for some correlation between composition and vegetative stage. All 40 essential oil samples produced similar GC profiles containing a total of 71 peaks. 60 Compounds were identified. 1,8-cineole was, in all samples, the main constituent among different compounds such as methyl eugenol, -terpinyl acetate, sabinene and linalool. All essential oils considered were characterized by a clear predominance of oxygenated compounds chiefly monoterpenes then phenylporpanoids and sesquiterpenes. The concentration of this class generally decreases during the period October -July; the values are in the range 67.5% -86.1%. The yields of essential oil ranged between 0.65 and 2.2% by weight. With only one exception, the higher production of essential oil was obtained during the vegetative period. A seasonal variation in the yield and composition of essential oil was revealed, while geographical variability was not pronounced and no chemotypes were observed among the samples of laurel leaf oil examined.

Seasonal Variation in Volatile Oil, Polyphenol Content and Antioxidant Activity in Extract of Laurus nobilis Grown in Iran

“…Similar results are reported that a seasonal variation both in yield and composition of L. nobilis has been revealed [18]. By comparison with our research, all essential oils considered in a previous study have been characterized by a predominance of oxygenated compounds especially monoterpenes, phenylpropanoids and sesquiterpenes, respectively.…”

“…By comparison with our research, all essential oils considered in a previous study have been characterized by a predominance of oxygenated compounds especially monoterpenes, phenylpropanoids and sesquiterpenes, respectively. The concentration of this class (specially oxygenated phenylpropanoids) has been decreased during the period October-July [18]. Another study has been showed that the essential oil recovery increased in early June, reached a maximum in late July, and constantly decreased thereafter [16].…”

“…The antioxidant capacity was determined by a common used and highly accepted method. However, it was clearly noted that, there are a lot of variables affect on antioxidant activity in the literature [18]. Therefore, the numerous of antioxidant activity methods makes it necessary to use more than one method in such studies.…”

“…Generally, the yield and composition of the oil varies, depending upon the origin, the collection period, and the growth stage of the plant [17]. The study of the seasonal and geographical variation in yield and composition of leaf essential oil of L. nobilis collected from various areas in Tunisia showed that a seasonal variation both in yield and composition revealed, whereas geographical variability did not pronounce, and no chemotypes observed [18]. Seasonal variation in oil composition of L. nobilis grown in Portugal showed that during the period of highest essential oil yield (end of August), lower percentages of hydrocarbons and higher percentages of oxygenated compounds found [19].…”

Impact of geographic’s variation on the essential oil yield and chemical composition of three Eucalyptus species acclimated in Tunisia

“…Results of this study are in agreement with the findings of previous researches (Li et al, 1994;Li & Madden, 1995;Bignell et al, 1997;Della Porta et al, 1999;Tsiri et al, 2003;Marzouki et al, 2009), the chemical composition of the essential oils varied significantly within species and environmental conditions. Zrira et al (1994) The essential oils obtained from three Eucalyptus species acclimated in six arboreta were characterized.…”