Tunisian Salvia officinalis essential oils: Variations regarding plant organs, harvest season and drying conditions

Salvia officinalis leaves
Type of data: 
Technical documentation
Personal communication outside INCREDIBLE events

This study presents an assessment of essential oils amounts and quality obtained from Tunisian Salvia officinalis and its variations regarding the plant organs, the harvest season and the plant's drying process conditions. Three drying processes were tested,  natural air drying, hot air convective drying at two temperature 40 and 60°C and microwave drying at 218 W. 


the extracted quantity and quality of Essential oils show important variations. these variations are explained by numerous factors such as the plants from which essential oils are obtained or the postharvest treatments that the plant is subjected to. Analysing these variations is important to optimize essential oil extraction.

Main results: 

The hydrodistillation using a Clevenger apparatus and a Gas Chromatography coupled to Mass Spectroscopy (GC-MS) were the methods applied to respectively extract and analyze the chemical composition of essential oils. The results showed that Salvia Officinalis leaves contained six times more essential oils than the stems. Summer harvesting period was more advantageous than winter and hot air convective drying at temperatures ranging between 40 and 60°C did not affect the essential oils yields compared to microwave drying which leads to important losses of essential oils. The main components found in Tunisian Salvia Officinalis essential oils were  (alpha) and  (Beta) -Thujone, 1,8-Cineole and Camphor.

Main practical recommendations: 

Getting more information on the effect of the intrinsic properties of the plant, the climatic changes and the post-harvest treatments on the amounts and quality of essential oils is interesting to industrials as well as pharmacists to get the best quality and the largest amounts of essential oils from plants at the lowest possible cost. Thus it is important to conduct experiments to optimize the extraction of essential oils from aromatic and medicinal plants.

Impacts and weaknesses: 

Impacts: Understanding the influence of factors such as the intrinsic properties of the plant, the climatic changes and the post-harvest treatments in order to optimize essential oils extraction is likely to be a powerful tool to reduce transport and manufacture costs and some social constraints associated with intensive manual weeding.
Weaknesses: Drying represents the most energy-consuming operation in aromatic and medicinal plant manufacture

Future developments: 

The current study succeeded to assess some variations in yields and quality of essential oils of Salvia Officinalis related to the plant organ used, the harvesting period, plant storing at ambient air conditions or dried by two different drying processes which are hot air convective drying and microwave drying. However, further investigations have to be considered regarding the biological activities of the essential oils obtained such as antioxidant, antiviral, antibacterial activities etc.


Monia Jebri, monia89@live.fr

 Ezzedine Saadaoui, saad_ezz@yahoo.fr 

Mehrez Romdhane, mehrez.romdhane1965@gmail.com

Further information

M. Jebri, H. Desmorieux, A. Maaloul, E. Saadaoui, M. Romdhane, Drying of Salvia officinalis L . by hot air and microwaves : dynamic desorption isotherms , drying kinetics and biochemical quality, Heat and Mass Transfer. (2018).

M. Jebri, J. Tarrazó, J. Bon, H. Desmorieux, M. Romdhane, Intensification of the convective drying process of Salvia officinalis : Modeling and optimization, Food Science and Technology International. 24 (2018) 382–393.

M. Jebri, Séchage des plantes aromatiques et médicinales et son influence sur l’extraction de leurs principes actifs: optimisation et modélisation, Ecole Nationale des Ingénieurs de Gabès, Université de Gabès, 2018.

Figure 1 credit: 

Monia Jebri 

Figure 2: 
SEM photo of salvia officinalis leaf surface
Figure 2 caption and credit: 

Monia Jebri