Phenophase effects on sage (Salvia officinalis L.) yield and composition of essential oil

• S. officinalis essential oils constitute a source of bioactive compounds.
• The flowering phase was characterized by the highest essential oil production.
• The harvesting time affected significantly the essential oil yield and composition.
• PCA permitted to clearly discriminate the three studied phenological stages.

The main goal of the current study was to assess the phenological stage influences on yield and quality of essential oil of Salvia officinalis originating from two different regions and cultivated under the same experimental conditions. Results revealed the highest essential oil yielding (1.45, 1.49%) at the flowering phase. Analysis of the essential oils by GC/MS permitted the identification of sixty nine components and showed that the main components were 1,8-cineole (17.64–20.44%), α-thujone (15.66–25.23%), β-thujone (5.28–7.10%), camphor (6.00–24.36%) and viridiflorol (3.10–16.32%), but the percentages of these compounds varied depending on the phenological period. The flowering period was characterized by the highest production of 1,8-cineole (20.44, 19.28%). Camphor and viridiflorol percentages had a contrasting evolution in the course of the growth cycle, with the maximal levels detected respectively, at fruiting and vegetative phases. Additionally, substantial proportions of thujones (30.61, 27.96%) marked the fruiting stage. The accumulation of oxygenated monoterpene progressed during the phenological cycle of S. officinalis. Results from PCA revealed a clear discrimination between the three studied phenological stages. S. officinalis essential oil yields and volatile compounds percentages were significantly (p < 0.05) affected by the harvesting time.