Characterization of an Italian biotype of clary sage (Salvia sclarea L.) grown in a semi-arid Mediterranean environment

An Italian spontaneous biotype of clary sage (Salvia sclarea L.) was evaluated for its suitability to be cultivated in a semi-arid area and for the influence of these growth conditions on the essential oil composition. Seeds gathered from a spontaneous biotype were sown directly in the field, using a seeding density calculated to achieve a plant population of 7 plants/m2. Essential oils from the inflorescences and leaves of plants harvested at full flowering and early seed ripeness stages were obtained by steam distillation and characterized by GC and GC-MS. The plants showed a good tolerance to the semi-arid growth conditions, yielding more than 700 flowers/plant and about 21 g seeds/plant. Relevant qualitative and quantitative differences were detected between the essential oils from the inflorescences and leaves, the former being characterized by a high content of linalool (26-29%) and linalyl acetate (35-53%) and the latter only by sesquiterpenes, with germacrene D as the main compound (68-69%). Inflorescences at full flowering stage were richer in linalool, α-terpineol and germacrene D, showing a lower content in linalyl acetate in comparison with those collected at early seed ripeness. The development stage did not influence the oil composition of leaves.