Preliminary Investigation on Volatile Terpene Profiles from In Vitro Shoot Cultures of Thymus vulgaris L. Clones

Abstract

Thymus spp. serve as a natural source of essential oils, fresh and dried herbs, extensively used all around the world both in medicine and in cosmetic and alimentary industries. Essential oils of T. vulgaris have been reported to be among the top 10 essential oils. Objective of this preliminary investigation was to characterize different clones of T. vulgaris in vitro shoot cultures based on their volatile terpene composition. For this purpose, in vitro shoot cultures were established by transferring the excised shoot tips of in vitro germinated seedlings on semi-solid MS medium, supplemented with 1 mg/L kinetin and 0.3 mg/L gibberellic acid and subculturing in four-week intervals to the fresh medium of the same composition. Volatile terpene composition was determined by means of capillary gas chromatography. Variations in the terpene profiles were observed between the clones that were classified into two different chemotypes. Moreover, the use of the enantiomers of alpha-pinene was helpful to distinguish between the different clones. These data warrants further studies in order to compare the terpene composition of in vitro and in vivo plants and to establish the utility of micropropagation techniques to propagate selected chemotypes for industrial purposes.