Accumulation of volatile constituents in agar and bioreactor shoot cultures of Verbena officinalis L.

Abstract

In vitro shoot cultures of common vervain ( Verbena officinalis L., Verbenaceae) were established and evaluated for essential oil content. The shoots were maintained as stationary microshoot culture, grown on Schenk–Hildebrandt medium supplemented with 9.84\xa0µM of 2-isopentenyladenine and 1.0\xa0µM of thidiazuron. The shoots were further adapted to grow in two temporary immersion bioreactors (RITA and Plantform), using Schenk–Hildebrandt medium supplemented with 4.92\xa0µM indole-3-butyric acid. The best growth, in terms of dry weight production, was recorded for agar culture (0.73\xa0g\xa0l −1 day −1 ), followed by 35\xa0days (day) Plantform (0.53\xa0g\xa0l −1 day −1 ), 35\xa0days RITA (0.42\xa0g\xa0l −1 day −1 ) and 56\xa0days Plantform culture (0.29\xa0g\xa0l −1 day −1 ). The volatile fractions were obtained by simultaneous hydrodistillation-extraction of the plant materials using Likens–Nickerson apparatus. Aerial parts of V. officinalis intact plant and 56 d Plantform culture had the highest essential oil content (8.1\xa0g\xa0kg −1 ) whereas the stationary agar culture excelled in essential oil productivity (5.0\xa0mg\xa0l −1 day −1 ). The volatile oils isolated from in vitro shoots contained 1-octen-3-ol, benzyl alcohol, phenethyl alcohol, coumaran and hexadecenoic acid as major constituents. 1-Octen-3-ol was the predominant (>\u200950%) constituent of 35\xa0day shoot cultures maintained in temporary immersion bioreactors whereas coumaran (19%) and hexadecanoid acid (21%) prevailed in stationary microshoot culture. The volatile fraction obtained from aerial parts of V. officinalis intact plant was composed mainly of hexadecanoic acid (>\u200920%), linalool (>\u20098%), anethole (>\u20095%) and carvone (>\u20093%). Microshoot cultures of Verbena officinalis , grown in temporary immersion bioreactors, were investigated in terms of essential oil content and composition of volatile fraction