Antioxidant and antimicrobial activities of Lavandula angustifolia Mill. field-grown and propagated in vitro

In the study, micropropagation of three varieties of Lavandula angustifolia was developed, and the appearance of trichomes, antioxidant activity of extracts and antimicrobial activity of essential oils isolated from plants growing in field conditions and in vitro cultures were compared. The study evaluated the number of shoots, and the height and weight of the plants grown on media with additions of BAP, KIN and 2iP. The greatest height was attained by the lavenders growing on MS medium with the addition of 1 mg dm-3 2iP – ‘Ellagance Purple’. The greatest number of shoots was developed by the ‘Ellagance Purple’ and ‘Munstead’ plants growing on the medium with 2 mg dm-3 BAP. The highest weight was attained by the plants growing on the medium with the highest concentration of BAP – 3 and 5 mg dm-3. Moreover, the present study determined the influence of media with the addition of different concentrations of IBA and media with a variable mineral composition  (½, ¼, and complete composition of MS medium) and with the addition of IBA or NAA for rooting. The majority of the media used had a positive influence on the development of the root system. The longest root system was observed in ‘Ellagance Purple’ growing on the medium composed of ¼ MS with 0.2 mg dm-3 NAA. All the examined oils exhibited activity towards S. aureus, S. epidermidis, P. aeruginosa, E. coli and C. albicans. The majority of the essential oils isolated from the plants propagated in vitro exhibited stronger antimicrobial activity than the field-grown plants. The plants propagated under in vitro conditions demonstrated considerably higher antioxidant activity as compared with the field-grown plants, which was determined using the DPPH, FRAP and ABTS assay.