In vitro mass clonal propagation of Dittrichia viscosa subsp. revoluta and analysis of its secondary metabolites

Abstract

SummaryIn vitro clonal propagation of native Portuguese Dittrichia viscosa subsp. revoluta was obtained from mature field-grown plants. High numbers of shoots (8–12 shoots per culture) were obtained for all clones and benzyladenine (BA) concentrations (0.44, 0.89 and 1.33 ゼM) tested. All clones developed numerous roots after auxin treatment, with the root length strongly dependent on auxin type (IAA, IBA, NAA). All plantlets were successfully acclimatized to ex vitro conditions, exhibiting normal development. The essential oils of D. viscosa were analysed by capillary GC and GC-MS using three types of plant material from the same clone: field-grown plant (FP), in vitro shoot-cultures (InV) and micropropagated plants (MP). The 24 identified components represented 39.9, 42.0 and 49.5% of the total oils in FP, InV and MP samples, respectively. The major constituents of the essential oils were 1,8-cineole (11.0, 5.1 and 5.1%), δ-cadinene (5.0, 7.0 and 6.6%); E-nerolidol (4.4, 9.7 and 11.9%); T-cadinol (7.1, 14.4 and 17.4%) and α-cadinol (6.7, 8.4 and 9.4%), for FP, InV and MP, respectively. Efficient separation of the flavonoids was achieved by RP-HPLC. Quercetin was the major component whose concentrations ranged from 0.3 mg per 100 mg FW, in FP, to 48.5 mg per 100 mg FW, in InV samples.