Biological active compounds from Limonium insigne and alternative methods for its micropropagation

Abstract

Abstract The flavonoid composition of the Limonium insigne plants was analyzed by high-performance liquid chromatography, and mass spectroscopy (MS/MS and TOF). The results revealed the presence of luteolin-7-O-glucoside and apigenin-7-O-glucoside, as the major flavone glycosides, together with the aglycon flavanone naringenin. The maximum levels of these flavonoids in Limonium insigne plants were detected in inflorescence stems (148, 173 and 40 mg/100 g DW, respectively). Followed by leaves (129, 140 and 43 mg/100 g DW, respectively) and roots (29, 31 and 11 mg/100 g DW, respectively). The in vitro multiplication of Limonium insigne from axillary buds and by direct caulogenesis from leaf explants were evaluated. Of the hormonal treatments assayed (2 μM 6-benzylaminopurine; 5 μM kinetin; 2 μM 6-benzylaminopurine + 5 μM kinetin), the best response in the case of development from buds was obtained with 2 μM 6-benzylaminopurine + 5 μM kinetin, since a 57%, 82% and 196% increase in the number of leaves per explant with respect to the control was observed after 20, 40 and 60 days of culture, respectively. Leaf size was also greater, with a 64% increase in the longitudinal axis over the control values after 60 days. As regards caulogenesis, the Kinetin + ANA combination (5 μM + 0.5 μM) was the most successful for shoot formation (90%). For shoot rooting the best results were obtained with 10−6 M IBA. In the case of flavonoid content in micropropagated plants, it is very similar to the mother plants, being much lower in vitro plants. The possibility of using these two methods for the micropropagation of this rare and endangered plant speciesand as a source of flavonoids of pharmaceutical interest is discussed.