Production and antioxidant capacity of tissue cultures from four Amaryllidaceae species

The aim of this study was (i) to produce tissue cultures capable of efficient plant regeneration from European naturally occurring protected and/or pharmaco-logically important Amaryllidaceae species and (ii) to test them for antioxidant activities in order to select tissue cultures that scavenge efficiently oxygen radicals. Bulb explants were collected from Galanthus woronowii, two Leucojum species, and Sternbergia lutea. Leucojum species were Hungarian isolates. Mostly alpha-naphthalene acetic acid (NAA) and benzyladenine (BA) were used as growth regulator combinations for the induction and maintenance of tissue cultures and further antioxidant activity studies. Galanthus woronowii and L. vernum cultures produced shoots or whole plants via micropropagation (callus stage was observed only sporadically and callus tissue did not contribute to regeneration), whereas L. aestivum and S. lutea produced efficiently whole plants or multiple shoots via embryogenic calli. Total phenolic content, % inhibition of ABTS radical (ABTS*) cation, and peroxidase activities on native polyacrylamide gels were studied and showed differences between cultures. No relationship could be detected between polyphenol content / radical scavenging capacities and H2O2 reducing enzyme activities. For G. woronowii, S. lutea, and a culture line of L. vernum, polyphenol content and ABTS* cation scavenging activities were high and for G. woronowii, comparable to organs of the native plants used as explant sources. Bulbs of native plants showed low radical scavenging activities in general. For L. vernum and L. aestivum tissue cultures grown in the presence of NAA as the sole growth regulator, ABTS* cation scavenging showed low values. Enzymatic antioxidant (pyrogallol peroxidase) activities were low for all cultures and organs of native plants. This study shows the species conservation value of these cultures and highlights the high antioxidant capacity of G. woronowii and S. lutea, attributed to the presence of non-enzymatic scavengers.