Micropropagation of Rehmannia glutinosa Libosch.: production of phenolics and flavonoids and evaluation of antioxidant activity

Abstract

Rehmannia glutinosa Libosch., a valuable medicinal plant, was successfully propagated in vitro using shoot tip explants. Shoot multiplication was performed in glass tubes and in a nutrient sprinkle bioreactor. A mixture of 0.1 mg L -1 indole-3-acetic acid (IAA) and 1.0 mg L -1 of 6-benzylaminopurine in Murashige and Skoog (MS) agar-solidified medium proved the best combination for multiple shoot induction, yielding 8.2 shoots per explant after 4 weeks of culture in glass tubes. The number of shoots increased to 21 per explant when the same combination of growth regulators was used in a nutrient sprinkle bioreactor. The shoots rooted with a frequency of 93 % after 6 weeks of culture on MS agar medium supplemented with IAA (0.1 mg L -1 ) before being acclimatized in the greenhouse. The antioxidant activities of methanolic extracts from the leaves and roots of the in vitro-regenerated plants of R. glutinosa cultivated in the greenhouse were evaluated using four in vitro assays: scavenging of free radicals (DPPH and ABTS), transition metal reduction and total antioxidant activity phosphomolybdenum test. In all cases, the methanolic extract from leaves demonstrated better antioxidant activity than those taken from roots. A strong correlation was found between total phenolic and flavonoid content, and the antioxidant capacity of the studied extracts.

Shoot organogenesis, molecular analysis and secondary metabolite production of micropropagated Rehmannia glutinosa Libosch.

“…seeds obtained from the Garden of Medicinal Plants of the Medical University in Wrocław (Poland) collected in 2006 were used in the study. The seeds were surface-sterilized and germinated as it was described earlier (Piątczak et al 2014). As explants, hypocotyls, root segments and cotyledons (3-5 mm long) excised from 30-day-old aseptically growing seedlings were used.…”

“…Six-week-old rooted shoots were removed from the culture vessels and transferred into pots as it was described earlier (Piątczak et al 2014). The survival rate was recorded after 10 weeks of growth in pots in a greenhouse.…”

“…A few studies describe the regeneration of R. glutinosa from leaf mesophil protoplasts (Xu and Davey 1983), leaves (Matsumoto et al 1989;Park et al 2009), root segments (Jeong et al 2002) and shoot tips (Shoyama et al 1983). In addition, one of our earlier studies describes the development of an in vitro propagation protocol for R. glutinosa using axillary buds (Piątczak et al 2014). There is currently a lack of information regarding the use of seedling explants for shoot regeneration of R. glutinosa.…”

Iridoid and phenylethanoid glycoside production and phenotypical changes in plants regenerated from hairy roots of Rehmannia glutinosa Libosch.

“…In the second, a mean number of seventeen HR-shoot tips (3-5 mm long) were placed into a 5 L sprinkle bioreactor containing liquid shoot multiplication medium (1 L). The bioreactor specifications have been described previously (Piątczak et al 2014). The circulation rate of the medium was 60 mL per each 40 s delivery, with 3.0 min breaks between each delivery.…”

“…A total of 30-45 shoots were used for each rooting medium variant: MS medium without plant growth regulators or supplemented with IAA or IBA (0.1 mg L -1 ). The rooted shoots were washed in tap water to remove agar from the roots and transferred into pots (Ø 10 cm) as described previously (Piątczak et al 2014). The experiments were repeated three times with 10-15 plants cultivated each time, giving a total of 40 plantlets transferred into pots.…”