Improved clonal propagation of Spilanthes acmella Murr. for production of scopoletin

Abstract

A reproducible protocol for clonal propagation of Spilanthes acmella has been established. Routinely, the cultures were established in spring (January-April) season because of the highest aseptic culture establishment and high frequency shoot proliferation. Incorporation of 5 lM N 6 -benzyladenine (BA) to Murashige and Skoog (MS) basal medium showed 100% bud-break and promoted multiple shoot proliferation in cultures. Interestingly, a higher concentration of BA (7-15 lM) promoted stunted shoots with pale leaves while a lower concentration (1-3 lM) resulted in shoots with long internodes and excessive adventitious root proliferation from all over their surface. For recurrent shoot multiplication, single node segments from in vitro-developed shoots were excised and cultured on MS ? BA (5 lM) medium where 20.3-fold shoot multiplication was achieved every 5 weeks. Finally, these shoots were successfully rooted on half-strength MS medium (major salts reduced to half-strength) with 50 g l -1 sucrose, with a frequency of 100%. Transplantation survival of micropropagated plants was 88.9%. Additionally, accumulation of scopoletin, a phytoalexin, was revealed for the first time in the uninfected leaves of Spilanthes. Further, the quantitative estimation by HPLC with a fluorescence detector showed that the amounts of scopoletin content (0.10 lg g -1 DW) in the leaves of micropropagated plants are comparable to those of field-grown mother plants. The study thus signifies the effectiveness of in vitro methodology for true-to-type plant regeneration of Spilanthes and their later utility for biosynthesis and constant production of scopoletin throughout the year.

Shoot regeneration and determination of iridoid levels in the medicinal plant Castilleja tenuiflora Benth.

“…IBA induced shoot formation from nodal segments of C. tenuiflora, but the proliferation rate was poor. The response of the nodal segments to this auxin may be because preexisting meristems developed into shoots (Singh and Chaturvedi 2010;Garcia et al 2011). In contrast, shoot proliferation and elongation were achieved by application of cytokinins.…”

Shoot regeneration from in vitro-derived leaf and root explants of Centaurea ultreiae

“…The use of this last cytokinin was also unsatisfactory in the formation of adventitious shoots from leaf explants of Crepis novoana (Corral et al 2010). In shoots of the Compositae Spilanthes acmella, the effect of kinetin on bud-break was significantly lower than BA, while 2iP was inhibitory (Singh and Chaturvedi 2010).…”

Enhanced Accumulation of Scopoletin in Cell Suspension Culture of Spilanthes acmella Murr. Using Precursor Feeding

“…The present study and previous reports suggest that the L-phenylalanine amino acid has effective role for production of secondary metabolites in cell culture of different plant species. Singh and Chaturvedi (2010) presented the first report on quantification of scopoletin from the leaves of in vitro and field-grown plants of S. acmella. Their study revealed that even the uninfected leaves of Spilanthes could accumulate the scopoletin.…”