Genetic homogeneity assessment of in vitro-regenerated plantlets of Nyctanthes arbor-tristis L. and comparative evaluation of bioactive metabolites and antioxidant activity.

In vitro propagation of Nyactanthes arbor-tristis L. was achieved by culturing N-phenyl-N′-benzothiazol-6-yl-urea (PBU)-pretreated nodal explants in Murashige and Skoog (MS) medium without any phytohormones. Pretreatment of nodal explants in liquid MS medium with 100 μM N-phenyl-N′-benzothiazol-6-yl-urea for 4 d showed the highest shoot proliferation by producing maximum number of shoots (17.40 ± 1.02) per explant, with average shoot length of 5.96 ± 0.08 cm at the end of 8 wk. Effective rooting was accomplished by preincubating the cut-end of shoots with half-strength MS medium containing 6 μM indole-3-butyric acid for 1 wk, followed by implantation into half-strength MS medium; an average of 6.20 ± 0.049 roots per shoot were produced. Seventy-eight percent of the plantlets regenerated in vitro were successfully acclimatized and transferred to soil. These plantlets appeared to be morphologically similar to the donor plants. The genetic fidelity of these in vitro-regenerated plantlets was confirmed by start codon targeted polymorphism (SCoT) marker analysis, followed by comparative evaluations of the bioactive metabolites (ursolic acid, rengyolone, arbortristoside-A, and nyctanthoside), antioxidant-rich phytochemicals, and radical scavenging activities. This optimized in vitro propagation protocol should be an aid for the conservation of N. arbor-tristis germplasm, as well as cater to the needs of herbal industries for the production of therapeutic molecules. [ABSTRACT FROM AUTHOR]