Evaluation of genetic stability and analysis of phytomedicinal potential in micropropagated plants of Rumex nepalensis - A medicinally important source of pharmaceutical biomolecules

•High frequency regeneration protocol for medicinally important herb Rumex nepalensis using both DSO and ISO pathways.•Higher yields of secondary metabolites in vitro systems.•Clonal stability verified using molecular marker systems.

Rumex nepalensis is an important medicinal herb found in high altitude regions of India. It is a rich source of various secondary metabolites and has a widespread use in various herbal preparations. The regeneration efficacy of both direct shoot organogenesis (DSO) and indirect shoot organogenesis (ISO) was experimentally tested and the highest regeneration frequency for DSO and ISO pathways were 87.2% and 91.2% respectively. The best rooting frequency was recorded in half-strength MS medium supplemented with 2 mg/l NAA. The plantlets after acclimatization were phenotypically similar to that of the mother plant. The clonal stability of the regenerated plants from both DSO and ISO pathways were determined using Start Codon Targeted Polymorphism (SCoT) and Random amplified polymorphic DNA (RAPD) marker techniques. Although RAPD technique detected lesser degree of variability within the cloned plants (both DSO and ISO), SCoT marker could detect comparatively higher degree of genetic variability thereby proving its efficacy over the conventional molecular markers. Regeneration methodology, plant part and solvent system significantly influenced the levels of various secondary metabolites like phenols, flavonoids, alkaloids and tannins. Simultaneously, the antioxidant assays (DPPH and FRAP) detected the antioxidant activity varied tissue specifically and a significant higher value of antioxidant activity was observed within the ISO-derived plants. Higher multiplication rate coupled with enhanced clonal stability and secondary metabolite production recorded in the present report ensure the efficacy of the protocol designed for the micropropagation of this important medicinal herb species.