Elicitation and plant growth hormone-mediated adventitious root cultures for enhanced valepotriates accumulation in commercially important medicinal plant Valeriana jatamansi Jones

Adventitious root cultures of medicinally important Valeriana jatamansi Jones were induced in vitro and the growth kinetics of the root cultures were assessed upon supplementation of indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 1-naphthaleneacetic acid (NAA) and elicitors methyl jasmonate (MeJA) and salicylic acid (SA). NAA (2.0 mg/L) induced the highest biomass among the tested plant growth regulators (PGRs) and among the elicitor treatments, MeJA induced higher biomass of the root cultures compared to SA. Further, the root cultures obtained from each treatment were analyzed for their phytoconstituents and antioxidant potential. Total phenolic content (TPC), total flavonoid content (TFC), and antioxidant potential were found to be highest with the extracts of roots grown in liquid medium supplemented with NAA (2.0 mg/L). The elicitor MeJA induced higher biomass, but lesser phytoconstituents compared to NAA. SA, on the other hand, did not produce significant biomass. The GC-MS analysis revealed that NAA-treated roots accumulated 50 bioactive compounds similar to that of wild roots in which 48 compounds were detected including important valepotriates such as valeric anhydride, valeric acid, and derivatives. The SA elicitation resulted in the detection of 23 compounds including some valeric acid derivatives, and MeJA-treated cultures accumulated 21 compounds but did not aid in the production of valepotriates. Our results demonstrate that V. jatamansi root cultures can be effectively used for the large production of valepotriates by supplementing NAA.