Elicitation of Withania somnifera adventitious roots: in-vitro cultures for enhanced secondary metabolites synthesis

다국어 초록 (Multilingual Abstract)

The study examined Withania somnifera, an Ayurvedic medicinal evergreen shrub utilized for its potential applications to cure an array of ailments, particularly sexual dysfunction. Adventitious root (ARs) cultures were established from leaf explants and then stimulated with important elicitors such as melatonin (MT; 2.15, 4.3, 6.4, and 8.6 µM), methyl jasmonate (MeJa; 25–100 µM), and salicylic acid (SA; 100–300 µM). It was noted that the administration of these elicitors greatly affected the synthesis of withanolides and the buildup of bioactive compounds in suspension cultures of W. somnifera ARs. The results indicate that ARs grown on Murashige and Skoog (MS) medium with 6.4 µM Melatonin (MT) and 4.9 µM Indole Butyric Acid (IBA) unveiled the highest biomass accumulation among all other conditions tested. The growth kinetics of the root cultures were monitored on a weekly basis for a period of six weeks (42 days). The roots achieved a fresh mass of 13 g·L− 1 and a dry mass of 0.15 g·L− 1 on the 35th day when cultivated on MS liquid media containing MT plus IBA. Furthermore, results demonstrated that the roots treated with 100 µM and 25 µM doses of (MeJa) exhibited the highest Total Phenolic Content (TPC) of 35.8 mg g-1 DW, and 75.3% (DPPH) radical scavenging activity, respectively. Moreover, based on FT-IR and HPLC analyses of roots treated with 300 µmol of MeJa, we identified the existence of withanolides such as moupinamide and withaferin A, along with considerable amounts of phenolic compounds like Chlorogenic acid. This study concludes that MT inclusion to elicitors treated ARs of W. somnifera L. increases the root biomass in-vitro and also enhances the in-situ synthesis of important secondary metabolites. This strategy might be of future industrial application to produce withanolides on commercial scale sustainably.