Induction and submerged cultivation of Valerianajatamansi adventitious root cultures for production of valerenic acids and its derivatives

Key message In vitro adventitious roots induced leaf of Valerianajatamansi showed improved metabolic profile and shorter cultivation cycle, thereby exhibiting potential as a sustainable alternative for extraction of industrially important phytoconstituents. In vitro adventitious roots were induced from leaves of Valerianajatamansi to assess their potential as a sustainable alternative to extract pharmaceutically important phytoconstituents. Among the different media used, a significantly (p <= 0.05) high root induction (90%) was achieved on Schenk and Hildebrandt (SH) medium fortified with 9.84 mu M indole-3-butyric acid (IBA). In addition, various process parameters i.e. IBA concentration, sucrose and medium strength were also optimized under submerged cultivation. The maximum fresh root biomass (144.09 +/- 11.36 g/L) with a high relative growth rate (2.01 +/- 0.04) and growth index (13.41) was achieved in half-strength SH medium having 2% sucrose and 4.92 mu M IBA. Further, a significantly high yield of total valerenic acid derivatives [1525.14 mu g/g dry weight (DW)] was recorded in adventitious roots as compared to donor plant parts. Individually, valerenic acid (506.27 mu g/g DW) was accumulated higher in plant rhizomes, while acetoxyvalerenic (534.91 mu g/g DW) and hydroxyl valerenic acid (919.57 mu g/g DW) in adventitious roots. Interestingly, hydroxy valerenic acid was unmeasurable in donor plant parts. The phenolic compounds were also found maximum in adventitious roots (451.85 mu g/g DW) with the dominance of pharmaceutically important kaempferol and rutin. A substantial increase in phytochemicals was evident at subsequent culture stages with shortened in vitro cultivation cycle (2 months) than field-grown plants (24 months). Moreover, adventitious roots also accumulated 0.059% essential oil with patchouli alcohol (24%) as a key constituent. Conclusively, an enriched metabolic profile and substantially shorter growth cycle under submerged cultivation undoubtedly demonstrated the potential of induced V. jatamansi adventitious roots as a feasible source of phytoconstituents.