In vitro adventitious root culture of Withania somnifera L.: a strategy for enhanced secondary metabolite production with therapeutic antioxidant and anti-inflammatory potential

Abstract The adventitious root culture is an effective in vitro technique for producing valuable secondary metabolites. These cultures operate independently of the shoots and quickly provide a substantial raw material. This study is the first report aimed at reducing the cost of biomass production by encouraging adventitious root development and examining the potential of secondary metabolites produced from adventitious root cultures of Withania somnifera L. to kill cancer cells (Hep-G2) and reduce in vitro inflammation activity by testing their ability to prevent lipoxygenase and proteinase from performing their activities. IBA concentrations were tested to induce adventitious roots from W. somnifera L. plantlet leaves; the optimal IBA concentration was 1.0 mg/L. In addition, increasing the number of subcultures led to an increase in biomass to 5.84-fold in the fifth subculture. The macronutrient content, antioxidant tests, flavonoids, phenolic, and HPLC analysis were assessed. Anticancer and anti-inflammatory characteristics were evaluated. The results of total phenolics and total flavonoids were 27.42 ± 2.57 and 7.21 ± 0.14 mg/g Dw, respectively, and total antioxidant activities, including DPPH and ABTS, were 13.61 ± 2.21 and 18.31 ± 1.34 mg/g Dw, respectively. HPLC analysis revealed that catechin and gallic acid were the highest compounds, with concentrations of 419.26 and 249.73 µg/g, respectively, which correlated with strong anti-inflammatory and cytotoxic activities in vitro. Moreover, the IC50 for cytotoxicity against Hep-G2 was 100 µg/ml. In conclusion, the in vitro W. somnifera L. adventitious roots have shown promising results in the synthesis of secondary metabolites. Moreover, these adventitious roots have significant nutritional value, which increases antioxidant activity, in addition to their potential application as new natural secondary metabolites.