Growth dynamics and differential accumulation of picrosides and its precursor metabolites in callus cell lines of Picrorhiza kurroa with distinct anti-steatotic potential

Abstract

Picrorhiza kurroa is an industrially important Himalayan medicinal herb and is well known for its therapeutic potent picrosides compounds. The limited availability and medicinal usage of its rhizome commercially have initiated the searches for an alternative platform. Therefore, the present study developed a robust callus culture protocol from rhizome explant of P. kurroa to produce picrosides and its precursors metabolites. UPLC-PDA-ESI-Q-TOF-MS method was developed and validated for the analysis of 14 targeted metabolites in wild tissues and in-vitro calli of P. kurroa. Further, the anti-steatotic potential of crude extract was evaluated against the fatty acid-loaded Huh7 human hepatoma cell line. The rhizome callus showed appreciable antioxidant potential (IC50- 98.92 μg/mL) with 22.33% anti-denaturation activity. In rhizome callus, picrosides (PI, PII, PIII; 1.887 mg/g DW), precursors (2.118 mg/g DW), p-hydroxy acetophenone (0.316 mg/g DW), and 4-hydroxy acetophenone (0.032 mg/g DW) content were quantified. In anti-steatotic analysis, the crude extract of rhizome callus reduced the level of intracellular triglycerides, intracellular lipids, and reactive oxygen species in the fatty acid-loaded Huh7 cell line. Moreover, the callus extract significantly reduced the expression of fatty acid synthesis genes (SREBP-1c, FASN, and SCD1) and improved the transcription of fatty acid metabolism genes (CPT1 and CPT2).