Callus initiation and regeneration of Curculigo orchioides Gaertn. and its untargeted metabolomic profiles using UHPLC-Q-Orbitrap HRMS compared to the parent plant.

Curculigo orchioides Gaertn. is a traditional medicinal plant widely used in Asia. However, it is often collected from the wild without replanting efforts. Additionally to its slow growth, its availability is further threatened by natural disasters and land-use shifting, putting its future supply at risk. This work aimed to obtain an efficient method for callus initiation and plant multiplication, investigate whether propagules produce secondary metabolites found in the mother plant. Combinations of plant growth regulators were used to initiate callus and/or shoots from leaf explants, and UHPLC-Q-Orbitrap HRMS identified metabolites. The explants cultured on MS medium supplemented with a combination of BAP (5 mg L^-1) and IBA (3 mg L^-1) initiated callus and regenerated plantlets. Through LC-HRMS analysis, several compounds with pharmacological effects were found in the in vitro propagules. In callus and plantlet leaves, 24 and 27 compounds were identified respectively, dominated by phenolics. Principal component analysis and hierarchical cluster discriminated the metabolites in the propagules and mother plant organs. The essential compounds, (1S,2R)-O-methylnyasicoside, curculigoside B, orcinol glucoside, 2,4-dichloro-5-methoxy-3-methylphenol were determined in callus at a higher concentration than in the mother plant. Conclusively, in vitro propagules of C. orchioides is a valuable alternative source of bioactive compounds.