NADES-based microwave-assisted single-step extraction process for extracting bioactive compounds from Amomum subulatum Roxb.: A sustainable approach.

A sustainable and energy-efficient method was developed to extract bioactive compounds from black cardamom (Amomum subulatum) using microwave-assisted extraction (MAE) with Natural Deep Eutectic Solvents (NADES). Six NADES composed of choline chloride, lactic acid, citric acid, glucose, and sucrose were prepared by heating and stirring. Lact:Suc and Lact:Gluc, showed the highest extraction efficiencies. Lact:Suc yielded a total phenolic content (TPC) of 48.99 ± 0.09 mg GAE/g, total flavonoid content (TFC) of 56.54 ± 1.98 mg QE/g, antioxidant activity of 98.39 ± 0.44%, and antioxidant capacity of 4588.92 ± 37.25 μmol AAE/g. Lact:Gluc achieved a TPC of 46.88 ± 0.31 mg GAE/g, TFC of 67.02 ± 0.88 mg QE/g, antioxidant activity of 96.64 ± 0.36%, and capacity of 4439.96 ± 30.42 μmol AAE/g. LC-ESI-MS profiling revealed solvent-specific selectivity: Lact:Suc favoured flavonoid glycosides, phenolic acids, and lignans, whereas Lact:Gluc was more effective for tyrosols and flavonoid aglycones. All NADES achieved a better extraction yield and compound specificity than ethanol. Greenness assessments (AGREEprep: 0.87; AGREE: 0.81) confirmed a strong alignment with green chemistry principles.