Ultrasound-assisted extraction of flavonoids from Blumea balsamifera using deep eutectic solvents: optimization, characterization, and antioxidant evaluation

Figures

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  Fig. 1. Effect of different solvents on the extraction yield of total flavonoids from B. balsamifera. Different lowercase letters indicate significant differences (P < 0.05).

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  Fig. 2. Influence of various factors on the extraction yield of total flavonoids from B. balsamifera. (a) Effect of DES molar ratio; (b) Effect of water content; (c) Effect of ultrasonic power; (d) Effect of ultrasonic time; (e) Effect of ultrasonic temperature; (f) Effect of liquid–solid ratio.

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  Fig. 3. Interaction effects of factors on the extraction yield of total flavonoids from B. balsamifera. (a) Interaction between Factors A and B; (b) Interaction between Factors B and C; (c) Interaction between Factors A and C.

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  Fig. 4. ANN model performance and network parameters. (a) Training performance curve; (b) regression plots of ANN-predicted and experimental total flavonoid yields; (c) weight and bias matrices of the optimized 3–9–1 ANN topology.

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  Fig. 5. TFC obtained under five extraction modes. Different lowercase letters indicate significant differences (p < 0.05).

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  Fig. 6. FTIR and 1H NMR analyses of the ChCl-Gly DES (ChCl-Gly = 1:2). (a) FTIR spectra of ChCl-Gly DES, Gly, and ChCl. (b) 1H NMR spectra (DMSO‑d6) of ChCl-Gly DES, Gly, and ChCl.

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  Fig. 7. SEM of B. balsamifera powder (untreated) and residues after different extraction modes (×500). (a) Untreated powder before extraction; (b) residue after DES-UAE extraction; (c) residue after DES-HS extraction; (d) residue after EtOH-UAE extraction; (e) residue after EtOH-HS extraction; (f) residue after EtOH-REF extraction.

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  Fig. 8. Evaluation of antioxidant activity of B. balsamifera extracts from different solvents and VC. (a) DPPH radical scavenging ability of extracts from different solvents; (b) ABTS radical scavenging ability of extracts from different solvents; (c) Reducing power of extracts from different solvents; (d) Reducing power of VC.

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  Fig. 9. Pearson correlation analysis between total flavonoid yield and antioxidant activity of B. balsamifera extracts from different solvents.

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  Fig. 10. Cytotoxicity and cytoprotective effects of the DES-UAE extract in L02 hepatocytes. (a) Cytotoxicity at dilution factors of 10 × –100000 × with the matched DES blank (100 × ). (b) Protective effect against H2O2-induced injury at 100×, 200×, 400×, and 800 × with the matched DES blank (100 × ). Different lowercase letters indicate significant differences (P < 0.05).