Extraction and Biological Activity of Lignanoids from Magnolia officinalis Rehder & E.H.Wilson Residual Waste Biomass Using Deep Eutectic Solvents

Abstract

Lignanoids are an active ingredient exerting powerful antioxidant and anti-inflammatory effects in the treatment of many diseases. In order to improve the efficiency of the resource utilization of traditional Chinese medicine waste, Magnolia officinalis Rehder & E.H.Wilson residue (MOR) waste biomass was used as raw material in this study, and a series of deep eutectic solvents (ChUre, ChAce, ChPro, ChCit, ChOxa, ChMal, ChLac, ChLev, ChGly and ChEG) were selected to evaluate the extraction efficiency of lignanoids from MORs. The results showed that the best conditions for lignanoid extraction were a liquid-solid ratio of 40.50 mL/g, an HBD-HBA ratio of 2.06, a water percentage of 29.3%, an extract temperature of 337.65 K, and a time of 107 min. Under these conditions, the maximum lignanoid amount was 39.18 mg/g. In addition, the kinetics of the extraction process were investigated by mathematic modeling. In our antioxidant activity study, high antioxidant activity of the lignanoid extract was shown in scavenging four different types of free radicals (DPPH, ·OH, ABTS, and superoxide anions). At a concentration of 3 mg/mL, the total antioxidant capacity of the lignanoid extract was 1.795 U/mL, which was equal to 0.12 mg/mL of V_c solution. Furthermore, the antibacterial activity study found that the lignanoid extract exhibited good antibacterial effects against six tested pathogens. Among them, Staphylococcus aureus exerted the strongest antibacterial activity. Eventually, the correlation of the lignanoid extract with the biological activity and physicochemical properties of DESs is described using a heatmap, along with the evaluation of the in vitro hypoglycemic, in vitro hypolipidemic, immunomodulatory, and anti-inflammatory activity of the lignanoid extract. These findings can provide a theoretical foundation for the extraction of high-value components from waste biomass by deep eutectic solvents, as well as highlighting its specific significance in natural product development and utilization.

Keywords: biological activity; deep eutectic solvents; honokiol; magnolol; natural product extraction.

Figure 1

The molecular structure of (a) magnolol and (b) honokiol.

Figure 2

Single-factor investigation of the extraction process (a): liquid–solid ratio of 40 mL/g, water percentage of 30%, temperature of 338.15 K, and extraction time of 90 min; (b): DES composition molar ratio of 1:2, water percentage of 30%, temperature of 338.15 K, and extraction time of 90 min; (c): DES composition molar ratio of 1:2, liquid–solid ratio of 40 mL/g, temperature of 338.15 K, and extraction time of 90 min; (d): DES composition molar ratio of 1:2, liquid–solid ratio of 40 mL/g, water percentage of 30%, and extraction time of 90 min. (e): DES composition molar ratio of 1:2, liquid–solid ratio of 40 mL/g, water percentage of 30%, and temperature of 338.15 K.

Figure 3

The standardized Pareto chart of the main effects for (a) magnolol amount and (b) honokiol amount.

Figure 4

The response surface of the effect of independent variable interactions on magnolol amount (a): liquid–solid ratio and HBD-HBA ratio; (b): liquid–solid ratio and water percentage; (c): liquid–solid ratio and temperature; (d): liquid–solid ratio and time; (e): HBD-HBA ratio and water percentage; (f): HBD-HBA ratio and temperature; (g): HBD-HBA ratio and time; (h): water percentage and temperature; (i): water percentage and time; (j): temperature and time.

Figure 5

The response surface of the effect of independent variable interactions on honokiol amount (a): liquid–solid ratio and HBD-HBA ratio; (b): liquid–solid ratio and water percentage; (c): liquid–solid ratio and temperature; (d): liquid–solid ratio and time; (e): HBD-HBA ratio and water percentage; (f): HBD-HBA ratio and temperature; (g): HBD-HBA ratio and time; (h): water percentage and temperature; (i): water percentage and time; (j): temperature and time.

Figure 6

Kinetic fitted curves of (a) magnolol amount and (b) honokiol amount (liquid–solid ratio of 40 mL/g, HBD-HBA ratio of 2, water percentage of 30%, extract temperature of 338.15 K, and time of 90 min).

Figure 7

(a) Scavenging percentage and (b) total antioxidant and reducing capacity of lignanoid extract under different concentrations.

Figure 8

The (a) antibacterial activity, (b) α-glucosidase inhibition rate (IR), (c) α-amylase inhibition rate (IR), (d) sodium glycinate binding capacity (SGBC), (e) sodium taurocholate binding capacity (STBC), (f) cell viability, and (g–i) anti-inflammatory effect of the lignanoid extract.

Figure 9

The heatmap of magnolol and honokiol with the physicochemical properties of DESs and the biological activity of the lignanoid extract. * and ** denote a significant association at the p < 0.05 and p < 0.01 levels, respectively.

Figure 10

Chemical structures of (a) HBA (Choline chloride) and (b) HBDs (urea, acetic acid, propionic acid, citric acid, oxalic acid, malic acid, lactic acid, levulinic acid, glycerol, and ethylene glycol).