Optimization of Two Eco-Friendly Extractions of Black Medick (Medicago lupulina L.) Phenols and Their Antioxidant, Cosmeceutical, α-Glucosidase and α-Amylase Inhibitory Properties

Abstract

Medicago lupulina is an ancient edible plant from the Fabaceae family. In this work, two eco-friendly methods for extraction of bioactive phenolics from M. lupulina were developed using mixtures of water with two non-toxic, skin- and environmentally-friendly polyol solvents: glycerol and polypropylene glycol. Ultrasound-assisted extractions were optimized using a Box–Behnken design. The independent variables were the concentration of organic solvent in water (X1), extraction temperature (X2) and time (X3), while the response was phenolic content. The optimum conditions for extraction of polyphenols were (X1, X2, X3): (45%, 70 °C, 60 min) and (10%, 80 °C, 60 min) for glycerol and polypropylene glycol extraction, respectively. The extracts prepared at optimum conditions were rich in phenolic compounds, mainly derivatives of apigenin, kaempferol, luteolin, quercetin, caffeic and ferulic acid, as well as coumestrol. Their cosmeceutical and antidiabetic activity was tested. Both extracts demonstrated notable antioxidant, anti-lipoxygenase and anti-α-amylase activity. In addition to those activities, the glycerol extract efficiently inhibited protein coagulation, elastase and α-glucosidase activity. Glycerol present in the extract displayed enzyme-inhibiting activity in several assays and supported the action of the bioactive constituents. Thus, the optimized glycerol extract is a desirable candidate for direct incorporation in antidiabetic food supplements and cosmeceutical products.

Plants from Urban Parks as Valuable Cosmetic Ingredients: Green Extraction, Chemical Composition and Activity

“…On the other hand, the differences in the solubility of the flavonoid glycosides in DES80 and DES40 may be assigned to the different polarities of the two solvents, deeming them appropriate for dissolution of only specific derivatives. M. lupulina was previously found to be a rich source of apigenin, kaempferol, luteolin and quercetin derivatives [26]. Apigenin, quercetin and kaempferol derivatives were also previously found in K. arvensis [48] and L. croniculatus [49], as well as luteolin and apigenin derivatives in P. major [20].…”

“…The good activity of DES 80 may, at least to some degree, be explained by its high glycerol content. It has been previously noted that a high concentration of that polyol may effectively inhibit tyrosinase activity [26] The activities of DES40 (385.6 ± 47.9 µL solvent/mL) and γCD (558.8 ± 151.6 µL solvent/mL) were considerably less pronounced.…”

“…This indicates the important contribution that this solvent plays in the overall activity of the -DES80 extracts.The good activity of DES80 may be explained by the high glycerol concentrations that the solvent contains. Namely, it has been demonstrated that high glycerol concentration can negatively affect elastase activity[26]. DES40, with its IC50 being 2342.2 ± 156.1 μL solvent/mL, displayed only a negligible activity in this assay.…”

“…The precipitate on filter paper was washed with 60% ethanol and the filtrate was added to the flask contents to the volume. The solvents A and B were mixtures of water, methanol, and formic acid in the proportions 93:5:2 (v:v:v) and 3:95:2 (v:v:v) respectively [26]. They were applied in the following order: 0 min 20% B, 10 min 40% B, 35 min 50% B.…”

Glycerol and Natural Deep Eutectic Solvents Extraction for Preparation of Luteolin-Rich Jasione montana Extracts with Cosmeceutical Activity

“…All the extracts and the standards (0.2 mg/mL) were filtered through a 0.45 μm PTFE syringe filter (CHROMAFIL Xtra PTFE, Macherey-Nagel, Düren, Germany) before application. The solvents A and B were tertiary mixtures of water, methanol, and formic acid in the 93:5:2 ( v:v:v ) and 3:95:2 ( v:v:v ) ratio, respectively [ 22 ]. Solvents A and B were applied according to the following protocol: 0 min 20% B, 10 min 40% B, and 35 min 50% B.…”