Extraction of Aloesin from Aloe vera Rind Using Alternative Green Solvents: Process Optimization and Biological Activity Assessment

Abstract

Aloesin is an aromatic chromone with increasing applications in the cosmetic and health food industries. To optimize its extraction from the Aloe vera leaf rind, the independent variables time (10–210 min), temperature (25–95 °C) and organic solvent composition (0–100%, w/w) were combined in a central composite design coupled with response surface methodology. The solvents consisted of binary mixtures of water with ethanol, propylene glycol, or glycerol. The aloesin levels quantified in each extract were used as response for optimization. The theoretical models were fitted to the experimental data, statistically validated, and used to obtain the optimal extraction conditions. Then, a dose–response analysis of the solid/liquid ratio (S/L) was performed under the optimal conditions determined for each alcohol–water system and revealed that a linear improvement in extraction efficiency can be achieved by increasing the S/L ratio by up to 40 g/L. This analysis also allowed to experimentally validate the predictive models. Furthermore, the aloesin-rich extracts revealed antioxidant activity through thiobarbituric acid reactive substances (TBARS) formation inhibition, antimicrobial effects against bacterial and fungal strains, and no toxicity for PLP2 cells. Overall, this study provided optimal extraction conditions for the recovery of aloesin from Aloe vera rind through an eco-friendly extraction process and highlighted its bioactive potential.

Optimized ultrasound-assisted extraction of phenolic compounds from Thymus comosus Heuff. ex Griseb. et Schenk (wild thyme) and their bioactive potential

“…Five complementary assays were used to evaluate the antioxidant potential of OpTC through different pathways: DPPH, TEAC (indicating radical scavenger activity), FRAP (ferric reducing antioxidant power), TBARS (evaluating lipid peroxidation through thiobarbituric acid reactive substances formation inhibition), and OxHLIA (oxidative haemolysis inhibition assay). For all assays, the detailed protocols are extensively described in our previous works [30] , [35] , [36] , [37] , [38] .…”

“…To quantify malondialdehyde (MDA)-TBA complexes, reaction tubes were centrifuged at 3000× g for 10 min, and the absorbance of the supernatant was read at 532 nm. Results were expressed as EC 50 values (μg/mL) [38] .…”

Phenolic profile, in vitro antimicrobial and in vivo diuretic effects of endemic wild thyme Thymus comosus Heuff ex. Griseb. (Lamiaceae) from Romania

“…Ampicillin and streptomycin (Panfarma, Belgrade, Serbia) were used as positive antibacterial controls (0.1-1 mg/ml). Commercial fungicides bifonazole and ketoconazole (0.1-1 mg/ml) (Srbolek, Belgrade, Serbia) were used as positive controls; all results were expressed as mg/mL (Añibarro-Ortega et al, 2021;García-Pérez et al, 2021).…”

Facile Synthesis of Antimicrobial Aloe Vera for Cosmetic Application

“…Previous studies have verified the possible spectrum wavelength numbers of each component consisting in the pure AV gel. Añibarro-Ortega et al (2021) have optimized the extraction of aloesin from AV using green solvents and the results have shown positive antimicrobial effects against bacterial and fungal strains. The findings of the components are listed in Table 4 as below.…”