Solubility of Flavonoids in Organic Solvents

Abstract

The solubility of quercetin, isoquercitrin, rutin, chrysin, naringenin, and hesperetin was quantified in acetonitrile, acetone, and tert-amyl alcohol. The solubility was strongly affected by both the nature of the solvent and the flavonoid structure. The highest solubility was obtained in acetonitrile for hesperetin (85 mmol·L-1) and naringenin (77 mmol·L-1) and in acetone (80 mmol·L-1) for quercetin. The lowest solubility value was obtained with rutin in acetonirile (0.50 mmol·L-1). The thermodynamic properties of flavonoids were also measured (melting point, enthalpy of fusion, and solid heat capacity) and predicted (liquid heat capacity, solid phase activity, and activity coefficient). Glycosylated flavonoids are characterized by a low melting point and a high enthalpy of fusion compared to the aglycon ones. Contrary to the data reported for other compounds, there is no clear correlation between the solubility of flavonoids and their thermodynamic properties. However, the conformational study showed that the flavonoids having a torsion angle OC2C1‘C6‘ of 40° are characterized by a high solubility.

In vitrobiological activity of secondary metabolites fromSeseli rigidumWaldst. et Kit. (Apiaceae)

“…However, it may be noticed that concentration of these substances depends on the polarity of the used solvent. High concentrations in acetone, ethyl acetate and methanolic extracts are the result of high solubility of these metabolites in the solvents, which is consistent with their chemical characteristics [4]. In previous studies, the greatest quantity of total phenolic compounds, including flavonoids, was achieved in acetone extract [5].…”

Hypoglycemic and anti–hyperglycemic study of Gynura procumbens leaf extracts

“…For instance, the intensity of astragalin and chlorogenic acid spots was higher in 75% ethanol extract than that in 0% extract. The amount of compounds present in the extracts depended on the solubility of compound in the extraction solvent, and since flavonoids have low solubility in water [21] , the increase in the water portion of the extraction solvents would reduce the amount of flavonoids extracted. Although chlorogenic acid was determined as a major chemical constituent in G. procumbens whose concentration depended on the polarity of extracting solvent system and extraction method, it was found that the total phenolic content was the highest in 50% ethanol extract, while chlorogenic acid content was the highest in 75% ethanol extract.…”

Diosmin Phytosomes: Development, Optimization and Physicochemical Characterization

“…5 Diosmin is considered to be a vascularprotecting agent used to help improving chronic venous insufficiency (CVI), 6 haemorrhoids, lymphedema, and varicose veins. 7 As a flavonoid, diosmin also exhibits anti inflammatory, 8 free-radical scavenging, 9 antidiabetic 10 and antimutagenic properties.…”