Application of Ionic Liquids in the Microwave-Assisted Extraction of Proanthocyanidins from Larix gmelini Bark

Abstract

Ionic liquid based, microwave-assisted extraction (ILMAE) was successfully applied to the extraction of proanthocyanidins from Larix gmelini bark. In this work, in order to evaluate the performance of ionic liquids in the microwave-assisted extraction process, a series of 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were evaluated for extraction yield, and 1-butyl-3-methylimidazolium bromide was selected as the optimal solvent. In addition, the ILMAE procedure for the proanthocyanidins was optimized and compared with other conventional extraction techniques. Under the optimized conditions, satisfactory extraction yield of the proanthocyanidins was obtained. Relative to other methods, the proposed approach provided higher extraction yield and lower energy consumption. The Larix gmelini bark samples before and after extraction were analyzed by Thermal gravimetric analysis, Fourier-transform infrared spectroscopy and characterized by scanning electron microscopy. The results showed that the ILMAE method is a simple and efficient technique for sample preparation.

Extraction of Proanthocyanidins and Anthocyanins from Grape Skin by Using Ionic Liquids

“…Similarly as previously observed by other authors (26,27), increasing the alkyl chain length from ethyl to butyl slightly enhanced the extraction effi ciency of proanthocyanidins, while on the contrary, further increase from butyl to decyl caused a drastic decrease. Moreover, this eff ect was also noticed in the extraction yield of other phenolic compounds from various plant matrices (21,22,35).…”

“…Structure of anions and cations, as well as the concentration of ILs can greatly aff ect the extraction yields of phenolic compounds (21)(22)(23)(25)(26)(27)(28)35). In order to evaluate IL performance in the extraction of main grape skin fl avonoids (proanthocyanidins and anthocyanins), eight diff erent imidazolium-based ILs varying in concentration (Table 1) were tested.…”

“…Previous studies have demonstrated promising applicability of imidazolium-based ILs in the extraction of diff erent phenolic compounds such as phenolic acids (gallic, ellagic, chlorogenic and caff eic acids) (21,22), stilbenes (trans-resveratrol) (21,23), fl avonols (quercetin, my ri cetin, kaempferol and rutin) (21,22,24,25) and proanthocyanidins (26,27) from various plant materials. In addition, physicochemical properties of ILs, which can be moderated and dictated by their structural characteristics of anion and cation, were also found to signifi cantly aff ect extraction yields of target analytes (21,22,27).…”

“…In addition, physicochemical properties of ILs, which can be moderated and dictated by their structural characteristics of anion and cation, were also found to signifi cantly aff ect extraction yields of target analytes (21,22,27). For instance, the solubility of phenols in ILs was shown to depend on the ability of phenols to form intra-and intermolecular bonds, as well as the polarity of ILs (28).…”

Application of ionic liquid-based ultrasonic-assisted extraction followed by rapid resolution LC-ESI/MS to chromone analysis from radix saposhnikoviae

“…Ionic liquids (ILs), also known as molten salts, are a new class of non-molecular ionic solvents with a melting point fixed at or below 100 °C [1] and have been proposed as greener alternatives to traditional organic solvents. ILs have a number of unique chemical and physical properties, such as negligible volatility and vapor pressure, good thermal stability, low flammability, chemical stability, environmental benignity, and good dissolution and extraction abilities [2][3][4][5].…”