Fenfang Li

Extraction and purification of anthraquinones derivatives from Aloe vera L. using alcohol/salt aqueous two-phase system

An alcohol/salt aqueous two-phase system (ATPS) composed of 1-propanol and (NH4)2SO4 was employed to purify anthraquinones (AQs) extracted from Aloe vera L. The main influencing system parameters such as type of alcohol, type and concentration of salt, temperature and pH were investigated in detail. Under the optimal extraction conditions, AQs can be extracted into alcohol-rich phase with high extraction efficiency, meanwhile majority polysaccharides, proteins, mineral substances and other impurities were extracted into salt-rich phase. Partitioning of AQs is dependent on hydrophobic interaction, hydrogen bond interaction, and salting-out effect in ATPS. Temperature also played a great role in the partitioning. After ATPS extraction, alcohol can be recycled by evaporation; moreover, salt can be recycled by dilution crystallization method. Compared with other liquid–liquid extractions, this alcohol/salt system is much simpler, lower in cost with easier recovery of phase-forming components, which has the potential scale-up in down-processing of active ingredients in plant.

Separation and Purification of Aloe Anthraquinones Using PEG/Salt Aqueous Two-Phase System

The anthraquinones were extracted from Curacao aloe leaves. Aqueous two-phase system (ATPS) of polyethylene glycol (PEG)/salt, coupled with spectrophotometry and high performance liquid chromatography (HPLC) were employed for the first time as an attractive alternative for the downstream processing of aloe anthraquinones, mainly for the removal of the impurities without additional steps. The influence factors such as molecular mass and concentration of PEG, type, and concentration of neutral salt, temperature, and pH on the phase partition behavior of ATPS had been studied. Under the optimal condition, the highest extraction yield 90.54% was obtained in PEG phase using PEG-6000/(NH4)2SO4 system to a mass ratio of 2:1 at 40°C, pH 3.0 with 0.6 g sodium chloride added. The reverse extraction of anthraquinones from the PEG phase was achieved with a recovery of 70.15% by adjusting the pH. Meanwhile, the PEG could be recycled. The major components in aloe anthraquinones of aloe-emodin and chrysophanol were analyzed by HPLC before and after ATPS extraction process. Compared with conventional purification methods, this technique can be completed in one operation; besides it is low-cost and environmentally friendly.

Applications of choline amino acid ionic liquid in extraction and separation of flavonoids and pectin from ponkan peels

ABSTRACT Choline leucine ionic liquid solution was chosen to simultaneously extract flavonoids and pectin from ponkan peels, which were subsequently isolated by the corresponding K3PO4-based aqueous biphasic systems (ABS). Under optimized conditions of 54% solution for 100 min extraction at liquid–solid ratio 17, the predicted yields of flavonoids and pectin achieved 1.33% and 13.42%, respectively, the flavonoids determined directly after extraction and the pectin after ABS purification, with the two corresponding measured yields of 1.26% ± 0.04% and 12.85% ± 0.51%. Under optimal extraction, crude flavonoids contained maximal total flavonoid content of about 20% ± 1% after purification of the ABS involving 25% K3PO4 and dilution precipitation. What was directly isolated from K3PO4-rich phase was presumed to be a modified pectin.