Separation of high-purity syringol and acetosyringone from rice straw-derived bio-oil by combining the basification-acidification process and column chromatography

The ionic liquids upon perchlorate to promote the C-C/C-O bonds cleavage in alkali lignin under photothermal synergism

Transforming lignin into aromatic monomers is critically attractive to develop green and sustainable energy supplies. However, the usage of the additional catalysts like metal or base/acid is commonly limited by the caused repolymerized and environmental issues. The key step is to mediate electron transfer in lignin to trigger lignin C-C/C-O bonds cleavage without the catalysts mentioned above. Here, we report that the ionic liquids [BMim][ClO4] was found to trigger lignin electron transfer to cleave the C-C/C-O bonds for aromatic monomers without any additional catalyst. The proton transfer from [BMim]+ to [ClO4]- could polarize the anion and decrease its structure stability, upon which the active hydroxyl radical generated and induced lignin C-C/C-O bonds fragmentation via free radical-mediated routes with the assistance of photothermal synergism. About 4.4 wt% yields of aromatic monomers, mainly composed of vanillin and acetosyringone, are afforded in [BMim][ClO4] under UV-light irradiation in the air at 80 °C. This work opens the way to produce value-added aromatic monomers from lignin using an eco-friendly, energy-efficient, and simple route that may contribute to the sustainable utilization of renewable natural resources.

Syringol isolated from Eleusine coracana (L.) Gaertn bran suppresses inflammatory response through the down-regulation of cPLA2, COX-2, IκBα, p38 and MPO signaling in sPLA2 induced mice paw oedema

Eleusine coracana (L.) Gaertn (E. coracana) is one of the highest consuming food crops in Asia and Africa. E. coracana is a plant with several medicinal values including anti-ulcerative, anti-diabetic, anti-viral and anti-cancer properties. However, the anti-inflammatory property of E. coracana remains to be elucidated. Therefore, the objective of present study was to investigate the potential in isolated molecule from E. coracana via a combination of in vitro, in vivo and in silico methods. In this study, we have isolated, purified and characterized an anti-inflammatory molecule from E. coracana bran extract known as syringol. Purification of syringol was accomplished by combination of GC-MS and RP-HPLC techniques. Syringol significantly inhibited the enzymes activity of sPLA₂ (IC₅₀ = 3.00 µg) and 5-LOX (IC₅₀ = 0.325 µg) in vitro. The inhibition is independent of substrate concentration, calcium ion concentration and was irreversible. Syringol interacts with purified sPLA₂ enzymes as evidenced by fluorescence and molecular docking studies. Further, the syringol molecule dose dependently inhibited the development of sPLA₂ and λ-carrageenan induced edema. Furthermore, syringol decreases the expression of cPLA₂, COX-2, IκBα, p38 and MPO in edematous tissues as demonstrated by western blots. These studies revealed that syringol isolated from E. coracana bran may develop as a potent anti-inflammatory molecule.

Development of a New Route for Separating and Purifying 4-Ethyl-2-methoxyphenol Based on the Reaction Mechanism between the Chemical and Calcium Ion

Based on the characteristic that Ca²⁺ can react with 4-ethyl-2-methoxyphenol (EMP) to form a complexation with a phenol-calcium ratio of 4:1, a new extraction and purification method of EMP is developed for the first time in this work. At an optimum purification condition, 99.60% purity of EMP can be obtained through a reaction and decomposition operation. By combining a variety of characterizations, which consist of in situ Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance (NMR), inductively coupled plasma optical emission spectrometer (ICP-OES), gas chromatography-mass spectrometry (GC-MS)/flame ionization detector (FID), elemental analysis, and thermogravimetric analysis, the reaction mechanism of the coordination process is studied. It is demonstrated that there are three stages of the coordination reaction between Ca²⁺ and EMP. A neutralization reaction occurs in the first stage, while the second stage is a mixing reaction stage including neutralization and coordination reaction. When the reaction proceeds to the third stage, another coordination reaction occurs. Furthermore, phenol and ethanol are added as impurities in EMP. EMP with a purity of more than 99.50% can be obtained using this purification method. It confirms that this efficient method can achieve a good purification effect even for EMP solutions with complicated components.