The aim of this study was to investigate the ultrasound-assisted alkaline extraction process and structural properties of hemicellulose from sugarcane bagasse pith. Response surface model (RSM) was established in order to optimize the extraction conditions for the highest hemicellulose yield based on the single-factor experiments. A maximum total hemicellulose yield of 23.05% was obtained under the optimal conditions of ultrasonic treatment time of 28 min, KOH mass concentration of 3.7%, and extraction temperature of 53 °C, and it evidently increased 3.24% compared without ultrasound-assisted extraction. The obtained hemicellulose was analyzed by Fourier transform infrared (FT-IR) spectroscopy. The monosaccharide composition and average molecular weight of hemicellulose were characterized by using ion chromatography (IC) and gel permeation chromatography (GPC). The results indicated that xylose was dominant component in water-soluble hemicellulose (WH, 69.05%) and alkali-soluble hemicellulose (AH, 85.83%), respectively. Furthermore, the monosaccharides (otherwise xylose) and uronic acids contents of WH were higher than that of AH. Weight average molecular weight of WH was 29923 g/mol, lower than that of AH (74,872 g/mol). These results indicate that ultrasonic-assisted alkaline extraction is an efficient approach for the separation of hemicellulose from sugarcane bagasse pith.
A fluorescent probe (Fluo-HMF) was developed via introduction of a furfural moiety into the fluorescein molecular skeleton, aiming at specially labeling cell membrane of mast cells. To illustrate its specificity, we designed and synthesized a series of fluorescent compounds based on fluorescein molecular skeleton. The fluorescent properties of Fluo-HMF were investigated, which were in accordance with theoretical calculations. Compared with other fluorescein derivatives, Fluo-HMF could specially label RBL-2H3 cells. The results suggested that Fluo-HMF could be used as a fluorescent probe for bioimaging on some related research of allergic mechanism.
Two alkaloids were screened from Uncaria rhynchophylla (UR) by MRGPRX2-HEK293/CMC model and showed anti-pseudo-allergic effects in vivo and in vitro, which may provide evidence for anti-pseudo-allergic effects and bioactivity development of UR.
5-HMF and two identified additional derivatives (II, III) in glucose injection were rapidly separated in less than 7 min for the first time by our normal phase high performance liquid chromatography. The results were more precise than the method adopted by pharmacopeias.
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