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Abstract: A general approach for the preparation of a library consisting of reactive rhodamine B (RhB) bioprobes based on ester or thioester linkages is described. The synthesis of this library proceeds fast and efficiently in one reaction step. Pure RhB ester chromophores are readily obtained directly from the reaction mixture following a simple and straight forward workup procedure without further HPLC purification required. A variety of functional groups are attached to the RhB scaffold yielding the functional chromophores in moderate to high yields with particular focus on introducing bioorthogonal substituents suitable for protein and peptide labeling. The approach reported herein provides a concise and practical route to access a variety of reactive RhB fluorophores that could be applied for various bioconjugation chemistries. [Copyright &y& Elsevier]

This paper, discussed the high-pressure homogenization (HPH) method for the preparation of large-leaf yellow tea polysaccharide conjugates (LYTP), and the effects of LYTP on physicochemical properties as well as antioxidant activity were investigated. The results show that HPH extraction time was less than 0.5 h, and extraction rate reached 15.4%, which was nearly 1.8 times faster than that of hot water extraction (HWE). Component analysis showed that the total polysaccharide content of LYTP was higher, while the contents of polyphenols and free protein were lower than those of HWE. It is noteworthy that the 9.1% free protein content at 40 MPa was lower than that of the Sevag method (11.2%), indicating that HPH can eliminate the cumbersome protein removal process and is more environmentally. The small-molecule polysaccharide content extracted by HPH increased, but the monosaccharide composition did not change. Meanwhile, HPH decreased the particle size of the polysaccharides, and the changes in the surface topography of LYTP upon homogenization were confirmed with scanning electron microscopy. As a consequence, HPH extraction can improve the antioxidant capacity of LYTP. HPH extraction is an efficient, rapid and environmentally method for the preparation of polysaccharides, which could be widely used in the food industry. [Display omitted] • High-pressure homogenization extraction of polysaccharide from large-leaf yellow tea. • This non-heating method is efficient, and can greatly shorten the extraction time. • The physicochemical properties of the tea polysaccharides were determined and compared. • The polysaccharides exhibited stronger antioxidant activities in vitro. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-high pressure (UHP) could change the primary and spatial structure of polysaccharides. • UHP could enhance the content of uronic acid and the bioactivity of polysaccharides. • UHP treatment was more efficient than Sevage's method in removing protein. In this study, the changes of structure and bioactivity of polysaccharides from large leaf yellow tea (LYTP) were investigated under ultra-high pressure (UHP). Native yellow tea polysaccharide were treatmented with ultra-high pressure (200, 400 and 600 MPa) for 5 min to yield yellow tea polysaccharide including 200 MPa-LYTP, 400 MPa-LYTP and 600 MPa-LYTP. It was found that the monosaccharide composition of LYTP changed significantly after the ultra-high pressure treatment. The molecular weight (Mw) of 200 MPa-LYTP (from 563.6 to 11.7 kDa), 400 MPa-LYTP (from 372.2 to 11.8 kDa) and 600 MPa-LYTP (from 344 to 11.6 kDa) sharply decreased upon ultra-high pressure treatment compared with LYTP (771.5 kDa), coincidentally particle size was also significantly reduced for 200 MPa-LYTP (23.2 %), 400 MPa-LYTP (40.2 %) and 600 MPa-LYTP (25.9 %). The results of the scanning electron microscope showed that ultra-high pressure also changed the surface and spatial morphology of LYTP. LYTP after ultra-high pressure treatment (UHP-LYTP) could further ameliorate alcohol-induced liver injury in mice. In addition, UHP treatment can more efficiently remove protein than the Sevages method. With the gradual removal of protein, its hepatoprotective effect increased. These findings demonstrated that UHP treatment could change the primary structure and spatial structure of LYTP, increase the content of acidic polysaccharides, and improve its bioactivity. [ABSTRACT FROM AUTHOR]