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Mn-doped scandium clusters have been systematically investigated using the density-functional approach. It was found that, starting from N = 6, the growth patterns of the ground-state structures of MnSc N clusters are dominated by octahedral structures with the Mn atom occupying the center of the host framework. The calculated results show that doping with Mn contributes to improving the stability of the scandium framework. The octahedral structure with the Mn atom occupying the center from N ≥ 6 has a relatively larger HOMO–LUMO gap compared with small-sized MnSc N clusters. Also, the largest oscillation of the energy gap occurs at N = 5 and 6. Moreover, the local peaks of N = 3, 5 and 8 of the energy gap are in agreement with the second-order energy differences. The encapsulated Mn atom, coupled with the antiferromagnetic alignment with N ≥ 6, reduces the magnetism of the host Sc N clusters in most cases. This is different from Mn doped into B n , Ge n , and Bi n clusters. The MnSc6 cluster not only has the smallest energy gap (about 0.01 eV), but also the largest magnetic moment of 5 µB of all of the MnSc N clusters. [ABSTRACT FROM AUTHOR]

Inducing protein degradation by proteolysis targeting chimera (PROTAC) has provided great opportunities for scientific research and industrial applications. Histone deacetylase (HDAC)-PROTAC has been widely developed since the first report of its ability to induce the degradation of SIRT2 in 2017. To date, ten of the eighteen HDACs (HDACs 1–8, HDAC10, and SIRT2) have been successfully targeted and degraded by HDAC-PROTACs. HDAC-PROTACs surpass traditional HDAC inhibitors in many aspects, such as higher selectivity, more potent antiproliferative activity, and the ability to disrupt the enzyme-independent functions of a multifunctional protein and overcome drug resistance. Rationally designing HDAC-PROTACs is a main challenge in development because slight variations in chemical structure can lead to drastic effects on the efficiency and selectivity of the degradation. In the future, HDAC-PROTACs can potentially be involved in clinical research with the support of the increased amount of in vivo data, pharmacokinetic evaluation, and pharmacological studies. [Display omitted] • Ten of the eighteen HDACs have been successfully degraded by PROTAC. • HDAC-PROTAC surpass traditional HDAC inhibitors in many aspects. • Rationally designing HDAC-PROTAC is a main challenge in development. [ABSTRACT FROM AUTHOR]

The biological activities of sulfated polysaccharides are related to the substitution positions of functional groups. In this study, regioselective sulfation of Artemisia sphaerocephala polysaccharides (S RS ASP) was prepared by using triphenylchloromethane (TrCl) as protecting precursor. FT-IR spectra and X-ray photoelectron spectroscopy (XPS) showed that SO 3− group (S 6+ , high binding energy of 168.7 eV) was widely present in sulfated polysaccharides. 13 C NMR spectroscopy showed that C-2 and C-3 substitution was occurred but not fully sulfation. Meanwhile, C-6 substituted signals near 65 ppm were not observed. The degree of substitution varied from 0.44 to 0.63 in S RS ASP which could be attributed to the low reactivity at secondary hydroxyl. Monosaccharide composition result showed a decrease in the ratio of mannose/glucose, indicating the change of chemical composition in sulfated polysaccharides. In size-exclusion chromatograph analysis, a decrease in molecular weight and broadening of molecular weight distribution of sulfated polysaccharides was also observed. It could be attributed to the hydrolysis of polysaccharide in the sulfated reaction. [ABSTRACT FROM AUTHOR]

In the present study, sulfated derivatives of Artemisia sphaerocephala polysaccharide (SASP) with high degree of substitution (DS) were synthesized by using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst in homogeneous conditions. It was found that DMAP/DCC showed marked improvement in DS of sulfated samples. Compared to sulfated derivatives without catalyst, the DS of SASP increased from 0.91 to 1.28 with an increment in dosage of DMAP from 0 to 10 mg. The influence of DMAP/DCC on the DS of sulfated derivatives was depended on the content of DMAP. The effect of DMAP might be due to its strong coordination to the hydroxy group. The results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated that SO 3 − group (S 6+ , binding energy of 172.3 eV) was widely present in sulfated polysaccharide molecules. 13 C NMR results indicated that C-6 substitution was predominant for sulfated polysaccharide when compared with other positions. In the sulfation reaction, a sharp decrease in M W was observed. DMAP/DCC was an effective catalyst system in sulfated modification of polysaccharide. [ABSTRACT FROM AUTHOR]

isolation, structure elucidation, and antiproliferative activities of two new triterpenoids along with eight known compounds [ABSTRACT FROM AUTHOR]