Preparation from Lepidium meyenii Walpers using high-speed countercurrent chromatography and thermal stability of macamides in air at various temperatures.

Originally cultivated in the Peruvian Andes, Maca (Lepidium meyenii) is now widely consumed as functional food which is known for its functional characteristic like relieving fatigue and enhancing stamina. Macamides are the unique fatty acids with long-chain and N-benzylamides among the various constituents extracted from Maca. N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide, N-benzyl-(9Z, 12Z)-octadecadienamide, N-benzylhexadecanamide and N-benzyl-9Z-octadecenamide were isolated from crude Maca extracts in two steps by using a combination of high-speed countercurrent chromatography (HSCCC) and semi-preparative HPLC. The four macamides were identified by NMR, UV, HRMS and IR spectra. The thermal stability and autoxidative kinetics for N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide and N-benzyl-(9Z, 12Z)-octadecadienamide in the air were also studied at various temperatures and the apparent activation energies were 28.4 kJ/mol and 29.9 kJ/mol, respectively. The purity of the isolated macamides was up to 98% and the amount was enough for application as a reference substance.

[Short-term Effects of Different Grazing Intensities on Greenhouse Gas Fluxes in Semi-arid Grassland].

Grazing is one of the most important ways for managing grassland in northern China. Different studies have focused on the effects of grazing on the structure and function of ecosystems. Grazing affects the structure and function of soil via biological and physical processes, such as animal trampling, feeding, and excretion, which further affects N2O emissions. However, there is less research on greenhouse gases (GHGs) emissions by grazing intensities in semi-arid grassland ecosystems in northern China. In this study, four different grazing intensities were considered in the semi-arid grassland ecosystem of the typical agro-pastoral ecotone in northern China (Youyu, Shanxi). The influence of different grazing intensities on GHG fluxes was studied by measuring GHGs fluxes in the growing season with an opaque static chamber. The results showed that ① Grazing had no effect on CO2 and N2O fluxes during the first year of grazing treatment. ② However, grazing decreased soil water content (P<0.05), moderate grazing intensity decreased microbial biomass carbon (P<0.05), and moderate and heavy grazing intensities reduced microbial biomass nitrogen (P<0.05). ③ Significant positive correlations between CO2 flux and soil temperature and soil moisture were observed. The correlation between temperature and CO2 emissions was increased by grazing. ④ There was a significant positive correlation between soil temperature, soluble nitrogen, soil microbial biomass nitrogen, CO2 flux, and N2O flux. Our results indicated that GHG, regulated by soil microorganisms, was affected by soil temperature and moisture.

Determination and quality evaluation of green tea extracts through qualitative and quantitative analysis of multi-components by single marker (QAMS).

The quality of tea is mainly attributed to tea polyphenols and caffeine. In this paper, a new strategy for quality evaluation of green tea extracts was explored and verified through qualitative and quantitative analysis of multi-components by single marker (QAMS). Taguchi Design was introduced to evaluate the fluctuations of the relative conversion factors (fx) of tea catechins, gallic acid and caffeine to epigallocatechin gallate. The regression model (Sig.=0.000) and the deviations (R(2)>0.999) between QAMS and normal external standard method proved the consistency of the two methods. Hierarchical cluster analysis and canonical discriminant analysis were employed to classify 26 batches of commercial Longjing green tea extracts (LJGTEs) collected from different producers. The results showed a significant difference in component profile between the samples from different origins. The QAMS method was verified to be an alternative and promising method to comprehensively and effectively control the quality of LJGTEs from different origins.

Synthesis and cytotoxicity of triterpenoids derived from betulin and betulinic acid via click chemistry.

In this study, a series of triazole substituted betulin and betulinic acid derivatives was designed and synthesized via click chemistry at C-30 position. Eighteen target compounds were evaluated in vitro for their antitumor activities against leukemia cell-line HL-60. Seventeen compounds have not reported before. The cytotoxic experiment showed that most of betulinic acid derived triazoles have higher cytotoxic profile than betulinic acid. Among them, compound 30-[4-(4-fluorophenyl)-1H-1,2,3-triazol-1-yl] betulinic acid (7b) showed the best IC50 value (1.3 µM) against leukemia cell-line HL-60 (eight- to ninefold higher potency than betulinic acid).

[UV/Visible spectroscopic study of the beta-diketonate zirconium active species for olefin polymerization].

The method of UV/Visible absorption spectroscopy for olefin catalytic system was introduced in this paper, whose testing condition was much closer to the polymerization conditions. The actions of olefin polymerization catalyst (dbm)2 ZrCl2 with cocatalyst AlEt2 Cl (or MAO) were investigated by UV/visible absorption spectroscopy at atmosphere temperature. It was shown that the UV/Visible main absorption band of the zirconocenium, which can be related to the ligand to metal charge transfer bands (LMCT), varies greatly upon incremental addition of AlEt2 Cl or MAO. For the low molar ratios of Al/Zr in the catalytic system, there was the substitution of an electron withdrawing chlorine atom by a donating alkyl group. Then a hypsochromic shift of the initial catalyst absorption band, corresponding to the monomethylation of the catalyst, was observed in each catalytic system (dbm)2 ZrCl2/AlEt2 Cl (or (dbm)2 ZrCl2/MAO). On the contrary, further addition of AlEt2 Cl (or MAO) was accompanied by a continuous bathochromic shift of the maximal wavelength, which corresponding to the formation of more dissociated ionic active species. Then, there would be a coordination of monomer to the ionic active species.

A novel mutation in GATA4 gene associated with dominant inherited familial atrial septal defect.

OBJECTIVE: Atrial septal defect (ASD) is a common congenital heart disease (CHD). Although most cases are sporadic, familial cases have been reported. The transcription factors NKX2.5 and GATA4 play important roles in the pathogenesis of ASD. Mutations in either gene have been identified in familial cases of ASD. Here, we examine a Chinese family with isolated ASD to find out whether there is any mutation in NKX2.5 or GATA4 accounting for the etiology. METHODS: We identified kindred spanning 3 generations in which 8 of 31 (38%) individuals had ASD. One hundred seventy unrelated individuals were included as controls. Peripheral blood samples were collected and genomic DNA was extracted from the leukocytes. NKX2.5 and GATA4 were amplified by polymerase chain reaction (PCR) with specific primers. The sequences of PCR products were compared between affected members and unaffected members, as well as controls. RESULTS: Direct sequencing of NKX2.5 from the genomic DNA of family members failed to identify mutations, whereas sequencing of GATA4 identified an A-to-G transition at nucleotide 928 in exon 5 that predicted a methionine to valine substitution at codon 310 (M310V) in the NLS region. All affected members and a patriarch of the family who was recognized as a carrier exhibited this mutation, whereas the other unaffected family members or control individuals did not. This mutation has not been reported previously in either familial or sporadic cases of CHD. CONCLUSIONS: We identified a novel M310V mutation in GATA4 gene that is located in the NLS region and leads to hereditary ASD in a Chinese family. In this family, we identified a carrier with incomplete penetrance and 8 patients with variable expressivity. However, the mechanism by which this mutation contributes to the development of a congenital heart defect remains to be ascertained.