摘要：
Tea (Camellia sinensis (L.) O. Kuntze) leaves are a major source of flavonoids that mainly belong to the flavan-3-ols or catechins and are implicated in a wide range of health benefits. Although the catechins in tea leaves were identified long ago, the regulatory mechanisms governing catechin biosynthesis remain unclear. In the present work, the dynamic changes of catechin levels and the expression profiles of catechin-related genes in albino tea plants were intensively examined. The amounts of most catechins decreased to their lowest levels in the albino phase, when epigallocatechingallate was the highest of the catechins compared to all catechins, and catechin the lowest. Enzyme assays indicated that phenylalanine ammonia-lyase (PAL) activity was positively correlated with the concentration of catechins (r = 0.673). Gene expression profiling by quantitative real-time reverse transcription-polymerase chain reaction showed that the transcript abundance of flavonoid biosynthetic genes followed a tightly regulated biphasic pattern, and was affected by albinism. These genes (PAL, C4H, 4CL, CHS, CHI, F3H, FLS, F3'H, F3'5'H, DFR, LAR, ANS and ANR) encode enzymes in flavonoid biosynthesis. The expression levels of PAL, F3H and FLS were correlated with the concentration of catechins and the correlation coefficients were -0.683, 0.687 and -0.602, respectively. Therefore, these results indicate that PAL might be a core regulator in the control of catechin biosynthesis in albino tea plants. (C) 2013 Elsevier Masson SAS. All rights reserved.
摘要：
Background: Renal accumulation of reactive carbonyl compounds (RCCs) has been linked to the progression of diabetic nephropathy. We previously demonstrated that carbonyl stress induces the formation of amino-carbonyl cross-links and sharply increases the content of beta-sheet-rich structures, which is the seed of insoluble aggregates formation, and tea catechin (-)-epigallocatechin 3-gallate (EGCG) can reverse this process in vitro and in vivo. In this study, methylated derivative (-)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3 '' Me) was hypothesized to neutralize carbonyl stress mediating the formation of insoluble ubiquitinated protein (IUP) aggregates, and reduce the early development of diabetic nephropathy. Methods and results: Diabetes was induced in mice by intraperitoneally injecting alloxan monohydrate (200 mg/kg/d) twice and administering EGCG3 '' Me by gavage for 15 d. Reagent case and western blot results showed that, in diabetic kidneys, the carbonyl proteins in the serum increased; and in insoluble protein fraction, 4-hydroxynonenal-modified proteins, IUP aggregates and p62 accumulated; FT-IR study demonstrated that the lipid content, anti-parallel beta-sheet structure and aggregates increased. EGCG3 '' Me treatment could effectively reverse this process, even better than the negative control treatment. Conclusions: EGCG3 '' Me exhibiting anti-beta-sheet-rich IUP aggregate properties, maybe represents a new strategy to impede the progression of diabetic nephropathy and other diabetic complications.
摘要：
GABAAα1 and GABAB1 receptor subunits are responsible for most behavioral, physiological and pharmacological effects of GABA receptors. We investigated the expression of GABAAα1 and GABAB1 receptor subunits in different tissues of gilts during late pregnancy in hot summer. The mRNA abundance of GABAAα1 receptor subunit in different tissues of gilts at d 90 and d 110 of gestation was as follows: d 90: brain > lung > liver > ovary > spleen > kidney > heart; d 110: brain > lung > spleen > liver > ovary > kidney > heart. And, the mRNA abundance of GABAB1 receptor subunit was as follows: d 90: spleen > lung > brain > kidney > ovary > liver > heart; d 110: spleen > lung > kidney > brain > ovary > liver > heart. The results in this trial indicated that the GABAAα1 receptor subunit was abundantly expressed in brain, while GABAB1 receptor subunit was abundant in spleen and lung of gilts during late gestation. There were no gestation stage-dependent effects on GABAAα1 and GABAB1 receptor subunits expression in all tissues.
摘要：
(−)-Epigallocatechin-3-gallate (EGCG), the most abundant catechin found in green tea, effectively reduces body weight and tissue and blood lipid accumulation. To explore the mechanism by which EGCG inhibits cellular lipid accumulation in free fatty acid (FFA) induced HepG2 cell culture, we investigated the proteome change of FFA-induced HepG2 cells exposed to EGCG using two-dimensional gel electrophoresis and mass spectrometry. In this study, 36 protein spots showed a significant change in intensity by more than 1.5-fold from the control group to the FFA group and from the FFA group to the FFA + EGCG group. Among them, 24 spots were excised from gels and identified by LC-MS/MS. In total, 18 proteins were successfully identified. All identified proteins were involved in lipid metabolism, glycometabolism, antioxidant defense, respiration, cytoskeleton organization, signal transduction, DNA repair, mRNA processing, iron storage, or were chaperone proteins. This indicated that these physiological processes may play roles in the mechanism of inhibition of lipid accumulation by EGCG in FFA-induced HepG2 cells. Western blotting analysis was used to verify the expression levels of differentially expressed proteins, which agree with the proteomic results. From the proteomic analysis, we hypothesized that EGCG reduced cellular lipid accumulation in FFA-induced HepG2 cells through the activation of AMP-activated protein kinase (AMPK) resulting from the generation of reactive oxygen species (ROS). The induction of ROS may be a result of EGCG regulation of the antioxidant defense system. Activation of AMPK shifted some FFA toward oxidation, away from lipid and triglyceride storage, and suppressed hepatic gluconeogenesis. The findings of this study improve our understanding of the molecular mechanisms of inhibition of lipid accumulation by EGCG in HepG2 cells.
关键词：
anti-malaria;artemisinin;stem internode;traditional Chinese medicine;transgene
摘要：
Transformation of Artemisia annua, which produces the sesquiterpenoid endoperoxide artemisinin widely used for the treatment of malaria, has been hampered by the low efficiency of adventitious shoot and root formation on a selective medium containing additional compounds for Agrobacterium decontamination. Here we identified several factors which were all shown to be of importance for optimization of Artemisia annua transformation. Results indicated that stem internodes showed better resistance capacity to Agrobacterium decontaminator than leaves did. Agrobacterium tumefaciens with an optical density (OD) value of 0.2-0.5 plus 100 μmol of acetosyringone per litre of solution gave the best transformation efficiency. Moreover, kanamycin at 30 mg/l in the culture medium was effective in suppressing the growth of non-transformed tissue. Furthermore, transgenic shoots required an early induction of rooting. In addition, dimethyl sulphoxide considerably improved the rooting of shoots. The present work provides rapid and reproducible transformation and regeneration of A. annua.
关键词：
Theanine;Caenorhabditis elegans;Stress resistance;Heat shock protein
摘要：
The beneficial effects of theanine in tea are reported on many aspects. Here we report that theanine can extend nematode Caenorhabditis elegans lifespan under stress. Theanine (100 mg/mL) significantly increased the mean longevity of C. elegans by 12.8% and 21.3% under heat stress and oxidative stress, respectively. However, theanine treatment did not increase survival of C. elegans under normal culture condition. Further studies showed that theanine mediated lifespan extension under heat stress was involved in heat shock protein-16.2 (HSP-16.2) up-regulating expression. (C) 2012 Elsevier Ltd. All rights reserved.
摘要：
High-speed counter-current chromatography was successfully applied to separate and purify bioactive ingredients from sweet potato leaves. Four caffeoylquinic acid derivatives and a mixture of two flavonoids were successfully obtained in one step. The caffeoylquinic acid derivatives were 3-O-caffeoylquinic acid (1), 4,5-di-O-caffeoylquinic acid (4), 3,5-di-O-caffeoylquinic acid (5), and 3,4-di-O-caffeoylquinic acid (6). The two-phase solvent system was composed of n-hexane\ethyl acetate\ethanol\water\acetic acid (1:5:2:4:0.1, v/v). The upper layer was used as the stationary phase, and the lower layer was used as the mobile phase. The flow rate was 1.5 mL/min, the revolution speed was 850 rpm, and the injection volume was 280 mg. The mixture of flavonoids was separated by preparative high-performance liquid chromatography into quercetin-3-O-β-D-galactopyranoside (2) and quercetin-3-O-β-D-glucoside (3). The purities of compounds 1–6 were 95.8% (5.4 mg), 99.5% (6.1 mg), 98.7% (15.1 mg), 97.8% (14.5 mg), 96.2% (10.3 mg), and 96.8% (7.8 mg), respectively, as determined by HPLC with a pulsed amperometric detector. The chemical structures were identified by electrospray ionization-tandem mass spectrometry and nuclear magnetic resonance imaging. The results showed the efficiency of the method in purifying bioactive compounds from sweet potato leaves, and compound 2 was separated from sweet potato for the first time.
