番石榴叶乙醇提取物的化学成分研究

采用多种色谱手段,对番石榴叶95%乙醇提取物的化学成分进行分离和纯化,并根据理化性质和光谱数据进行结构鉴定。从番石榴叶中分离得到18个化合物,分别为（+）-globulol（1）,clovane-2β,9α-diol（2）,2β-acetoxyclovan-9α-ol（3）,（+）-caryolane-1,9β-diol（4）, ent-T-muurolol（5）,clov-2-ene-9α-ol（6）,异植物醇（7）,柽柳黄素（8）,棉花素（9）,槲皮素（10）,山柰酚（11）,guajaverin（12）,avicularin（13）,chrysin 6-C-glucoside（14）,3’-O-methyl-3,4-methylenedioxyellagic acid 4’-O-β-D-glucopyranoside（15）,对羟基苯甲酸（16）,guavinoside A（17）和guavinoside B（18）。化合物 2~9,14~16为首次从该植物中分离得到。体外抗肿瘤活性筛选表明,番石榴叶95%乙醇提取物在60 mg·L^-1下对SW480细胞的抑制率达到61.3%。     

中药石斛黄酮活性成分研究进展

石斛是益胃生津,滋阴补虚的中药,有提高免疫力、抗氧化等功效,含有丰富的黄酮活性成分,具有较高保健价值.从多个石斛中共分离得到89个黄酮活性成分,主要分为黄酮类、黄烷酮类、黄酮醇类3种.其中黄酮类成分40个,苷元类型主要为芹菜素和圣金草素;黄烷酮类成分20个;黄酮醇类成分15个,苷元类型主要为山柰酚和槲皮素.铁皮石斛及个...     

Baicalin and Scutellarin Are Proteasome Inhibitors that Specifically Target Chymotrypsin‐like Catalytic Activity

Baicalin and scutellarin are the major active principal flavonoids extracted from the Chinese herbal medicines Scutellaria baicalensis and Erigeron breviscapus (Vant.) Hand‐Mazz. It has recently been reported that baicalin and scutellarin have antitumor activity. However, the mechanisms of action are unknown. We previously reported that some flavonoids have a specific role in the inhibition of the activity of proteasome subunits and induced apoptosis in tumor cells. To further investigate these pharmacological effects, we examined the inhibitory activity of baicalin and scutellarin on the extracted proteasomes from mice and cancer cells. Using fluorogenic substrates for proteasome catalytic subunits, we found that baicalin and scutellarin specifically inhibited chymotrypsin‐like activity but did not inhibit trypsin‐like and peptidyl‐glutamyl peptide hydrolyzing activities. These data suggested that baicalin and scutellarin specifically inhibit chymotrypsin‐like catalytic activity in the proteasome. Copyright © 2012 John Wiley & Sons, Ltd.     

香椿子总多酚对糖尿病小鼠的降血糖作用

目的:研究香椿子总多酚对糖尿病小的降血糖作用。方法:一次性ip链脲佐菌素制造糖尿病模型。将香椿子总多酚分低、中、高剂量组(60,801,00 mg·kg-1)连续ig 14 d,第15 d用葡萄糖氧化酶法测空腹血糖,同时测定多酚对正常小鼠血糖影响。糖尿病小鼠处死后取脏器,测定小鼠脏器指数、肝脏超氧化物歧化酶(SOD)活性,丙二醛(MDA)含量变化。结果:香椿子总多酚能降低链脲佐菌素诱导的糖尿病小鼠的血糖,对正常小鼠血糖没有降低作用。香椿子多酚能降低糖尿病小鼠肝脏脏器指数(P<0.05),降低肝脏MDA含量(P<0.05),增加SOD活性(P<0.05)。结论:香椿子多酚对链脲佐菌素所致糖尿病模型小鼠有降血糖作用。     

Protection of Total Flavonoid Fraction from Nervilia fordii on Lipopolysaccharide-induced Acute Lung Injury in Rats

Objective To investigate the effects of total flavonoid fraction (TFF) from Nervilia fordii on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats, and to explore their protective mechanism. Methods LPS-induced ALI model was established by LPS (5 mg/kg) injection via left cervical vein. Blood samples were collected from the cervical artery of all rats at 5 and 6 h after LPS challenge for arterial blood gas test and cytokines measurements, and pulmonary microvascular permeability (PMP), lung wet/dry weight ratio (W/D), and pathological features were observed. Results Phytochemical study showed that the TFF contained 67.3% of flavonoids expressed in rutin and three flavone glycosides. The TFF pretreatment (6.24 and 12.48 mg/kg) attenuated the partial arterial pressure of oxygen decline in blood significantly, and decreased the PMP and lung W/D ratio in ALI rats. In addition, the TFF (6.24 and 12.48 mg/kg) also ameliorated the LPS-induced lung damages including alveolar edema, neutrophils in?ltration, alveolar hemorrhage, and thickening of the alveolar wall. Furthermore, the treatment with the TFF (6.24 and 12.48 mg/kg) also down-regulated the levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and intercellular adhesion molecule-1 (ICAM-1), and up-regulated the level of anti-inflammatory cytokine IL-10 in serum of ALI rats simultaneously. Conclusion These results suggest that the TFF could protect LPS-induced ALI in rats, which may be mediated, at least in part, by adjusting the production of inflammatory cytokines including TNF-α, IL-6, ICAM-1, and IL-10.     

Inhibition of Inducible Nitric Oxide Synthase and Cyclooxygenase‐2 Expression by Phenolic Compounds from Roots of Rhododendron mucronulatum

The roots of Rhododendron mucronulatum Turzaninov have been used in Oriental traditional medicine for the treatment of dysuria, fever, increase of digestive activity and tonics in China and Korea. Activity guided isolation of the roots of Rhododendron mucronulatum Turzaninov has led to the isolation of three flavonoids, one flavan 3‐ol and one proanthocyanidin. Chemical investigation of the 80% Me₂CO extract from the roots of Rhododendron mucronulatum led to the isolation and identification of five compounds: taxifolin (1), taxifolin 3‐O‐β‐d ‐glucopyranoside (2), quercetin 3‐O‐α‐l ‐arabinofuranoside (3), (‐)‐epicatechin (4), procyanidin B‐3 (5). To investigate the antioxidative and antiinflammatory effects of these compounds, their 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activities and the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) in LPS‐stimulated HaCaT cells were also quantified by western blotting and their end products, nitric oxide (NO) and prostaglandin E₂ (PGE₂), respectively. Compounds (1–5) showed potent DPPH radical scavenging compared with positive controls (l ‐ascorbic acid). Also, compounds 1 and 2 dose‐dependently inhibited the expressions of inflammatory mediators, NO and PGE₂, suggesting they are promising candidates as antiinflammatory agents. Copyright © 2011 John Wiley & Sons, Ltd.     

Persimmon leaf flavonoid induces brain ischemic tolerance in mice

The persimmon leaf has been shown to improve cerebral ischemic outcomes; however, its mechanism of action remains unclear. In this study, mice were subjected to 10 minutes of ischemic preconditioning, and persimmon leaf flavonoid was orally administered for 5 days. Results showed that the persimmon leaf flavonoid significantly improved the content of tissue type plasminogen activator and 6-keto prostaglandin-F1 α in the cerebral cortex, decreased the content of thromboxane B2, and reduced the content of plasminogen activator inhibitor-1 in mice. Following optical microscopy, persimmon leaf flavonoid was also shown to reduce cell swelling and nuclear hyperchromatism in the cerebral cortex and hippocampus of mice. These results suggested that persimmon leaf flavonoid can effectively inhibit brain thrombosis, improve blood supply to the brain, and relieve ischemia-induced pathological damage, resulting in brain ischemic tolerance.     

Suppression of inflammatory responses after onset of collagen-induced arthritis in mice by oral administration of the Citrus flavanone naringin

Rheumatoid arthritis (RA) is closely related to the pathogenesis of tumor necrosis factor α in lesions. We investigated the suppressive effects of a Citrus flavanone naringin on inflammatory responses in mice with collagen-induced arthritis (CIA), a mouse model for RA. To investigate potential preventive and therapeutic effects of naringin, mice were given naringin orally three times a week from the second immunization with collagen (day 21) and from day 31, when symptoms of CIA had reached a plateau, respectively. In both cases, inflammation-related clinical scores for knee joints were significantly reduced by administration of naringin. Histological analyses demonstrated that representative phenomena, such as damage to interchondral joints, infiltration of inflammatory cells and pannus formation, were significantly depressed by treatment with naringin. In addition, increases in the expression of high-mobility group box-1 protein in the joints of mice with CIA were suppressed by naringin. These results suggest that oral administration of naringin might be effective for treating human patients with RA.     

Effect of Nitric Oxide on the Oxygen Metabolism and Growth of E. faecalis

Gastro-intestinal mucosal cells have a potent mechanism to eliminate a variety of pathogens using enzymes that generate reactive oxygen species and/or nitric oxide (NO). However, a large number of bacteria survive in the intestine of human subjects. Enterococcus faecalis (E. faecalis) is a Gram-positive bacterium that survives not only in the intestinal lumen but also within macrophages generating NO. It has been reported that E. faecalis generated the superoxide radical (O₂⁻). To elucidate the role of O₂⁻ and NO in the mechanism for the pathogen surviving in the intestine and macrophages, we studied the role and metabolism of O₂⁻ and NO in and around E. faecalis. Kinetic analysis revealed that E. faecalis generated 0.5 µmol O₂⁻/min/10⁸ cells in a glucose-dependent manner as determined using the cytochrome c reduction method. The presence of NOC12, an NO donor, strongly inhibited the growth of E. faecalis without affecting in the oxygen consumption. However, the growth rate of NOC12-pretreated E. faecalis in NO-free medium was similar to that of untreated cells. Western blotting analysis revealed that the NOC12-treated E. faecalis revealed a large amount of nitrotyrosine-posititive proteins; the amounts of the modified proteins were higher in cytosol than in membranes. These observations suggested that O₂⁻ generated by E. faecalis reacted with NO to form peroxinitrite (ONOO⁻) that preferentially nitrated tyrosyl residues in cytosolic proteins, thereby reversibly inhibited cellular growth. Since E. faecalis survives even within macrophages expressing NO synthase, similar metabolism of O₂⁻ and NO may occur in and around phagocytized macrophages.     

不同产地阳春砂总酚与总黄酮测定及抗氧化活性研究

目的:测定不同产地阳春砂总酚、总黄酮含量,比较抗氧化活性差异,为天然抗氧化剂的开发提供实验依据.方法:采用福林酚比色法测定总酚含量;采用硝酸铝比色法测定总黄酮含量;通过1,1-二苯基-2-三硝基苯肼(DPPH)自由基、羟自由基清除能力和还原能力评价砂仁抗氧化活性.结果:没食子酸线性范围为0.2～1.6mg/mL(r=0...