Phytochemical characterization and radical scavenger activity of flavonoids from Helichrysum italicum G. Don (compositae)

The glycosidic fraction of the flavonoids extracted from the flowering tops of the Helichrysum italicum G. Don was isolated, purified and characterized. This fraction was constituted by three compounds, which were assigned the structure of 4,2′,4′,6′-tetrahydroxychalcone-2′-glucoside, kaempferol-3-glucoside and naringenin-glycoside.Radical scavenger properties of the single glycosyl-flavonoids and of the in toto glycosidic fraction were tested with in vitro systems where different reactive oxygen species are generated (superoxide ions, hydroxyl radicals) and on lipid peroxidation induced by ADP/Fe²⁺ and NADPH or CCl₄ in rat liver microsomes. The formation of reactive oxygen species was detected by cytochrome c reduction, salicylic acid hydroxylation and hyaluronic acid depolymerization.The action of the glycosidic fraction on the release of TXB₂ and 12-HETE in human platelets, after collagen stimulation, was also evaluated.The glycosidic fraction inhibited in a dose dependent fashion lipid peroxidation in rat liver microsomes treated with ADP/Fe²⁺ or CCl₄. This effect is due to the ability of flavonoids to scavenge free radicals at different stages of the process (superoxide ions, hydroxyl and lipid peroxide radicals). The single glycosylflavonoids exhibited a different scavenger activity, depending on the oxygen species and the chemical structure of the compounds. No effect of the fraction was observed on TXB₂ and 12-HETE formation at 100 μm concentration.     

The activity of flavonoids extracted from Tanacetum microphyllum DC. (Compositae) on soybean lipoxygenase and prostaglandin synthetase

• 1.1. The in vitro effects of centaureidin and 5,3′-dihydroxy-4′-methoxy-7-carbomethoxyflavonol (Fig. 1), two anti-inflammatory flavonoids extracted from Tanacetum microphyllum DC., have been examined on both cyclooxygenase and lipoxygenase activity.
• 2.2. These flavonoids produced an inhibition of soybean lipoxygenase activity in a dose-dependent manner, with IC₅₀ values (20 and 29 μM respectively) similar to the reference drug.
• 3.3. The IC₅₀ values for the in vitro inhibition of cyclooxygenase activity by these flavonoids, were higher than those that produced lipoxygenase activity (318 and 60μM respectively).
• 4.4. These results suggest that the anti-inflammatory activity of our flavonoids may, at least in part, be due to the inhibition of leukotriene synthesis.
• 5.5. This is the first report of the biological activity in vitro of these compounds.

     

Effects of Helichrysum italicum extract on growth and enzymatic activity of Staphylococcus aureus

Helichrysum italicum G. Don (Compositae) is a shrub commonly found in dry, sandy and stony areas of Mediterranean regions. This plant is known for its anti-inflammatory, anti-allergic and antimicrobial activity. The aim of this study was to evaluate the effect of the diethyl ether extract on growth of Staphylococcus aureus (ATCC 6538P, MRSA and MSSA isolates) and the influence of subminimum inhibitory concentrations (subMICs) on some enzymes which are considered virulence factors. The results indicate that the H. italicum extract had an inhibitory effect on S. aureus strains reducing both their growth and some of the enzymes such as coagulase, DNAse, thermonuclease and lipase. Helichrysum italicum extract could be a novel antimicrobial agent, less toxic to human skin and tissues, worthy of further studies.     

DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of flavonoids obtained from some medicinal plants

A reactive oxygen species has been implicated in a range of human pathological diseases such as atherosclerosis and certain cancers. Flavonoids are reported to exhibit various biological activities, including antioxidative and free radical scavenging activities. Several flavonoids obtained from barley leaves, soybean and some medicinal plants, Silybum marianum, Sophorae Flos, Cinnamon, Ephedrae Herba and Scutellariae Radix, were tested for their DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. The structure-activity relationships suggested that not only the numbers of hydroxy group but also the position of hydroxy group might be important for mediating potent activity.     

Alkaloids of Vinca rosea L. (Catharanthus roseus G. Don) XXXVI: Isolation and characterization of new dimeric alkaloids.

In a continuing effort to study thoroughly the alkaloids of Catharanthus roseus, new dimeric alkaloids were isolated and characterized. Structures are proposed for leurocolombine and vinamidine based on UV, IR, PMR, high-resolution mass spectrometry, and CMR. Pseudovincaleukoblastine diol was identified by PMR and mass spectrometry. Leurocolombine exhibited antimitotic activity and marginal antitumor activity against the Ridgeway osteogenic sarcoma.     

Assessment of the anti-inflammatory activity and free radical scavenger activity of tiliroside

Three flavonoids, gnaphaliin, pinocembrin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their antioxidant and/or scavenger properties and in vivo in different models of inflammation. In vitro tests included lipid peroxidation in rat liver microsomes, superoxide radical generation in the xanthine/xanthine oxidase system and the reduction of the stable radical 1,1-diphenyl-2-pycryl-hydrazyl (DPPH). Acute inflammation was induced by application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to the mouse ear or by subcutaneous injection of phospholipase A(2) or serotonin in the mouse paw. Eczema provoked on the mouse ear by repeated administration of TPA was selected as a model of chronic inflammation. The flavonoids were assayed against sheep red blood cell-induced mouse paw oedema as a model of delayed-type hypersensitivity reaction. The most active compound, both in vitro and in vivo, was tiliroside. It significantly inhibited enzymatic and non-enzymatic lipid peroxidation (IC(50)=12.6 and 28 microM, respectively). It had scavenger properties (IC(50)=21.3 microM) and very potent antioxidant activity in the DPPH test (IC(50)=6 microM). In vivo, tiliroside significantly inhibited the mouse paw oedema induced by phospholipase A(2)(ED(50)=35.6 mg/kg) and the mouse ear inflammation induced by TPA (ED(50)=357 microg/ear). Pinocembrin was the only flavonoid that exhibited anti-inflammatory activity in the sheep red blood cell-induced delayed-type hypersensitivity reaction. However, only tiliroside significantly reduced the oedema and leukocyte infiltration induced by TPA. As in the case of other flavonoids, the anti-inflammatory activity of tiliroside could be based on its antioxidant properties, although other mechanisms are probably involved.     

Inhibition of leukocyte eicosanoid generation and radical scavenging activity by gnaphalin, a lipophilic flavonol isolated from Helichrysum picardii.

The lipophilic aglycone 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphalin) isolated from the aerial flowering parts of Helichrysum picardii Boiss. & Reuter (Asteraceae) was tested for interactions with the cyclo-oxygenase and 5-lipoxygenase pathways of arachidonate metabolism in stimulated rat peritoneal leukocytes, and for its effects on leukocyte granular enzyme release, cell viability and interactions with reactive oxygen species. Gnaphalin dose-dependently inhibited generation of the cyclo-oxygenase metabolite thromboxane B2 (IC50 = 39.9 +/- 3.9 microM), and of the 5-lipoxygenase metabolite leukotriene B4, although the potency was two-fold less (IC50 = 81.8 +/- 12.9 microM). At concentrations of 6 to 320 microM, gnaphalin did not affect secretion of the pro-inflammatory enzymes lysozyme, myeloperoxidase and beta-glucuronidase from the neutrophil secretory granules, and did not scavenge hydrogen peroxide or hypochlorous acid. However, gnaphalin effectively scavenged superoxide radicals generated in the hypoxanthine/xanthine oxidase system (IC50 = 40 microM) and by PMA-stimulated leukocytes (> 60% at 500 microM), directly inhibited xanthine oxidase (85% at 395 microM) and inhibited Fe(3+)-ascorbate-induced liposomal peroxidation (IC50 = 215 microM). Thus, like some other flavonoids found in medicinal herbs, gnaphalin possesses an array of potentially beneficial anti-eicosanoid and free-radical scavenging properties which may alongside other constituents contribute to the claimed medicinal properties of the plant from which it is derived.     

Sesquiterpene lactones from Lychnophora pohlii: neutrophil chemiluminescence inhibition and free radical scavenger activity

Excessive production of reactive oxygen species (ROS) by polymorphonuclear leucocytes (PMNLs) is thought to contribute to the pathology of many inflammatory diseases. Sesquiterpene lactones (STLs) seem to be important contributors to the anti-inflammatory activity of many species of Lychnophora (Asteraceae), which have been widely used in Brazilian folk medicine because of this pharmacological property. In this study, the inhibitory effects of three STLs isolated from Lychnophora pohlii (lychnopholide, centratherin and goyazensolide) on rabbit PMNL oxidative burst were evaluated by the luminol-enhanced chemiluminescence (CL-lum) assay. All STLs tested showed concentration-dependent inhibitory activity on CL-lum but were not cytotoxic to PMNLs (evaluated by lactate dehydrogenase release) under the assessed conditions. Moreover, goyazensolide, the most active STL, had no free radical scavenger property, as assessed by 1,1-diphenyl-2picrylhydrazyl radical assay, and had no inhibitory effect on the luminol-horseradish peroxidase-hydrogen peroxide chemiluminescence. Taken together, the results of this investigation suggest that the concomitant presence of methacrylate ester and hydroxyl groups contributes to a high inhibitory effect on PMNL oxidative metabolism. This effect was not mediated by free radical scavenger or cytotoxic effects, but probably by inhibition of enzymes involved in the signal transduction pathways of the ROS generation process.     

高效液相色谱法测定显脉獐牙菜中獐牙菜苦苷的含量

目的建立测定显脉獐牙菜中獐牙菜苦苷含量的高效液相色谱方法。方法C18（4.6 mm×200 mm,5μm）色谱柱,流动相为甲醇-水（25∶75）,流速为1.0 mL·min^-1,检测波长为239 nm,柱温为25℃。结果獐牙菜苦苷在1.52-15.22μg线性良好,相关系数r为0.999 95,平均回收率为97.8%,RSD小于3%（n=6）。结论本方法操作简便,分离效果好,灵敏度高,重现性好,可为显脉獐牙菜质量控制提供参考。     

In vivo effect of free radical scavenger hepatoprotective agents on superoxide dismutase (SOD) activity in patients

The in vivo effects of two hepatoprotective antioxidants (silymarin, and 4-amino-5-imidazole-carboxamide-phosphate) on the expression and activity of superoxide dismutase (SOD) enzyme were studied in erythrocytes from patients with alcoholic cirrhosis. In vivo treatment with any of the drugs markedly increased the SOD expression of lymphocytes as measured by flow-cytofluorimetry following staining with monoclonal anti-Cu, Zn-SOD-antibody and FITC-conjugated anti-mouse Ig, as well as erythrocyte and lymphocyte SOD activities. The data indirectly suggest that antioxidant activity might be one of the important factors in the hepatoprotective action of these agents.     

得自小根蒜及薤中的几种含氮化合物

从中药薤白的主要基源植物小根蒜（ＡｌｌｉｕｍｍａｃｒｏｓｔｅｍｏｎＢｕｎｇｅ）鳞茎中首次分得５种化合物。它们是腺苷（Ａｄｅｎｏｓｉｎｅ，１）、胸苷（Ｔｈｙｍｉｄｉｎｅ，２）、２，３，４，９－四氢－１－甲基－１Ｈ－吡啶骈［３，４－ｂ］吲哚－３－羧酸（２，３，４，９－ｔｅｔｒａｈｙｄｒｏ－１－ｍｅｔｈｙｌ－１Ｈ－ｐｙｒｉｄｏ［３，４－ｂ］ｉｎｄｏｌｅ－３－ｃａｒｂｏｘｙｌｉｃａｃｉｄ，３）、２，３，４，９－四氢－１Ｈ－吡啶骈［３，４－ｂ］吲哚－３－羧酸（２，３，４，９－ｔｅｔｒａｈｙｄｒｏ－１Ｈ－ｐｙｒｉｄｏ［３，４－ｂ］ｉｎｄｏｌｅ－３－ｃａｒｂｏｘｙｌｉｃａｃｉｄ，４）和丁香甙（Ｓｙｒｉｎｇｉｎ，５）．从另一种基源植物薤（Ａ．ｃｈｉｎｅｎｓｅＧ．Ｄｏｎ）鳞茎中分得腺苷（１）、色氨酸（Ｔｒｙｐｔｏｐｈａｎ，６）和化合物（４）．     

羊踯躅的化学成分研究

对羊踯躅植物花蕾的化学成分进行研究,应用多种色谱技术进行分离纯化、波谱技术鉴定其结构。从羊踯躅花蕾中分离并鉴定了15个化合物,分别为2E,4Z-脱落酸（1）,2α-羟基齐墩果酸（2）,齐墩果酸（3）,积雪草酸（4）,苯甲基糖苷（5）,邻苯二甲酸二丁酯（6）,β-谷甾醇（7）,牡荆素（8）,槲皮素（9）,硬脂酸（10）,rhodomollein Ⅰ（11）,rhodojaponin Ⅵ（12）,rhodomollein Ⅺ（13）,rhodojaponin Ⅱ（14）,kalmanol（15）。其中,化合物1 10为首次从羊踯躅植物中得到。     

Free radical scavenging activity of Eagle tea and their flavonoids

In this study, an online HPLC-DAD-MS coupled with 2,2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) assay was employed for evaluating free radical scavenging activity of Eagle tea and their active components. Twenty-three chromatographic peaks were detected, and nineteen components had free radical scavenging activity. Among them, eight compounds were identified as flavonoids (hyperin, isoquercitrin, quercitrin, quercetin, kaempferol), catechins, chlorogenic acid and epicatechin based on MS data and standard chromatographic characters.     

An Antimicrobial Principle from Sphaeranthus indicus L. (Family Compositae)

Abstract

A bicyclic sesquiterpene lactone has been isolated from the petroleum ether extract of the aerial part of the Indian Composite Sphaeranthus indicus. The compound deonstrated strong antimicrobial activity against Staphylococcus aureus, S. albus, Escherichia coli, Fusarium sp., Helminthosporium sp. and other microorganisms.     

铁扫帚化学成分研究

目的研究铁扫帚的化学成分。方法采用反复柱色谱方法进行分离，利用化合物的光谱学数据结合理化性质鉴定化合物的结构。结果分离并鉴定8个化合物：β-谷甾醇（Ⅰ）、正二十八烷醇（Ⅱ）、水杨酸（Ⅲ）、香草酸（Ⅳ）、山柰酚（Ⅴ）、桷皮素（Ⅵ）、山柰酚-3-O-β-D-葡萄糖苷（Ⅶ）、胡萝卜苷（Ⅷ）。结论化合物Ⅱ～Ⅷ为首次从该种植物中分离得到。     

Cardioselectivity of alpha-tocopherol analogues, with free radical scavenger activity, in the rat.

MDL74270 (6-acetyloxy-3,4-dihydro-N,N,N,2,5,7, 8-heptamethyl-2H-1-benzopyran-2-ethanaminium, 4-methylbenzenesulfonate) is a quaternary amine analogue of alpha-tocopherol with free radical scavenger properties. Rats were injected iv with [14C]MDL74270 (0.91 mg/kg), and whole blood and heart tissue were sampled. Five min after drug, the heart tissue/blood ratio (T/B) of radioactivity was 3.5, whereas at 1 hr it was 20.1 and remained at this value up to at least 6 hr. After iv administration the t 1/2 of radioactivity in blood was 6.3 hr, but po blood levels could not be quantified. The 0- to 96-hr urinary elimination of radioactivity was 39.9 +/- 5.7% of the dose after iv and only 1.2 +/- 0.4% after po administration, conversely, 44.7 +/- 5.2% was excreted in feces after iv and 79.1 +/- 17.4% after po administration. These results confirmed poor oral absorption of the compound. Tissue distribution of [14C]MDL74270 was compared with that of its tertiary amine analogue [14C]MDL74366 in rat heart, skeletal muscle, brain, and whole blood, after iv administration (1 mg/kg). The heart T/B was above 20, 1-6 hr after [14C]MDL74270, whereas it was less than 2 after [14C]MDL74366. Over the 1- to 6-hr time interval, skeletal muscle T/B varied from 1.8 to 5 compared with 1.5 to 0.6 for [14C] MDL74366. Brain T/B was higher after the tertiary amine compound. Results showed marked cardioselectivity of radioactivity after [14C] MDL74270. Differential centrifugation of heart homogenates showed that radioactivity was equally distributed between the major subcellular fractions studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

天茄子不同提取部位止血作用研究

目的研究天茄子不同提取部位的止血药理作用。方法依次以环己烷(T1)、水(T2)和乙醇(T3)为溶剂进行提取并对乙醇提取物依次用石油醚(T4)、乙酸乙酯(T5)、正丁醇(T6)进行萃取得到相应的部位以及水部位(T7),采用毛细玻管法、玻片法、剪尾法和测定血浆复钙时间检测其止血作用。结果 T3、T6、T7可缩短小鼠玻片法凝血时间,T3、T5、T6、T7可显著缩短小鼠毛细管法凝血时间,T3、T4、T5、T6、T7可显著缩短小鼠断尾法出血时间,T3、T6、T7可显著缩短小鼠血浆复钙时间。结论天茄子95%醇总提物、乙酸乙酯部位、正丁醇部位、水部位凝血效果显著,其中95%醇总提物、正丁醇部位、水部位凝血效果极其显著。