New antioxidant flavonoid isolated from Leuzea carthamoides

A new natural flavonoid patuletin 3′-β-xylofuranoside was isolated from Leuzea carthamoides leaves. The antioxidant activity of this compound was evaluated by the DPPH radical assay and ferric reducing antioxidant power (FRAP) assay, and the results were compared with those for trolox and quercetin. DPPH radical scavenging activity of the tested compounds was expressed by the parameter EC₅₀: patuletin 3′-β-xylofuranoside (56.0 μM), trolox (27.8 μM), and quercetin (25.3 μM). The ferric reducing activity of the compounds was demonstrated as FRAP values at 4 and 60?min: patuletin 3′-β-xylofuranoside (28.4 μM, 35.8 μM), trolox (19.3 μM, 20.2 μM), and quercetin (54.3 μM, 79.9 μM). The structure/activity relationship of the flavonoid is also discussed. The results indicate significant antioxidant potency of patuletin 3′-β-xylofuranoside.     

Evaluation of natural antioxidants of Leuzea carthamoides as a result of a screening study of 88 plant extracts from the European Asteraceae and Cichoriaceae

In recently, there has been a great interest in natural antioxidants as bioactive components of food, nutraceuticals or potential drugs against several diseases. In our study, 88 extracts from various parts of plants from European Asteraceae and Cichoriaceae were assayed for radical scavenging activity by means of DPPH (1,1-diphenyl-2-picryl hydrazyl radical) test using the SIA (Sequential injection analysis) method developed for this purpose in our laboratory. DPPH radical scavenging activity of all tested plant extracts was evaluated according to the IC(50) parameter. 29 extracts exhibited IC(50) value lower than 0.1 mg/mL. The leaves of Leuzea carthamoides (IC(50) = 0.046 mg/mL) were chosen as the most promising sample for a subsequent phytochemical study, which resulted in isolation of seven natural compounds, namely, 4',5,7-trihydroxy-6-methoxyflavone (hispidulin) (1), 5, 7, 3', 4'- tetrahydroxyflavanone (eriodictyol) (2), 3',4',5,7-pentahydroxy-6-methoxyflavonol (patuletin) (3), eriodictyol-7-beta-glucopyranoside (4), 6-hydroxykaempferol-7-O-(6'-O-acetyl-beta-D-glucopyranoside) (5), 4-hydroxybenzoic acid (6) and 3,4-dihydroxybenzoic acid (protocatechuic acid) (7). Antioxidant activity of the isolated compounds was evaluated by DPPH test and ferric reducing antioxidant power (FRAP) test and compared with trolox and quercetin. Both tests evaluated the flavonoid (5) as the most active antioxidant. This result was confirmed by comparison with known data concerning the structure/activity relationships of flavonoids.     

Evaluation of natural antioxidants of Leuzea carthamoides as a result of a screening study of 88 plant extracts from the European Asteraceae and Cichoriaceae

In recently, there has been a great interest in natural antioxidants as bioactive components of food, nutraceuticals or potential drugs against several diseases. In our study, 88 extracts from various parts of plants from European Asteraceae and Cichoriaceae were assayed for radical scavenging activity by means of DPPH (1,1-diphenyl-2-picryl hydrazyl radical) test using the SIA (Sequential injection analysis) method developed for this purpose in our laboratory. DPPH radical scavenging activity of all tested plant extracts was evaluated according to the IC₅₀ parameter. 29 extracts exhibited IC₅₀ value lower than 0.1 mg/mL. The leaves of Leuzea carthamoides (IC₅₀ = 0.046 mg/mL) were chosen as the most promising sample for a subsequent phytochemical study, which resulted in isolation of seven natural compounds, namely, 4′,5,7-trihydroxy-6-methoxyflavone (hispidulin) (1), 5, 7, 3′, 4′- tetrahydroxyflavanone (eriodictyol) (2), 3′,4′,5,7-pentahydroxy-6-methoxyflavonol (patuletin) (3), eriodictyol-7-β-glucopyranoside (4), 6-hydroxykaempferol-7-O-(6″-O-acetyl-β-D-glucopyranoside) (5), 4-hydroxybenzoic acid (6) and 3,4-dihydroxybenzoic acid (protocatechuic acid) (7). Antioxidant activity of the isolated compounds was evaluated by DPPH test and ferric reducing antioxidant power (FRAP) test and compared with trolox and quercetin. Both tests evaluated the flavonoid (5) as the most active antioxidant. This result was confirmed by comparison with known data concerning the structure/activity relationships of flavonoids.     

Analysis of minor components in olive oil

Virgin olive oil is well known for its high content of phenolic substances that are thought to have health-promoting properties. These substances also contribute to the distinctive taste of the oil. In this study, tyrosol, vanillic acid, luteolin, and apigenin were identified and quantified by liquid chromatography mass spectrometry (LC-MS). In the seven samples analysed, tyrosol, the most abundant, was in the range of 1.4-29 mg/kg, vanillic acid was in the range of 0.67-4.0 mg/kg, luteolin was in the range of 0.22-7.0 mg/kg, and apigenin was in the range of 0.68-1.6 mg/kg. It was also shown that in olive oil, squalene can be analysed by using a refractive index detector. In the samples analysed, squalene occurred in the range of 3.9-9.6 g/l.     

Identification of minor components of coated vesicles by use of permeation chromatography

Coated vesicles are thought to be vehicles for the intracellular transport of membranes. Clathrin is the major protein component of coated vesicles. Minor components of these organelles can be identified in highly purified preparations if they can be shown to copurify with clathrin. To show copurification we have made use of the relatively uniform diameter of coated vesicles (50-150 nm) to fractionate conventionally purified coated vesicles according to size in glass bead columns of 200-nm pore size. We have found that bovine brain coated vesicles prepared by the standard procedure of Pearse can be contaminated with large membrane fragments that are removed by permeation chromatography on such glass bead columns. Gel electrophoretic analysis of column fractions shows that only three major polypeptide chains, and a family of polypeptides with molecular weights close to 100,000 are always in constant ratio to clathrin, and are unique to fractions containing coated vesicles. Two other major polypeptides that appear to be components of coated vesicles are also present in other membrane fractions. We have also used permeation chromatography to monitor artifactual membrane trapping during vesicle isolation. Pure radiolabeled synaptic vesicle membranes were added to bovine brain tissue before homogenization. Considerable amounts of the added radioactivity could be recovered in the fractions conventionally pooled in the preparation of coated vesicles. After permeation chromatography, the radioactivity in the coated vesicle peak was reduced essentially to background.     

Effect of minor components of virgin olive oil on topical antiinflammatory assays

Interest in the health-promoting effects of virgin olive oil, an important part of the "Mediterranean diet", prompted us to determine the antiinflammatory effects of erythrodiol, beta-sitosterol and squalene, identified as major components of the so-called "unsaponifiable fraction" of virgin olive oil, as well as of the phenolic compounds from the "polar fraction": oleuropein, tyrosol, hydroxytyrosol and caffeic acid. Their activities were compared to those of both, total unsaponifiable and polar fractions. This study was designed to analyse the antiinflammatory effect of these specific compounds from virgin olive oil on edema in mice induced by either arachidonic acid (AA) or 12-O-tetradecanoylphorbol acetate (TPA). The inhibition of the myeloperoxidase (MPO), marker enzyme of the accumulation of neutrophils in the inflamed tissue, was also investigated by the TPA model. The topical application of the olive oil compounds (0.5 mg/ear) produced a variable degree of antiinflammatory effect with both assays. In the auricular edema induced by TPA, beta-sitosterol and erythrodiol from the unsaponifiable fraction of the oil showed a potent antiedematous effect with a 61.4% and 82.1% of inhibition respectively, values not very different to that of the reference indomethacin (85.6%) at 0.5 mg/ear. The four phenolics exerted a similar range of inhibition (33-45%). All compounds strongly inhibited the enzyme myeloperoxidase, indicating a reduction of the neutrophil influx in the inflamed tissues. The strongest inhibitor of AA edema was the total unsaponifiable fraction which inhibition was 34%, similar to that obtained by the reference drug dexamethasone at 0.05 mg/ear. Among the phenolics, oleuropein also produced an inhibition of about 30% with the same dose, but all the other components were found less active in this assay. The anti-inflammatory effects exerted by both unsaponifiable and polar compounds might contribute to the potential biological properties reported for virgin olive oil against different pathological processes.     

Localization of minor protein components of the head of bacteriophage T4.

The bacteriophage T4 capsid contains a number of minor proteins that are required for head assembly but whose detailed function and position in the head are unknown. We have found that by systematically varying the conditions of extraction, some of these minor proteins can be removed while the main capsid structure is left substantially intact. Electron microscopic examination of the residual capsids showed that the extraction of the product of gene 20 is correlated with the loss of a plug that distinguishes one vertex position (presumably the tail attachment site) from the others. Extraction of the product of gene 24 is correlated with the loss of the other 11 (nonproximal) vertexes of the capsid. We further show that antibody to P24 binds specifically to the nonproximal vertexes of both T4 preheads and T4 phages. On the basis of our findings, we suggest that P20 is located at or near the tail attachment site of the capsid, whereas P24 forms the 11 nonproximal vertexes of preheads and P24 forms the nonproximal vertexes of the mature head.     

The efficient structure elucidation of minor components in heparin digests using microcoil NMR

The structural complexity and microheterogeneity of the glycosaminoglycans heparin and heparan sulfate make their characterization a daunting task. The methodology described herein utilizes a combination of enzymatic digestion, size-exclusion chromatography, strong anion-exchange HPLC, reverse-phase ion-pair ultrahigh performance liquid chromatography–mass spectrometry, and microcoil NMR for the efficient sequencing of heparin-derived tetrasaccharides. The high mass sensitivity of microcoil NMR makes this technique well suited for the characterization of mass-limited samples removing a bottleneck in the analysis workflow and permitting structural characterization of minor components isolated from a heparin enzymatic digestion. Complete characterization of one tetrasulfonated, five pentasulfonated isomers and two hexasulfonated tetrasaccharide sequences is described. To our knowledge, two of the identified minor tetrasaccharides are unique, and have not been previously reported: IdoA(2S)-GlcNS(6S)-IdoA(2S)-GlcNS(6S) and ΔUA(2S)-GlcNS(6S)-IdoA-GlcNS(6S).     

鞭角华扁叶蜂蜕皮甾类激素滴度的变化

用放射免疫分析法测定了鞭角华扁叶蜂Chinolyda flagellicornis末龄幼虫及滞育预蛹血淋巴中蜕皮甾类激素滴度。结果表明,末龄幼虫血淋巴中蜕皮甾类激素滴度在第2和4天各有一高峰;滞育预蛹血淋巴中保持一定滴度的蜕皮甾类激素,并随发育时期的不同有所波动;预蛹化蛹前一周血淋巴中蜕皮甾类激素滴度存在两个与变态相对应的峰值。表明鞭角华扁叶蜂的滞育与蜕皮甾类激素相关。     

The presence of minor histone components in the chromatin of Pisum sativum L. seedlings

Summary Two minor basic protein components (M1 and M2) were found in the histone extract from chromatin of pea seedlings. In the histone extract of pea cotyledons only one minor component (M1) was detected. These minor components show a high affinity for chromatin, have a molecular weight of 20.200 and 17.800 respectively and a basic amino acid composition. They are not contaminants of cytoplasmatic origin. Two similar minor components were found in the chromatin of Pisum arvense and Lens culinaris-seedlings, one component was present in the chromatin from cotyledons of these species.