Flavolignans of Silybum marianum Fruit

The chemical composition of fruit from spotted milkweed [Silybum marianum(L.) Gaertn.] cultivated in Samara district was investigated using UV and ¹ H-NMR spectroscopies and mass spectrometry. Chemical transformations identify the flavolignans silybin, silydianin, silychristin, and 2,3-dehydrosilybin. The last was first described for spotted milkweed cultivated in Russia and CIS countries.     

Analysis of Flavonoids in Silybum marianum Fruit by HPLC

Flavonoids of spotted milkweed (Silybum marianumL. Gaerth.) were optimally separated using reverse-phase HPLC with isocratic elution by CH ₃ CN-H ₂ O over Separon SGX C ₁₈ . The flavolignans silybin, silydianin, silychristin, and the flavonoid taxifolin were identified in the chromatograms of extracts from this plant     

Complete isolation and characterization of silybins and isosilybins from milk thistle (Silybum marianum)

Complete separation, isolation, and structural characterization of four diastereoisomeric flavonolignans, silybins A (1) and B (2), and isosilybins A (3) and B (4) from the seeds of milk thistle (Silybum marianum) were achieved for the first time using a preparative reversed-phase HPLC method. In addition, three other flavonolignans, silychristin (5) isosilychristin (6) and silydianin (7), and a flavonoid, taxifolin (8) were isolated. Structures, including absolute stereochemistries of 1-4, were confirmed using 2D NMR and CD spectroscopy.     

New insight into the biosynthesis of flavanolignans in the white-flowered variant of Silybum marianum

It has been demonstrated that besides the known flavanolignan constituents of the white-flowered variant of Silybum marianum, (-)-silandrin A (3a) and (-)-isosilandrin A (4a); their trans-benzodioxane diastereomers, (-)-silandrin B (3b) and (-)-isosilandrin B (4b), are also produced by the plant. Moreover, the isolation of their cis-benzodioxane diastereomers, (-)-isocisilandrin (5) and cisilandrin (6), confirm that the previously proposed biosynthetic pathway involving a nonselective O-beta coupling is correct.     

水飞蓟全草不同部位的组成特征

为了考察水飞蓟全草不同部位的组成特征,采用不同的提取溶剂对水飞蓟的幼草、根、茎、叶、花、种子等不同部位提取后,通过高效液相色谱法(HPLC)进行分析。以Hypersil ODS2色谱柱(250 mm×4.6 mm, 5 μm)为分离柱,以50 mmoL/L磷酸二氢钾溶液和甲醇为流动相,梯度洗脱,检测波长为254 nm。在此条件下,水飞蓟不同部位的样品得到了很好的分离,发现不同部位组成差别很大,得到的组分数从幼草、种子、花、叶、根、茎依次减少。水飞蓟不同部位所含的组分极性有很大差别,不同提取方法得到的样品组成也有较大差别。实验结果可为水飞蓟全草的指纹图谱构建及应用开发提供实验依据。     

Pyrazinecarboxamides as potential elicitors of flavonolignan and flavonoid production in Silybum marianum and Ononis arvensis cultures in vitro

The effect of new synthetic pyrazinecarboxamide derivatives as potential elicitors of flavonolignan and flavonoid production in Silybum marianum and Ononis arvensis cultures in vitro was investigated. Both tested elicitors increased the production of flavonolignans in S. marianum callus and suspension cultures and flavonoids in O. arvensis callus and suspension cultures. Compound I, 5-(2-hydroxybenzoyl)-pyrazine-2-carboxamide, has shown to be an effective elicitor of flavonolignans and taxifoline production in Silybum marianum culture in vitro. The maximum content of silydianin (0.11%) in S. marianum suspension culture was induced by 24 h elicitor application in concentration of 1.159 × 10?3 mol/L. The maximum content of silymarin complex (0.08%) in callus culture of S. marianum was induced by 168 h elicitor application of a concentration 1.159 × 10?? mol/L, which represents contents of silydianin (0.03%), silychristin (0.01%) and isosilybin A (0.04%) compared with control. All three tested concentrations of compound II, N-(2-bromo-3-methylphenyl)-5-tert-butylpyrazin-2-carboxamide increased the flavonoid production in callus culture of O. arvensis in a statistically significant way. The best elicitation effect of all elicitor concentrations had the weakest c? concentration (8.36 × 10?? mol/L) after 168 h time of duration. The maximum content of flavonoids (about 5,900%) in suspension culture of O. arvensis was induced by 48 h application of c? concentration (8.36 × 10?? mol/L).     

Methyl jasmonate influence on silymarin production and plant stress responses in Silybum marianum hairy root cultures in a bioreactor

In this article our aim was to evaluate mass cultivation of S. marianum hairy roots in a bioreactor to produce silymarin. The effects of methyl jasmonate (MJ) elicitation on the accumulation of silymarin and the extent of the MJ-induced oxidative damage were investigated in bioreactor hairy root cultures of S. marianum. The growth rate of the bioreactor hairy root cultures was higher than that of those in a shake flask after 3 weeks. Silymarin accumulation was increased from 0.13?mg?g?1 DW in non-treated hairy roots to 0.22?mg?g?1 DW in hairy roots 72?h after 100?μM?MJ treatment. Guaiacol peroxidase and ascorbate peroxidase were activated by MJ?72?h after treatment, being 3.2- and 1.3-fold higher, respectively, than that of the control. An increase in enzymatic activity suggests increased scavenging of reactive oxygen species, indicating the tolerance to MJ stress. These results suggest that MJ elicitation is beneficial for silymarin production using bioreactor hairy root cultures.     

Expression Profiling of Flavonoid Biosynthesis Genes and Secondary Metabolites Accumulation in Populus under Drought Stress

Flavonoids are key secondary metabolites that are biologically active and perform diverse functions in plants such as stress defense against abiotic and biotic stress. In addition to its importance, no comprehensive information has been available about the secondary metabolic response of Populus tree, especially the genes that encode key enzymes involved in flavonoid biosynthesis under drought stress. In this study, the quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that the expression of flavonoid biosynthesis genes (PtPAL, Pt4-CL, PtCHS, PtFLS-1, PtF3H, PtDFR, and PtANS) gradually increased in the leaves of hybrid poplar (P. tremula × P. alba), corresponding to the drought stress duration. In addition, the activity and capacity of antioxidants have also increased, which is positively correlated with the increment of phenolic, flavonoid, anthocyanin, and carotenoid compounds under drought stress. As the drought stress prolonged, the level of reactive oxygen species such as hydrogen peroxide (H₂O₂) and singlet oxygen (O₂⁻) too increased. The concentration of phytohormone salicylic acid (SA) also increased significantly in the stressed poplar leaves. Our research concluded that drought stress significantly induced the expression of flavonoid biosynthesis genes in hybrid poplar plants and enhanced the accumulation of phenolic and flavonoid compounds with resilient antioxidant activity.     

Comparative Assessment of Phytoconstituents,Antioxidant Activity and Chemical Analysis of Different Parts of Milk Thistle Silybum marianum L.

Silybum marianum L. is a therapeutic plant belonging to the family Asteraceae, which has exhibited silymarin, a principal component used to cure various physiochemical disorders. The study appraised the phytochemical analysis, antioxidant activity and chemical analysis of an extract from the seed, stem and leaves. Qualitative and quantitative phytochemical analysis was evaluated by the Folin–Ciocalteu reagent method and aluminum chloride colorimetric method, respectively. While the antioxidant activity was determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and acetate buffer in ferric chloride (FRAP) assay, respectively, the chemical profile was evaluated by Gas Chromatography-Mass Spectrometry (GC-MS) assay. The study outcomes identified that alkaloids, glycosides, flavonoids, terpenoids, steroids and catcholic tannins were present in seed, stem and leaves extracts except for saponins and Gallic tannins. Whereas, phenols were absent only in seed extract. Quantitative analysis revealed the presence of phenols and flavonoids in appreciable amounts of 21.79 (GAE/g), 129.66 (QE/g) and 17.29 (GAE/g), 114.29 (QE/g) from the leaves and stem extract, respectively. Similarly, all extracts expressed reasonable DPPH inhibition (IC₅₀) and FRAP reducing power such as 75.98, 72.39 and 63.21% and 46.60, 51.40 and 41.30 mmol/g from the seeds, stem and leaves extract, respectively. Additionally, chemical analysis revealed the existence of 6, 8 and 9 chemical compounds from the seeds, stem and leaves extract, respectively, corresponding to 99.95, 99.96 and 98.89% of the whole extract. The chemical compound, Dibutyl phthalate was reported from all extracts while, Hexadecanoic acid, methyl ester and Silane, (1,1-dimethylethyl), dimethyl (phenylmethoxy) were reported only from the seed and leaves extract. Moreover, Methyl stearate was also a major compound reported from all extracts except for seed extract. It is demonstrable that extracts from different parts of S. marianum possess significant antioxidant activity, as well as valuable chemical compounds accountable for therapeutic effects that might be incorporated as an alternative to synthetic chemical agents.     

Synergistic Effects of Gamma Irradiation,Tensile Stress and Moisture on the Radiolysis of Silicone Foam

The present work involves the investigation of the synergistic effects of gamma irradiation, tensile stress and absorbed moisture on the radiolysis behaviors of silicone foams by experiments and theoretical simulations. For both the pristine and dehydrated samples, the permanent tensile set increases with the initial tensile strain. Further analysis uncovers that the dehydrated samples exhibit greater permanent tensile sets, lower further elongation and higher Young’s modulus than the counterpar...     

Chitosan Elicitation Impacts Flavonolignan Biosynthesis in Silybum marianum (L.) Gaertn Cell Suspension and Enhances Antioxidant and Anti-Inflammatory Activities of Cell Extracts

Silybum marianum (L.) Gaertn is a rich source of antioxidants and anti-inflammatory flavonolignans with great potential for use in pharmaceutical and cosmetic products. Its biotechnological production using in vitro culture system has been proposed. Chitosan is a well-known elicitor that strongly affects both secondary metabolites and biomass production by plants. The effect of chitosan on S. marianum cell suspension is not known yet. In the present study, suspension cultures of S. marianum were exploited for their in vitro potential to produce bioactive flavonolignans in the presence of chitosan. Established cell suspension cultures were maintained on the same hormonal media supplemented with 0.5 mg/L BAP (6-benzylaminopurine) and 1.0 mg/L NAA (α-naphthalene acetic acid) under photoperiod 16/8 h (light/dark) and exposed to various treatments of chitosan (ranging from 0.5 to 50.0 mg/L). The highest biomass production was observed for cell suspension treated with 5.0 mg/L chitosan, resulting in 123.3 ± 1.7 g/L fresh weight (FW) and 17.7 ± 0.5 g/L dry weight (DW) productions. All chitosan treatments resulted in an overall increase in the accumulation of total flavonoids (5.0 ± 0.1 mg/g DW for 5.0 mg/L chitosan), total phenolic compounds (11.0 ± 0.2 mg/g DW for 0.5 mg/L chitosan) and silymarin (9.9 ± 0.5 mg/g DW for 0.5 mg/L chitosan). In particular, higher accumulation levels of silybin B (6.3 ± 0.2 mg/g DW), silybin A (1.2 ± 0.1 mg/g DW) and silydianin (1.0 ± 0.0 mg/g DW) were recorded for 0.5 mg/L chitosan. The corresponding extracts displayed enhanced antioxidant and anti-inflammatory capacities: in particular, high ABTS antioxidant activity (741.5 ± 4.4 μM Trolox C equivalent antioxidant capacity) was recorded in extracts obtained in presence of 0.5 mg/L of chitosan, whereas highest inhibitions of cyclooxygenase 2 (COX-2, 30.5 ± 1.3 %), secretory phospholipase A2 (sPLA2, 33.9 ± 1.3 %) and 15-lipoxygenase (15-LOX-2, 31.6 ± 1.2 %) enzymes involved in inflammation process were measured in extracts obtained in the presence of 5.0 mg/L of chitosan. Taken together, these results highlight the high potential of the chitosan elicitation in the S. marianum cell suspension for enhanced production of antioxidant and anti-inflammatory silymarin-rich extracts.     

Structural determination of silymins A and B, new pentacyclic triterpenes from Silybum marianum, by 1D and 2D NMR spectroscopy

Silymins A (1) and B (2), the new pentacyclic triterpenes, have been isolated from ethyl acetate fraction of Silybum marianum and their structures assigned from 1H and 13C NMR spectra, DEPT and by 2D COSY, NOE and HMBC experiments.     

(+)-Silybin, a pharmacologically active constituent of Silybum marianum: fragmentation studies by atmospheric pressure chemical ionization quadrupole time-of-flight tandem mass spectrometry

The fragmentation behavior of (+)-silybin (1) and (+)-deuterosilybin (2), as well as of their flavanone-3-ol-type building blocks, such as 3,5,7-trihydroxy-2-phenyl-4-chromanone (3) and 2-(1,4-benzodioxolanyl)-3,5,7-trihydroxy-4-chromanone (4), were investigated by atmospheric pressure chemical ionization quadropole time-of-flight tandem mass spectrometry in the positive ion mode (APCI(+)-QqTOF MS/MS). The product ion spectra of the protonated molecules of 1 revealed a rather complicated fragmentation pattern with product ions originating from consecutive and competitive loss of small molecules such as H2O, CO, CH2O, CH3OH and 2-methoxyphenol, along with the A+- and B+-type ions arising from the cleavage of the C-ring of the flavanone-3-ol moiety. The elucidation of the fragmentation behavior of 1 was facilitated by acquiring information on the fragmentation characteristics of the flavanone-3-ol moieties and 2. The capability of the accurate mass measurement on the quadrupole time-of-flight mass spectrometer allowed us to determine the elemental composition of each major product ion. Second-generation product ion spectra obtained by combination of in-source collision induced dissociation (CID) with selective CID (pseudo-MS(3)) was also helpful in elaborating the fragmentation pathways and mechanism. Based on the experimental results, a fragmentation mechanism as well as fragmentation pathways for 1 and its flavanone-3-ol building blocks (3, 4) are proposed and discussed.     

硝普钠对镧胁迫下黑麦草幼苗叶片碳氮代谢和抗氧化系统的影响

为了探讨一氧化氮(NO)对镧胁迫下牧草生理响应的调节作用,采用水培方法,研究了NO供体硝普钠(SNP)对300μmol.L-1LaCl3胁迫下黑麦草幼苗生长、碳氮代谢和抗氧化系统的影响。结果表明:LaCl3胁迫下,喷施50μmol.L-1SNP能显著缓解幼苗生物量的下降,提高叶片超氧化物歧化酶和抗坏血酸过氧化物酶活性,降低超氧阴离子(O2.-)产生速率及H2O2和丙二醛含量;促进可溶性糖和可溶性蛋白质积累,提高二磷酸核酮糖羧化酶、磷酸烯醇式丙酮酸羧化酶、内肽酶和羧肽酶活性。表明NO可通过提高活性氧清除能力,维持碳氮代谢正常运转,从而缓解LaCl3胁迫对黑麦草生长的抑制作用。     

Effects of Vitamin E on the Activities of Protective Enzymes and Membrane Lipid Peroxidation in Leymus Chinensis under Drought Stress

Leymus chinensis seedlings were treated with 0.05--10 mmol/L vitamin E under osmotic stress in the presence of polyethylene glycol（PEG） as the stress reagent. The effects of the different concentrations of exogenous vitamin E on the activities of SOD, POD and free proline, and the MDA contents under drought stress were examined so as to ascertain the mechanism of Leymus chinensis resistance to drought stress and explore the possible preventive measures. The results indicate that the activities of SOD and POD decreased but the free proline and MDA contents increased as drought stress was accentuated, showing an enhancement of oxidative stress that may cause a decline in membrane stabilization. However, the activities of SOD and POD and the free proline content increased, whereas the MDA content reduced in Leymus chinensis pretreated with vitamin E in comparison with that of the control. This indicates that exogenous vitamin E enhanced the antioxidation of Leymus chinensis seedlings. It suggests that cytomembrane can be protected from damage by increasing the free proline content and the activities of SOD and POD that result in enhancing the drought resistance of Leymus chinensis seedlings.     

有机混合稀土化合物与有机锡化合物作为润滑添加剂的协同效应

用四球摩擦磨损试验机考察了环烷酸混合稀土、环烷酸亚锡及它们的复配物添加在26#白油中的摩擦学性能, 并用俄歇尔电子能谱研究了磨斑表面边界膜的化学组成. 结果表明: 环烷酸亚锡和环烷酸稀土在抗磨性能和减摩性能方面均存在明显的协同效应, 其复配物具有比ZDDP更好的抗磨减摩性能, 有望作为新型的高效多功能润滑添加剂在工业实际中得到应用, 复配物在摩擦表面形成的含稀土元素和锡元素的边界润滑膜是其具有良好摩擦学性能的主要原因.     

Influence of Synergistic Effects on Ion-Exchange Chromatographic Separation of Proteins

Formation of strong bonds between proteins and polyelectrolyte chains of ion-exchange sorbents gives rise to synergistic effects in multicomponent sorption and chromatographic separation of proteins. A series of heteronetwork-cross-linked polymeric bases with varied content of ionic groups was prepared. Consecutive sorption and cosorption of insulin and -lactalbumin on these materials were studied.     

Synergistic Effects of Magnetic Nanomaterials on Post-Digestate for Biogas Production

Digestate is characterized by high water content, and in the water and wastewater treatment settings, necessitates both large storage capacities and a high cost of disposal. By seeding digestate with four magnetic nanoparticles (MNPs), this study aimed to recover biogas and boost its methane potential anaerobically. This was carried out via biochemical methane potential (BMP) tests with five 1 L bioreactors, with a working volume of 80% and 20% head space. These were operated under anaerobic conditions at a temperature 40 °C for a 30 d incubation period. The SEM/EDX results revealed that the morphological surface area of the digestate with the MNPs increased as compared to its raw state. Comparatively, the degree of degradation of the bioreactors with MNPs resulted in over 75% decontamination (COD, color, and turbidity) as compared to the control system result of 60% without MNPs. The highest biogas production (400 mL/day) and methane yield (100% CH₄) was attained with 2 g of Fe₂O₄-TiO₂ MNPs as compared to the control biogas production (350 mL/day) and methane yield (65% CH₄). Economically, the highest energy balance achieved was estimated as 320.49 ZAR/kWh, or 22.89 USD/kWh in annual energy savings for this same system. These findings demonstrate that digestate seeded with MNPs has great potential to improve decontamination efficiency, biogas production and circular economy in wastewater management.     

苯并三唑和8-羟基喹啉对铜的缓蚀协同作用

通过电化学极化曲线和电化学阻抗谱研究了苯并三唑（BTA）和8 羟基喹啉（HQ）对铜的缓蚀协同作用， BTA和HQ复配使用后提高了电极的膜电阻，降低了电极的膜电容，增强了对铜腐蚀的抑制作用.通过MM2分子力学程序和PPP SCF量子化学方法优化计算了BTA和HQ的分子结构参数，分析讨论了它们之间的缓蚀协同效应.