Sorptive potential of sunflower stem for Cr(III) ions from aqueous solutions and its kinetic and thermodynamic profile

The sorptive potential of sunflower stem (180-300 μm) for Cr(III) ions has been investigated in detail. The maximum sorption (≥85%) of Cr(III) ions (70.2 μM) has been accomplished using 30 mg of high density sunflower stem in 10 min from 0.001 M nitric and 0.0001 M hydrochloric acid solutions. The accumulation of Cr(III) ions on the sorbent follows Dubinin-Radushkevich (D-R), Freundlich and Langmuir isotherms. The isotherm yields D-R saturation capacity X_m = 1.60 ± 0.23 mmol g⁻¹, β = −0.00654 ± 0.00017 kJ² mol⁻², mean free energy E = 8.74 ± 0.12 kJ mol⁻¹, Freundlich sorption capacity K_F = 0.24 ± 0.11 mol g⁻¹, 1/n = 0.90 ± 0.04 and of Langmuir constant K_L = 6800 ± 600 dm³ mol⁻¹ and C_m = 120 ± 18 μmol g⁻¹. The variation of sorption with temperature (283-323 K) gives ΔH = −23.3 ± 0.8 kJ mol⁻¹, ΔS = −64.0 ± 2.7 J mol⁻¹ K⁻¹ and ΔG_298k = −4.04 ± 0.09 kJ mol⁻¹. The negative enthalpy and free energy envisage exothermic and spontaneous nature of sorption, respectively. Bisulphate, Fe(III), molybdate, citrate, Fe(II), Y(III) suppress the sorption significantly. The selectivity studies indicate that Cr(III), Eu(III) and Tb(III) ions can be separated from Tc(VII) and I(I). Sunflower stem can be used for the preconcentration and removal of Cr(III) ions from aqueous medium. This cheaper and novel sorbent has potential applications in analytical and environmental chemistry, in water decontamination, industrial waste treatment and in pollution abatement. A possible mechanism of biosorption of Cr(III) ions onto the sunflower stem has been proposed.     

Molecular Structure of 3-Hydroxy-4-Pyrone

Abstract

Aerial parts of Erigeron annuus and E. strigosus afforded 3-hydroxy-4-pyrone, the molecular structure of which was determined by single crystal X-ray diffraction.     

金属离子和热激处理对菊芋(Helianthus tuberosus L.)类金属硫蛋白基因htMT2表达的影响

使用不同金属离子及热激对菊芋进行了处理，并对菊芋不同组织器官中类金属硫蛋白基因(htMT2)mRNA水平的变化进行了研究．结果表明，htMT2在根中不表达，而且其表达不受金属离子的影响．Cu^2 降低叶中htMT2的表达，Cu^2 浓度与茎、叶中的htMT2 mRNA水平呈负相关性．在低浓度范围内，Zn^2 浓度与茎、叶中的htMT2 mRNA水平呈正相关性，而在高浓度范围内，Zn^2 浓度与htMT2 mRNA水平呈负相关性．Ca^2 对叶中htMT2表达的影响与Zn^2 的作用相似，但Ca^2 诱导茎中htMT2 mRNA水平升高．热激处理对不同组织中htMT2的表达无显著影响．研究的结果表明，htMT2表达受金属离子影响的特征与植物MT基因一致，进一步证实了我们前期工作中分离到的htMT2是一个新的植物MT基因．     

Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography–Electron Spray Ionization–Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the “raw material” to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC–ESI–MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.     

Enantioselective synthesis of heliannuol E; structural consideration of natural molecule

Heliannuol E 1, isolated from Helianthus annuus L. cv. SH-222, was successfully synthesized in both optically active forms, by novel ring-expansion reaction of the corresponding spirodienone derivatives 8 and 17, which were produced from 7 and 16 under anodic oxidation conditions. The absolute structure of the natural product was determined to have R-configuration at the benzylic position.     

A new lipophilic monosaccharide from Erigeron annggs

A new lipophilic monosaccharide,erigearide A(1),was isolated from the aerial parts of Erigeron annuus(Lima.)Pers.Its structure was elucidated by analysis of spectroscopic evidence.     

Chemical Composition and Antimicrobial and Antioxidant Activities of Essential Oil of Sunflower (Helianthus annuus L.) Receptacle

Sunflower (Helianthus annuus L.) contains active ingredients, such as flavonoids, alkaloids and tannins. Nevertheless, few studies have focused on essential oil from the receptacle of sunflower (SEO). In this work, we investigated the chemical composition and antimicrobial and antioxidant activities of SEO. The yield of SEO was about 0.42% (v/w) by hydrodistillation. A total of 68 volatile components of SEO were putatively identified by gas chromatography–mass spectrometry (GC-MS). The main constituents of SEO were α-pinene (26.00%), verbenone (7.40%), terpinolene (1.69%) and α-terpineol (1.27%). The minimum inhibitory concentration (MIC) of SEO against P. aeruginosa and S. aureus was 0.2 mg/mL. The MIC of SEO against S. cerevisiae was 3.2 mg/mL. The MIC of SEO against E. coli and Candida albicans was 6.4 mg/mL. The results showed that SEO had high antibacterial and antifungal activities. Three different analytical assays (DPPH, ABTS and iron ion reducing ability) were used to determine the antioxidant activities. The results showed that SEO had antioxidant activities. To summarize, the results in this study demonstrate the possibility for the development and application of SEO in potential natural preservatives and medicines due to its excellent antimicrobial and antioxidant activities.     

Helivypolide G. A novel dimeric bioactive sesquiterpene lactone

In the course of our ongoing research for new allelochemicals from Helianthus annuus, a novel dimeric bioactive sesquiterpene lactone, helivypolide G has been isolated and characterized from the medium polar active fractions of the leaves of cultivar variety Stella. The monomers are connected through carbons C-15 of each unit and an oxygen bridge, forming an enolic oxane ring.     

A New System of Multiple Emulsions with Lamellar Gel Phases from Vegetable Oil

Emulsions are excellent pharmaceutical vehicles used in both the pharmacy and cosmetic industries. Vegetable oils have several effects/benefits on skin and can be used in emulsions to release principal active components for cosmetic purposes. Herein, multiple W/O/W emulsions were formulated in a one-step emulsification method, and the resulting anisotropic structures were characterized by x-ray diffraction measurements. The multiple emulsions obtained were stable and maintained their anisotropic structures over 2 years. WAXS (wide-angle x-ray scattering) measurements of these emulsions suggested that the carbon chains of the surfactant around the globules are disposed in a gel network phase. Furthermore, SAXS (small-angle x-ray scattering) measurements indicated that the surfactant is organized in lamellar layers around the globules. Thus, for the first time, we demonstrated that stable lamellar gel phase multiple emulsions can be made from vegetable oils. In addition to having the advantage of being prepared in one step, these emulsions have desirable characteristics that can be used in the cosmetic industry as natural active principles with low surfactant concentration and the unique features of multiple emulsions with gel phases.     

Ceramides Isolated from Helianthus annuus L.

Three new compounds (2R)‐2‐hydroxy‐N‐[(2S,3S,4R,10E)‐1,3,4‐trihydroxyicos‐10‐en‐2‐yl]docosanamide ( 1 ), (2R,3R)‐2,3‐dihydroxy‐N‐[(2S,3S,4R,10E)‐1,3,4‐trihydroxyicos‐10‐en‐2‐yl]docosanamide ( 2 ), N‐(2‐phenylethyl)tetracosanamide ( 3 ), together with a known ceramide, (2R)‐N‐[(2S,3S,4R,8E)‐1‐(β‐D ‐Glucopyranosyloxy)‐3,4‐dihydroxyoctadec‐8‐en‐2‐yl]‐2‐hydroxyhexadecanamide ( 4 ), were isolated from acetone extract of flower disc of Helianthus annuus L. The structures were identified on the basis of chemical and spectroscopic methods.