In vitro wound healing properties,antioxidant activities,HPLC–ESI–MS/MS profile and phytoconstituents of the stem aqueous methanolic extract of Dracaena reflexa Lam

Column chromatography of the stem aqueous methanolic extract of Dracaena reflexa Lam. (DRSE) led to the isolation of five flavonoids, one phenolic glycoside, one triterpenoid and two steroidal saponins. Furthermore, 44 compounds were tentatively identified in the phytoconstituent profile of DRSE using HPLC–ESI–MS/MS. The antioxidant activity of DRSE was evaluated. In a DPPH radical scavenging assay, DRSE exhibited an IC₅₀ value of 311.6 ± 10.10 μg/ml compared with the IC₅₀ value of the standard Trolox (24.42 ± 0.87 μg/ml). The antioxidant activities of DRSE using ABTS assay and ferric reducing antioxidant power assay were 326.63 μm Trolox equivalents/mg extract and 208.67 μm Trolox equivalents/mg extract, respectively. The wound-healing activity of DRSE was studied by the scratch assay using Human Skin Fibroblast cells. After 24 h DRSE (at 10 and 20 μg/ml) decreased the wound width to 0.55 ± 0.37 and 0.47 ± 0.55 mm, respectively, compared with the wound width in the control cells (0.77 ± 0.17 mm). This result suggested that DRSE improved the wound-healing process by inducing the migration of fibroblasts. Moreover, a docking study was performed to evaluate the binding affinity of the identified phytoconstituents toward GSK-3β relative to the co-crystalized inhibitor and curcumin with the possible involvement of this pathway in the wound-healing activity of the extract.     

Chemical profile by LC–MS/MS,GC/MS and antioxidant activities of the essential oils and crude extracts of two Euphorbia species

In this study, it was aimed to investigate the chemical composition and antioxidant activities of two Euphorbia species. The major component of the fatty acid compositions obtained from the petroleum ether extracts was identified as palmitic acid for Euphorbia gaillardotii and Euphorbia macroclada. The main constituents of the essential oils were identified as arachidic acid for E. gaillardotii and tetratetracontane for E. macroclada. Among the 27 studied compounds, hesperidin, rutin, hyperoside and quinic, malic, gallic and tannic acids were found to be the most abundant compounds in the two Euphorbia species. The methanol extracts of E. gaillardotii and E. macroclada showed strong antioxidant activity in all tested methods. Particularly, IC₅₀ values of E. macroclada methanol extract that was the richest in terms of total phenolic-flavonoid contents were found to be lower than α-tocopherol and butylated hydroxytoluene in β-carotene bleaching, 2,2-diphenyl-1-picrylhydrazyl free and ABTS cation radical scavenging methods.     

Characterization of the Phytochemical Profiles and Biological Activities of Ajuga chamaepitys subsp. chia var. chia and Ajuga bombycina by High-Performance Liquid Chromatography–Electrospray Ionization–Tandem Mass Spectrometry (HPLC–ESI–MSn)

This study investigates into the pharmacological potential of three solvent extracts (ethyl acetate, methanol, and water) of two Ajuga species (Ajuga chamaepitys subsp. chia var. chia and Ajuga bombycina) based on their antioxidant activity and enzyme inhibitory effects along with establishing the phytochemical profile. Spectrophotometric and high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MSⁿ) were used to determine the total and individual phytocompounds, respectively. Antioxidant potential was assessed using different assays such as DPPH, ABTS, CUPRAC, FRAP, phosphomolybdenum, and metal chelation. Enzyme inhibitory effects were studied against acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase. The aqueous extract of both plants showed better ABTS scavenging, FRAP, and metal chelating activities. The methanol extracts displayed the highest tyrosinase inhibitory and antioxidant activity in the phosphomolybdenum assay while the ethyl acetate extracts of both plants showed better butyrylcholinesterase (BChE), α-amylase, and α-glucosidase inhibition. The total phenolic content was highest in the aqueous extract of A. chamaepitys while the methanolic extract of A. bombycina showed the highest flavonoid content. Identification by HPLC–ESI–MSⁿ revealed the presence of some individual compounds including phenolic acids, flavonoids, iridoid glycosides, phenylethanoid glycosides, and other compounds. To conclude, both A. chamaepitys and A. bombycina can be considered as rich sources of phytocompounds to manage chronic diseases.     

Determination of acetylcholinesterase and α-glucosidase inhibition by electrophoretically-mediated microanalysis and phenolic profile by HPLC-ESI-MS/MS of fruit juices from Brazilian Myrtaceae Plinia cauliflora (Mart.) Kausel and Eugenia uniflora L.

Abstract

Alzheimer’s disease and diabetes mellitus are contemporary diseases of great concern. Phenolic compounds are linked to several health benefits and could lead to novel strategies to combat these ailments. The objective of this study was to evaluate by electrophoretically-mediated microanalysis the potential inhibitory activity of the fruit juices from Plinia cauliflora (“jaboticaba”) and Eugenia uniflora (“pitanga”) toward acetylcholinesterase (AChE) and α-glucosidase, target enzymes in strategies for the treatment of these diseases. The phenolic profiles of the samples were also investigated. Jaboticaba and pitanga juices inhibited 85.90?±?1.73 and 52.67?±?1.24% of AChE activity at 5?mg mL^?1, and 57.91?±?2.60 and 69.47?±?2.89% of α-glucosidase activity at 1?mg mL^?1, respectively. Total phenolic content of the juices were 303.54?±?28.28 and 367.00?±?11.42 mgGA L^?1, respectively. The observed inhibitory activity can be explained, at least in part, by the presence of the phenolic compounds.     

Chemical composition,antioxidant and antiproliferative activities of essential oil from rhizome and leaves of Curcuma mutabilis Škorničk., M. Sabu & Prasanthk., endemic to Western Ghats of India

Abstract

Hydro-distilled essential oils, from fresh rhizomes and leaves of Curcuma mutabilis ?korni?k., M.Sabu & Prasanthk., characterized by GC–MS revealed the presence of thirty three and twenty three compounds therein respectively. Whilst estrone methyl ether (3-Methoxyestra-1,3,5(10)-trien-17-one) was the major component in rhizome oil (47.35%), sesquiterpene hydrocarbons predominated as the major group (63.92%) in leaf oil with a higher preponderance of β-caryophyllene (25.48%), β-farnesene (19.47%) and α-humulene (11.01%). Weak antioxidant activities observed in these oils determined by DPPH and ABTS methods were apparently influenced both by the oil composition and the assay conditions. Rhizome oil showed higher antiproliferative activity than leaf oil against leukemic K562 (IC₅₀-6.8µg/mL) and colorectal HCT116 (IC₅₀-8.5µg/mL) cancer cell lines. This first report reveals composition and biological activities of essential oils from C. mutabilis.     

Heat capacity by differential scanning calorimetry and thermodynamic functions of BaCe0.8Gd0.1Y0.1O2.9 in the temperature range of 166–790 K

Journal of Thermal Analysis and Calorimetry - In the present study, the heat capacities of barium cerate doped by gadolinium and yttrium oxides were measured for the first time in the temperature...     

Enrichment of flavonoid-rich extract from Bidens bipinnata L. by macroporous resin using response surface methodology,UHPLC–Q-TOF MS/MS-assisted characterization and comprehensive evaluation of its bioactivities by analytical hierarchy process

The extract of Bidens bipinnata L. exhibited wide spectrum of bioactivities owing to the presence of flavonoids. In this study, a purification process was developed to enrich the flavonoid-rich extract from B. bipinnata L. (BBTF). AB-8 resin was selected for the purification of total flavonoids. Response surface methodology coupled with Box–Behnken design was employed to optimize the purification condition; it was optimized as pH 5.1, volume of ethanol 80 ml, flow rate of ethanol 1.8 bed volume per hour (BV/h) and concentration of ethanol 76.0%. The total flavonoid content of BBTF was 56.48% under the optimal conditions. The identification of flavonoids in BBTF was conducted using UHPLC–ESI-Q-TOF MS. A total of 14 compounds, including 12 flavonoids, were identified in BBTF. Finally, the in vitro antioxidant activities, α-glucosidase and α-amylase inhibitory activities of BBTF were comprehensively analyzed by an analytical hierarchy process. The results indicated that it exhibited higher bioactivities than the crude extract. These findings suggested that the optimized process could significantly enhance the purity of flavonoids and their bioactivities. This study showed a comprehensive analysis of a total flavonoid extract of B. bipinnata L. for the first time, which could provide a useful approach for its purification process and quality control as well as bioactivities.     

Clathrate formation of Diels–Alder adduct of phencyclone and acenaphthylene. Key role of CH/π and bidentate CH/O interactions of the phenanthrene ring in construction of host framework

Two clathrate hosts (3a and 3b) were synthesized via the Diels–Alder reaction of phencyclone (1a) and tetracyclone (1b) with acenaphthylene (2), and the clathrate formation properties of these hosts towards a variety of organic guests were investigated. In the presence of aprotic solvents (i.e., aromatic, ketonic and etheric solvents), host 3a formed inclusion complexes with a 2:1 stoichiometric host/guest ratio, whereas 3b primarily formed 1:1 complexes. The desolvation temperatures of the 3a·guest complexes were extremely high in comparison to the boiling points of the pure guest liquids and were also much higher than those of the corresponding 3b·guest complexes, which contain the conformationally flexible stilbene moiety. Structural analyses of the 3a·guest complexes (i.e., 3a·benzene, 3a·toluene, 3a·1,4-dioxane, 3a·acetone and 3a·pentan-3-one) show that the aromatic CH/π (edge-to-face) interactions between phenanthrene and the acenaphthene ring as well as the interaction of the ‘bidentate’ CH/O hydrogen bond between the phenanthrene-ring hydrogen and the bridged carbonyl oxygen play a key role in the construction of the characteristic host ‘column’ structures. The guest molecule of the 3a·benzene complex is held between the stacking columns by aromatic CH/π interactions of the acenaphthene rings of adjacent host molecules. The stable clathrate formation of 3a is discussed based on X-ray structural analyses of six clathrates and PM6 molecular orbital calculations for the clathration model of 3a·benzene.     

Lavandin (Lavandula × intermedia Emeric ex Loiseleur) essential oil from Spain: determination of aromatic profile by gas chromatography–mass spectrometry,antioxidant and lipoxygenase inhibitory bioactivities

Lavandin (Lavandula × intermedia Emeric ex Loiseleur) essential oils (EOs), from Abrial, Super and Grosso cultivars, cultivated and extracted in the South East of Spain, were analysed by using GC/MS to determine their composition, in both relative (peak area) and absolute (using standard curves) concentrations. Linalool (34–47%), linalyl acetate (17–34%), camphor (4–9%) and eucalyptol (3–7%) were determined as the main molecules. This characterisation was completed with the enantioselective gas chromatography, where ( ? )-linalool, (+)-camphor and ( ? )-linalyl acetate were determined as the main components. Antioxidant activity was evaluated positively by several methods: activity against free radicals, chelating and reducing power, probably due to linalool and linalyl acetate. Mild inhibitory activity on lipoxygenase was observed supporting potential anti-inflammatory activity, mainly due to linalool and camphor. These properties support the potential use of L. × intermedia essential oils as natural cosmetic and natural pharmaceutical ingredient to fight several skin diseases.     

Comment on “Surface thermodynamics reconsidered. Derivation of the Gokhshtein relations from the Gibbs potential; and a new approach to surface stress” by Stephen Fletcher

The present article comments on the article of Stephen Fletcher (Journal of Solid State Electrochemistry Volume 18, Issue 5, pp 1231–1238). The analysis deals with the validity of equation (31 or 40) of the latter for an ideally polarisable interface.     

Complex of Cu<Superscript>II</Superscript> with a chiral Schiff base (H<Subscript>2</Subscript>L) derived from the natural monoterpene (+)-6h-pinene. Synthesis and the properties of the complex and its solvate with acetonitrile. Crystal structure of [Cu(HL)Cl]•H<Subscript>2</Subscript>O

A reaction of CuCl₂ with a chiral Schiff base (H₂L) derived from (+)-6h-pinene leads to paramagnetic complex Cu(HL)Cl (1) (fu_eff = 2.03 fuB) and solvate Cu(HL)Cl•MeCN (2) (fueff = 1.87 fuB). Monocrystals of hydrate [Cu(HL)Cl]•H₂O (3) were grown for the X-ray diffraction study, which showed that the crystal structure of 3 consists of the molecules of a mononuclear complex [Cu(HL)Cl] containing tridentate chelating ligand HL—, and water molecules. Coordination polyhedron ClNO₂ is a distorted tetrahedron. Intermolecular con- tacts in the structure 3 lead to the formation of supramolecular chains, parallel to the axis -6h. Compounds 1 and 2 were studied by ESR and IR spectroscopy.     

Origin of the axial-alkyl preference of (R)-α-phellandrene and related compounds investigated by high-level ab initio MO calculations. Importance of the CH/π hydrogen bond

Ab initio MO calculations were carried out, at the MP2/6-311++G(d,p)//MP2/6-311G(d,p) level, to investigate the Gibbs energy of conformational isomers of (R)-α-phellandrene and related 5-alkyl-1,3-cyclohexadienes. It has been found that the conformer bearing the 5-alkyl group in axial orientation is more stable than the equatorial congener. The result is consistent with experimental evidence that the axial-isopropyl conformer prevails in the conformational equilibrium of α-phellandrene. The reason for the stability of the folded conformer has been sought in the context of the CH/π hydrogen bond. A number of short non-bond distances have been disclosed in the axial conformers, between CHs in the 5-alkyl group and sp²-carbons of the cyclohexadiene ring. We suggest that the stability of the folded conformation often observed in conjugated diene compounds of natural origin, such as α-phellandrene and levopimaric acid, is attributed to an attractive molecular force, the CH/π hydrogen bond.     

Study of the protonation (methylation) position and tautomeric structure of thiopyrimidine derivatives by 2D <Superscript>1</Superscript>H—<Superscript>15</Superscript>H NMR HSQC/HMBC. Experimental approach and theoretical modeling

Two-dimensional ₁H—₁₅N NMR HSQC/HMBC experiments enable the unambiguous determination of the protonation (methylation) position and tautomeric structure of nitrogen-containing heterocycles. In investigated thiopyrimidines protonation (or methylation) occurs at the N(1) atom of the pyrimidine ring. The tautomeric structures of these compounds were established based on the analysis of ₁H—₁₅N NMR spectra. Ab initio calculations of chemical shifts (GIAO B3LYP/6-31G(d)//HF/6-31G) are in full agreement with experimental values. The stability of various protonated (methylated) and tautomeric species is explained in terms of a thermodynamic approach.     

The conformation of alkyl cyclohexanones and terpenic ketones. Interpretation for the ‘alkylketone effect’ based on the CH/π(CO) hydrogen bond

Ab initio MO calculations were carried out, at the MP2/6-311++G(d,p)//MP2/6-311G(d,p) level, to investigate the Gibbs free energy of the conformational isomers of 2-alkyl, 3-alkyl, and 4-alkyl cyclohexanones. The calculation gave results consistent with the general trend experimentally found. The genesis of stabilization of the axial conformers in 2- and 3-alkyl cyclohexanones, as compared to the structurally corresponding cyclohexane derivatives, was sought in the context of the attractive CH/π(CO) hydrogen bond. In support of this hypothesis, short nonbonded distances have been noted between CHs in the alkyl group and the carbonyl carbon in the relevant axial conformers. Calculations were also carried out to study the conformational energies of several terpenic ketones. For isomenthone, more than a half molecular fraction (ca. 55%) has been suggested to be in the isopropyl-axial conformation, while for isocarvomenthone ca. 77% has been suggested to be in the axial-isopropyl conformation; this is consistent with bibliographic experimental data. A crystallographic database search has provided results compatible with this conclusion. We suggest that the relative stability of the axial alkyl substituent, often observed in terpenic and steroidal ketones is rationalized in terms of an attractive molecular force, the CH/π(CO) hydrogen bond.     

Elimination of nitrile from (E)-2,4,6-trinitrobenzaldehyde O-pivaloyloxime promoted by R<Subscript>2</Subscript>NH in MeCN. Effect of β-aryl group on the nitrile-forming transition-state

Nitrile-forming eliminations from (E)-2,4,6-(NO₂)₃C₆H₂CH=NOC(O)(CH₃)₃ promoted by R₂NH in MeCN have been studied kinetically. The reactions are second-order and exhibit substantial Hammett ρ and Brönsted β values. The k ₂ value for elimination from (E)-2,4,6-trinitrobenzaldehyde O-pivaloyloxime promoted by i-Pr₂NH in MeCN falls on a single line in the Hammett plot for different β-aryl substituents, which have been shown to react by the E2 mechanism. This result indicated that the reaction mechanism is not changed by the introduction of the 2,4,6-trinitro substituents, and that the elimination reactions from (E)-benzaldehyde O-pivaloyloximes series proceed by the common E2 mechanism.     

Reaction of Moore's ketene (tert-butylcyanoketene) with 1,3-cyclopentadiene and 1,3-cyclohexadiene. Is periselectivity controlled by the dynamic of trajectories at the bifurcation point?

The cycloaddition reaction of tert-butylcyanoketene (TBCK, Moore's ketene) with 1,3-cyclopentadiene yields the [2+2] product, namely cyclobutanone 9. TBCK and 1,3-cyclohexadiene provide the cyclobutanone 10 and some of the ether 11. Both reactions yielding the cyclobutanones (9 and 10, respectively) are reversible. Cyclobutanone 10 is converted thermally and irreversibly into the bicyclic ether 11 via a [3,3] sigmatropic rearrangement (oxo-Cope). The X-ray single crystal data for the ether 11 confirms that the CN and the ether oxygen are in a trans configuration. Data provided by density functional calculations at B3LYP/6-311++G(d,p) level mirror the X-ray data.Furthermore, the relative thermodynamic stabilities (ΔG calculated at 273 °C, 1 atm) of the most relevant isomers of 10 at mPWB1K/6-31+G(d,p) level of theory is provided. Details of the transition states that: (i) leads to cyclobutanone 10 from TBCK and 1,3-cyclohexadiene, and (ii) the oxo-Cope rearrangement of cyclobutanone 10 to produce ether 11 are provided.     

Apparent molar volumes and apparent molar heat capacities of aqueous d-lactose · H2O at temperatures from (278.15 to 393.15) K and at the pressure 0.35 MPa

Apparent molar volumes V_φ and apparent molar heat capacities C_p,φ were determined for aqueous solutions of d-lactose · H₂O at molalities (0.01 to 0.34) mol · kg⁻¹ at temperatures (278.15 to 393.15) K, and at the pressure 0.35 MPa. Our V_φ values were calculated from densities obtained using a vibrating tube densimeter, and our C_p,φ values were obtained using a twin fixed-cell, power-compensation, differential-output, temperature-scanning calorimeter. Our results for d-lactose(aq) and for d-lactcose · H₂O were fitted to functions of m and T and compared with the literature results for aqueous d-glucose and d-galactose solutions. Infinite dilution partial molar volumes V₂^∘ and heat capacities C_p,2^∘ are given over the range of temperatures.