Development of chemometric-assisted supercritical fluid extraction of effective and natural tyrosinase inhibitor from Syzygium aqueum leaves.

Tyrosinase is a key enzyme in enzymatic browning, causing quality losses in food through the oxidation process. Thus, the discovery of an effective and natural tyrosinase inhibitor via green technology is of great interest to the global food market due to food security and climate change issues. In this study, Syzygium aqueum (S.

Correction: White light employing luminescent engineered large (mega) Stokes shift molecules: a review.

[This corrects the article DOI: 10.1039/D1RA00129A.].

Unraveling the surface properties of PMMA/azobenzene blends as coating films with photoreversible surface polarity.

Various reports demonstrated that azobenzene derivatives are the chromophore of choice in photoresponsive surfaces showing reversible surface polarity. Hitherto the surface study of coating films based on polymer/azobenzene blends using contact angle measurements remained unexplored. To provide insight into the surface polarity of polymer/dye blend films, poly(methyl methacrylate) (PMMA) blends containing photoresponsive 4-hydroxy-4'-methylazobenzene (AZO1) and 4,4'-dimethylazobenzene (AZO2) as coating films on clear glass substrates are investigated in this work.

White light employing luminescent engineered large (mega) Stokes shift molecules: a review.

Large (mega) Stokes shift molecules have shown great potential in white light emission for optoelectronic applications, such as flat panel display technology, light-emitting diodes, photosensitizers, molecular probes, cellular and bioimaging, and other applications. This review aims to summarize recent developments of white light generation that incorporate a large Stokes shift component, key approaches to designing large Stokes shift molecules, perspectives on future opportunities, and remaining challenges confronting this emerging research field. After a brief introduction of feasible pathways in generating white light, exemplifications of large Stokes shift molecules as white light candidates from organic and inorganic-based materials are illustrated.

Recent advances in halal food authentication: Challenges and strategies.

Increasing public awareness of food quality and safety has prompted a rapid increase in food authentication of halal food, which covers the production method, technical processing, identification of undeclared components, and species substitution in halal food products. This urges for extensive research into analytical methods to obtain accurate and reliable results for monitoring and controlling the authenticity of halal food. Nonetheless, authentication of halal food is often challenging because of the complex nature of food and the increasing number of food adulterants that cause detection difficulties.

Accelerated nucleophilic substitution reactions of dansyl chloride with aniline under ambient conditions via dual-tip reactive paper spray.

Paper spray ionization (PSI) mass spectrometry (MS) is an emerging tool for ambient reaction monitoring via microdroplet reaction acceleration. PSI-MS was used to accelerate and monitor the time course of the reaction of dansyl chloride with aniline, in acetonitrile, to produce dansyl aniline. Three distinct PSI arrangements were explored in this study representing alternative approaches for sample loading and interaction; conventional single tip as well as two novel setups, a dual-tip and a co-axial arrangement were designed so as to limit any on-paper interaction between reagents.

Furo[3,2-c]coumarin-derived Fe Selective Fluorescence Sensor: Synthesis, Fluorescence Study and Application to Water Analysis.

Furocoumarin (furo[3,2-c]coumarin) derivatives have been synthesized from single step, high yielding (82-92%) chemistry involving a 4-hydroxycoumarin 4 + 1 cycloaddition reaction. They are characterized by FTIR, H-NMR, and, for the first time, a comprehensive UV-Vis and fluorescence spectroscopy study has been carried out to determine if these compounds can serve as useful sensors. Based on the fluorescence data, the most promising furocoumarin derivative (2-(cyclohexylamino)-3-phenyl-4H-furo[3,2-c]chromen-4-one, FH), exhibits strong fluorescence (ФF = 0.

White Light Emission from a Simple Mixture of Fluorescent Organic Compounds.

Three fluorescent organic compounds-furocoumarin (FC), dansyl aniline (DA), and 7-hydroxycoumarin-3-carboxylic acid (CC)-are mixed to produce almost pure white light emission (WLE). This novel mixture is immobilised in silica aerogel and applied as a coating to a UV LED to demonstrate its applicability as a low-cost, organic coating for WLE via simultaneous emission. In ethanol solution and when immobilised in silica aerogel, the mixture exhibits a Commission Internationale d'Eclairage (CIE) chromaticity index of (0.

Reflexin A, a new indole alkaloid from induces apoptosis against colon cancer cells.

One new indole alkaloid, reflexin A (), and two known indoles, macusine B () and vinorine (), were isolated from the bark of . Their structures were elucidated by 1D and 2D NMR, UV, IR, and MS spectroscopic analyses. Compound displayed anticancer activity against HCT-116 colon cancer cells with an IC value of 30.

Antioxidant Properties and Gastroprotective Effects of 2-(Ethylthio)Benzohydrazones on Ethanol-Induced Acute Gastric Mucosal Lesions in Rats.

A series of new 2-(ethylthio)benzohydrazone derivatives (1-6) were prepared and characterised by IR, 1H NMR, and 13C NMR spectroscopy and mass spectrometry. The newly prepared compounds were screened for their in vitro antioxidant activities using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Among them, most powerful antioxidant, compound 1 has been selected in order to illustrate anti-ulcer effect on ethanol-induced gastric mucosal lesions in rats.

Solvent and pH Effects of Coumarin-Terminated Monolayer on Silver Particles.

A coumarin-terminated self-assembled monolayer on silver particles (C-SAM) from the reduction of silver ions in the presence of compound 3 was successfully prepared by utilizing phase transfer method, and analyzed by FTIR, SEM-EDS, UV-Visible and a particle sizer. The fluorescence behavior of coumarin termini was carried out in ethanol and chloroform with emission wavelength determined at 386 nm, suggesting an interaction between the carbonyl group and the solvent media. The dispersion was then investigated in acidic and basic conditions, showing a direct proportional correlation between the emission and the pH of the aqueous.

Crystal structure of a new monoclinic polymorph of N-(4-methyl-phen-yl)-3-nitro-pyridin-2-amine.

The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z' = 4) of the previously reported monoclinic (P21/c, with Z' = 2) form [Akhmad Aznan et al. (2010 ▶). Acta Cryst.

Crystal structures of 1,4-di-aza-bicyclo-[2.2.2]octan-1-ium 4-nitro-benzoate dihydrate and 1,4-di-aza-bicyclo-[2.2.2]octane-1,4-diium bis-(4-nitro-benzoate): the influence of solvent upon the stoichiometry of the formed salt.

The 1:1 co-crystallization of 1,4-di-aza-bicyclo-[2.2.2]octane (DABCO) with 4-nitro-benzoic acid in ethanol-water (3/1) gave the salt dihydrate C6H13N2 (+)·C7H4NO4 (-)·2H2O, (1), whereas from methanol, the salt C6H14N2 (2+)·2C7H4NO4 (-), (2), was isolated.

New thiosemicarbazides and 1,2,4-triazolethiones derived from 2-(ethylsulfanyl) benzohydrazide as potent antioxidants.

New thiosemicarbazide derivatives 2-6 were synthesised by reacting 2-(ethylsulfanyl)benzohydrazide with various aryl isothiocyanates. The cyclisation of compounds 2-6 under reflux conditions in a basic medium (aqueous NaOH, 4 N) yielded compounds 7-11 that contain a 1,2,4-triazole ring. All of the synthesised compounds were screened for their antioxidant activities.

1-Methyl-3-phenyl-imidazolidine-2-thione.

The asymmetric unit of the title cyclic thio-urea derivative, C10H12N2S, comprises two mol-ecules, each of which has a twist about the CH2-CH2 bond within the five-membered ring. The major difference between the independent mol-ecules is manifested in the relative orientations of the five- and six-membered rings [dihedral angles between the least-squares planes = 28.03 (11) and 41.

Synthesis and antibacterial evaluation of some novel imidazole and benzimidazole sulfonamides.

Several new substituted sulfonamide compounds were synthesized and their structures were confirmed by ¹H-NMR, ¹³C-NMR, FT-IR, and mass spectroscopy. The antibacterial activities of the synthesized compounds were screened against standard strains of six Gram positive and four Gram negative bacteria using the microbroth dilution assay. Most of the compounds studied showed promising activities against both types of bacteria.

Lumusidines A-D and villalstonidine F, macroline-macroline and macroline-pleiocarpamine bisindole alkaloids from Alstonia macrophylla.

Lumusidines A-D, bisindole alkaloids of the macroline-macroline type, and one of the macroline-pleiocarpamine type, villalstonidine F, were isolated from the stem-bark extract of Alstonia macrophylla (Apocynaceae). The structures and absolute configurations of these alkaloids were established using NMR, MS, and X-ray diffraction analyses.

N,N'-{[Ethane-1,2-diylbis(-oxy)]bis-(ethane-2,1-di-yl)}bis-(4-methyl-benzene-sulfonamide).

The asymmetric unit of the title compound, C(20)H(28)N(2)O(6)S(2), contains one half-mol-ecule, related to the other half by a twofold rotation axis. The two aromatic rings of the mol-ecule make a dihedral angle of 50.91 (7)°.

tert-Butyl 2-(1H-benzimidazol-1-yl)acetate.

In the title compound, C(13)H(16)N(2)O(2), the planes of the benzimidazole ring system and the acetate O-C=O fragment make a dihedral angle of 84.5 (3)°. In the crystal, mol-ecules are connected through C-H⋯N hydrogen bonds to form infinite chains in the [-110] direction.

tert-Butyl 2-(1H-imidazol-1-yl)acetate.

In the title compound, C(9)H(14)N(2)O(2), the imidazole ring and the acetate O-C=O plane make a dihedral angle of 80.54 (12)°. In the crystal, mol-ecules are connected via pairs of C-H⋯O hydrogen bonds, forming centrosymmetric dimers.

2-(2-Meth-oxy-phen-oxy)pyrazine.

A significant twist is observed in the title molecule, C(11)H(10)N(2)O(2), as seen in the dihedral angle between the pyrazine and benzene rings of 72.79 (8)°. The meth-oxy group is almost coplanar with the benzene ring to which it is attached [C-O-C-C torsion angle = 175.

4-Nitro-benzoic acid-N-(pyrimidin-2-yl)aniline (1/1).

Four independent mol-ecules comprise the asymmetric unit of the title co-crystal, C(10)H(9)N(3)·C(7)H(5)NO(4), two for each component. Small conformational differences are noted for the benzoic acid derivatives, notably in the twists of the carb-oxy-lic acid residue out of the plane of the benzene ring to which it is connected [torsion angles = 167.62 (17) and 174.

2-(Naphthalen-2-yl-oxy)-5-nitro-pyridine.

A nearly orthogonal relationship is found for the ring systems in the title compound, C(15)H(10)N(2)O(3), with the dihedral angle between the rings being 86.13 (11)°. The nitro group is approximately coplanar with the pyridine ring to which it is connected [the O-N-C-C torsion angle = -1.

4-Methyl-N-(3-methyl-phen-yl)pyridin-2-amine.

The title amine, C(13)H(14)N(2), is twisted with a dihedral angle between the rings of 60.07 (9)°. The amine N-H group and pyridine N atom are syn allowing for the formation of centrosymmetric eight-membered {⋯HNCN}(2) synthons via N-H⋯N hydrogen bonds.

2-(4-Methyl-phen-oxy)-5-nitro-pyridine.

The title mol-ecule, C(12)H(10)N(2)O(3), is twisted, the dihedral angle between the rings being 61.16 (13)°. The nitro group is approximately coplanar with the pyridine ring to which it is attached [O-N-C-C torsion angle = -178.