Clinical studies have identified that an excessive exposure of UV light can cause oxidative stress (OS) and tyrosinase enzyme over-expression, which are associated with multiple diseases including atherosclerosis, cancers, diabetics, rheumatoid arthritis. In this study, we investigated the impact of grape seed proanthocyanidin (GSPE) on regulating OS and tyrosinase activity in human epidermal melanocytes. This study revealed that GSPE did not affect cell viability and protected cells from UV induced damage in a dose-dependent manner. 5-(-6)-Carboxy-2,7-di-chlorodihydro-fluorescein diacetate staining (i.e., a fluorescence staining for intracellular (OS)) indicated that GSPE reduced OS level caused by UV exposure. A similar trend was also confirmed by flow cytometry analysis, where GSPE down-regulated OS level. Tyrosinase analysis showed that GSPE treatment decreased tyrosinase activity. Taken all data together, GSPE may restore the cellular damage caused by excessive UV-exposure and promote skin health by reducing tyrosine generation. Clinically, GSPE could be potentially utilized for improving skin health against excessive UV exposure.

A dinuclear complex [Dy(m-MBA)3phen]2-H2O was prepared by the reaction of DyCl3-6H2O, m-methylbenzoic acid and 1,10-phenanthroline in a 1:3:1 molar ratio, where m-MBA = m-methylbenzoate and phen = 1,10-phenanthroline. The complex was structurally characterized by single crystal X-ray diffraction, elemental analysis, UV and IR spectroscopy, molar conductance and TG-DTG techniques. It crystallizes in the monoclinic space group Cc with a =15.962(16), b = 18.505(18), c = 22.547(2) Ǻ; a = 90 °, β = 97.9820(10) °, y = 90°; z = 4. The unit cell contains a dinuclear molecule of the title compound. Each Dy(III) ion is eight-coordinated to one 1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups. The carboxylate groups are bonded to the dysprosium ions in two modes: chelating bidentate and bridging bidentate. The thermal decomposition process of [Dy(m-MBA)3phen]2-H2O has been followed by thermal analysis.

O complexo [Sm(oClBA)3phen]2 (oClBA= o-clorobenzoato; phen= 1,10-fenantrolina) foi preparado pela reação de SmCl3·6H2O com ácido o-clorobenzóico e 1,10-fenantrolina. O complexo foi caracterizado por um estudo de difração de raios-X, análise elementar, espectroscopia no infravermelho e técnicas TG-DTG. O cristal é triclínico, grupo espacial P I com a = 13,157(3) Å, b = 14,139(4) Å, c = 17,397(4) Å, alfa = 83,755(3)º, beta = 84,064(3)º, gama = 73,434(3)º, Z=2, Dc=1,722 Mg/m³, F(000)=1572. Contém duas unidades cristalograficamente distintas de Sm(o-ClC6H4COO)3(C12H 8N2), formando dois tipos de moléculas binucleares. Cada Sm3+ encontra-se coordenado a dois átomos de oxigênio de um grupo carboxilato bidentado quelante, cinco átomos de oxigênio de dois grupos carboxilatos bidentados ligados em ponte e de três grupos carboxilatos tridentados quelantes e ligados em ponte, e a dois átomos de nitrogênio de uma molécula de 1,10-fenantrolina, completando uma geometria monoencampuzada antiprismática quadrada. A decomposição térmica deste composto foi estudada por técnicas TG-DTG, e os parâmetros cinéticos da primeira etapa da decomposição foram determinados pelos métodos de Kissinger e Ozawa-Doyle. A equação de meia vida após 10% de perda de peso, lntau= 26,8166+20319,94/T, foi deduzida por análise termogravimétrica da isoterma.

The title complex [Sm(oClBA)3phen]2 (oClBA= o-chlorobenzoate; phen= 1,10-phenanthroline) was prepared by the reaction of SmCl3·6H2O, o-chlorobenzoic acid and 1,10-phenanthroline. The complex was characterized by single crystal X-ray diffraction, elemental analysis, IR spectra and TG-DTG techniques. The results show that the crystal is triclinic, space group P I with a = 13.157(3) Å, b = 14.139(4) Å, c = 17.397(4) Å, alpha = 83.755(3)º, beta = 84.064(3)º, gamma =73.434(3)º, Z=2, Dc=1.722 Mg/m³, F(000)=1572. The crystal contains two crystallographically distinct Sm(o-ClC6H4COO)3(C12H 8N2) units, forming two types of binuclear molecule. Each Sm3+ is coordinated to two O atoms of one bidentate chelating carboxylate group, five O atoms of two bidentate bridging and two tridentate chelating-bridging carboxylate groups, and two N atoms of one 1,10-phenanthroline molecule to complete a distorted mono-capped square antiprism geometry. Its thermal decomposition mechanism was determined by TG-DTG techniques, and kinetic parameters have been studied on the first-step decomposition of [Sm(oClBA)3phen]2 by means of Kissinger's method and Ozawa-Doyle's method. The lifetime equation at weight-loss of 10% was deduced as lntau= 26.8166+20319.94/T by isothermal thermogravimetric analysis.