Hsiao-Fen Wang

Dual Bioactivities of Essential Oil Extracted from the Leaves of Artemisia argyi as an Antimelanogenic versus Antioxidant Agent and Chemical Composition Analysis by GC/MS

The study was aimed at investigating the antimelanogenic and antioxidant properties of essential oil when extracted from the leaves of Artemisia argyi, then analyzing the chemical composition of the essential oil. The inhibitory effect of the essential oil on melanogenesis was evaluated by a mushroom tyrosinase activity assay and B16F10 melanoma cell model. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis, and the volatile chemical composition of the essential oil was analyzed with gas chromatography-mass spectrometry (GC/MS). The results revealed that the essential oil significantly inhibits mushroom tyrosinase activity (IC50 = 19.16 mg/mL), down-regulates B16F10 intracellular tyrosinase activity and decreases the amount of melanin content in a dose-dependent pattern. Furthermore, the essential oil significantly scavenged 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzthiazoline- 6-sulphonic acid) ABTS radicals, showed an apparent reduction power as compared with metal-ion chelating activities. The chemicals constituents in the essential oil are ether (23.66%), alcohols (16.72%), sesquiterpenes (15.21%), esters (11.78%), monoterpenes (11.63%), ketones (6.09%), aromatic compounds (5.01%), and account for a 90.10% analysis of its chemical composition. It is predicted that eucalyptol and the other constituents, except for alcohols, in the essential oil may contribute to its antioxidant activities. The results indicated that essential oil extracted from A. argyi leaves decreased melanin production in B16F10 cells and showed potent antioxidant activity. The essential oil can thereby be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products.

The Dual Antimelanogenic and Antioxidant Activities of the Essential Oil Extracted from the Leaves of Acorus macrospadiceus (Yamamoto) F. N. Wei et Y. K. Li

The antimelanogenic and antioxidant activities of the essential oil extracted from the leaves of Acorus macrospadiceus (Yamamoto) F. N. Wei et Y. K. Li have never been explored. The essential oil effectively inhibited mushroom tyrosinase activity (EC50 = 1.57 mg/mL) and B16F10 tyrosinase activity (IC50 = 1.01 mg/mL), decreased the melanin content (EC50 = 1.04 mg/mL), and depleted the cellular level of the reactive oxygen species (ROS) (EC50 = 1.87 mg/mL). The essential oil effectively scavenged 2,2-diphenyl-1-picryl-hydrazyl (DPPH) (EC50 = 0.121 mg/mL) and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) ABTS+ radicals (EC50 = 0.122 mg/mL). It also exhibited an apparent reducing power (EC50 = 0.021 mg/mL) and metal-ion chelating activity (EC50 = 0.029 mg/mL). The chemical constituents of the essential oil are ethers (55.73%), ketones (19.57%), monoterpenes (7.82%), alcohols (3.85%), esters (3.77%), sesquiterpenes (3.72%), and aromatic compounds (2.85%). The results confirm that A. macrospadiceus essential oil is a natural antioxidant and inhibitor of melanogenesis.

Dicarbonyl­chlorido(phen­oxy­thio­carbonyl-κ2C,S)bis­(triphenyl­phosphane-κP)molybdenum(II)

In the title complex, [Mo(C7H5OS)Cl(C18H15P)2(CO)2], the geometry around the metal atom is a capped octahedron. The phenoxythiocarbonyl ligand coordinates the MoII atom through the C and S atoms. A one-dimensional structure is formed by π–π intermolecular interactions and a supramolecular aggregation is determined by intermolecular C—H⋯O, C—H⋯Cl, C—H⋯π(arene) hydrogen bonds and CO⋯π(arene) interactions [O⋯centroid distances = 3.485 (4) and 3.722 (3) Å].

Bis(carbonyl-κC)(N,N-dimethyl­thio­carbamoyl-κ2C,S)(pyridine-2-thiol­ato-κ2N,S)(triphenyl­phosphine-κP)molybdenum(II)

There are two independent molecules with similar configurations in the title complex, [Mo(C3H6NS)(C5H4NS)(C18H15P)(CO)2]. The geometry around the metal atom is that of a capped octahedron. The thiocabamoyl and pyridine-2-thiolate ligands coordinate to the molybdenum metal center through the C and S atoms, and N and S atoms, respectively. NMR, IR and MS analyses are in agreement with the structure of the title compound.

trans-Bromido(pyrimidinyl-κC2)bis­(triphenyl­phosphane-κP)palladium(II)

There are two independent molecules with similar configurations in the asymmetric unit of the title complex, [Pd(C4H3N2)I(C18H15P)2]. In each molecule, the geometry around the Pd atom is distorted square-planar, with the Pd atom displaced by 0.0549 (12) and 0.0734 (13) Å from the least-squares plane of the I—P—P—C atoms. The PPh3 ligands are in trans positions, with P—Pd—P angles of 173.12 (4) and 170.29 (4)°, while the pyrazinyl ligands and I atoms, also trans to each other, form C—Pd—I angles of 179.38 (12) and 178.44 (12)°. In the crystal, C—H⋯π interactions occur, resulting in a three-dimensional supramolecular architecture.

[(Pyrrolidin-1-yl)carbothio­ylsulfan­yl]methyl pyrrolidine-1-carbodithio­ate

The title compound, C11H18N2S4, was unexpectedly obtained during studies on the reactivity of the complex tris(acac-κ2 O,O′)gallium(III) (acac is acetylacetonate) with C4H8NCS2H in dichloromethane. The title compound shows disordered two pyrrolidine rings with major and minor occupancies of 0.546 (4) and 0.454 (4). Two (pyrrolidin-1-yl)carbothioylsulfanyl units are linked together through a methylene C atom and weak C—H⋯S interactions are found.

trans-Bromido(pyrimidinyl-κC)bis-(triphenyl-phosphane-κP)palladium(II).

In the title complex, [PdBr(C4H3N2)(C18H15P)2], the geometry around the PdII atom is distorted square-planar with the PdII atom displaced by 0.0150 (5) Å from the least-squares BrP2C plane. Two PPh3 ligands are in trans positions [P—Pd—P = 176.743 (17)°], while the pyrimidinyl ligand and Br atom are trans to one another [C—Pd—Br = 176.56 (5)°]. Structural parameters from NMR, IR and mass spectra are in agreement with the crystal structure of the title compound.