BackgroundEssential oils extracted from aromatic plants exhibit important biological activities and have become increasingly important for scientific research. The essential oil extracted from Cinnamomum cassia Presl (CC-EO) has various functional properties, however, little information is available regarding the tyrosinase inhibitory activity. Therefore, the objectives of this study were to investigate the chemical composition and tyrosinase inhibitory activity of the CC-EO.Resultscis-2-methoxycinnamic acid (43.06%) and cinnamaldehyde (42.37%) were found to be the two major components of the CC-EO identified by gas chromatography–mass spectrometry (GC-MS). The inhibitory activities of CC-EO and its major constituents were further evaluated against mushroom tyrosinase. The results showed that CC-EO and cinnamaldehyde exhibited anti-tyrosinase activities with IC50 values of 6.16 ± 0.04 mg/mL and 4.04 ± 0.08 mg/mL, respectively. However, cis-2-methoxycinnamic acid did not show any anti-tyrosinase activity. The inhibition kinetics were analyzed by Lineweaver-Burk plots and second replots, which revealed that CC-EO and cinnamaldehyde were mixed-type inhibitors. The inhibition constants (Ki) for CC-EO and cinnamaldehyde were calculated to be 4.71 ± 0.09 mg/mL and 2.38 ± 0.09 mg/mL, respectively.ConclusionThese results demonstrate that CC-EO and its major component, cinnamaldehyde, possess potent anti-tyrosinase activities and may be a good source for skin-whitening agents.Electronic supplementary materialThe online version of this article (doi:10.1186/1999-3110-54-10) contains supplementary material, which is available to authorized users.

Achillea millefolium L. is a member of the Asteraceae family and has been used in folk medicine in many countries. In this study, 19 compounds in A. millefolium essential oil (AM-EO) have been identified; the major components are artemisia ketone (14.92%), camphor (11.64%), linalyl acetate (11.51%) and 1,8-cineole (10.15%). AM-EO can suppress the inflammatory responses of lipopolysaccharides (LPS)-stimulated RAW 264.7 macrophages, including decreased levels of cellular nitric oxide (NO) and superoxide anion production, lipid peroxidation and glutathione (GSH) concentration. This antioxidant activity is not a result of increased superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, but rather occurs as a result of the down-regulation of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and heme oxygenase-1 (HO-1) expression, thus reducing the inflammatory response. Therefore, AM-EO can be utilized in many applications, including the treatment of inflammatory diseases in the future.

A 24-membered macrocyclic polyamine based on the propylene-1,3-diamine unit that was able to form polyprotonated, highly charged species in the neutral pH region was selected to act as an anion complexone. It was synthesized and incorporated in a fused-silica capillary for the electrophoretic separation of inorganic and organic anions. This complexing agent can selectively modulate the mobility of anions by forming anion complexes with varying degrees of stability. Parameters which influence capillary electrophoretic separations such as applied voltage, choice of electrolyte anion, electrolyte pH and electrolyte concentration were investigated. A mixture of thiosulfate, chloride, sulfate, selenate, perchlorate, tungstate, carbonate and selenite could be separated in 5 mm sodium chromate at pH 10.0 within 13 min. A mixture of bromide, oxalate, malate, citrate, tartrate, maleate, succinate, acetate, lactate, butyrate, p-hydroxybenzoate, salicylate and octanesulfonate could be separated in 10 mm phthalate at pH 5.0 within 11 mins. Under the same conditions, even geometric isomers or mixtures of polycarboxylates and polyphosphates, such as ATP and ADP, could be well separated. The experimental results indicated that incorporating the chelating functional group in the inner wall of the capillary markedly enhances the selectivity of the system.

Yerba mate tea is known as one of the most popular nonalcoholic beverages favoured by South Americans due to its nutrition facts and medicinal properties. The processing of yerba mate tea is found to affect the properties of its final forms. This study presents an investigation into the effects of water sources on the dissolution of yerba mate extract powders. Comparisons were conducted between yerba mate teas prepared by dissolving yerba mate extract powders into tap water and deionized water. Topics to be explored in this work are the major compositions and antioxidant activities, including total phenol content, reducing power, DPPH scavenging activity, and ABTS+• scavenging capacity. It is indicated that there is little difference for antioxidant activities and major constituents of yerba mate teas between both water sources. However, a deeper color is seen in the tap water case, resulting from the reaction between tannic acid and ions. This research finding can be treated as a way to benefit the yerba mate tea processing for applications.

Due to the severe toxic effects of mercury (Hg) and its derivatives, they are strictly prohibited to be used as cosmetics ingredients. Nevertheless, unknown quantities of Hg are formulated in consumer cosmetic products. We demonstrate a disposable screen-printed electrode modified with 1,5-dibromopentane partially (7%) cross-linked poly(4-vinylpyridine) (SPE/pcPVP) system for the detection of hidden concentrations of mercury, [Hg] within cosmetics goods by anodic stripping analysis in 0.01 M KCl + 0.02 M H2SO4 (1M = 1mol dm−3) solution. The Hg2+ ion in a chloride medium transforms to [HgCl4]2−, which then selectively preconcentrate and electro-deposite as metallic mercury, Hg0 on the cationic SPE/pcPVP (PVP exist as PVP+ in pH < 5). Under optimal conditions, the calibration graph is linear in the window of 25–150 ppb, with a detection limit (S/N = 3) and regression coefficient of 3.21 ppb and 0.9909 respectively for the SPE/pcPVP. Real sample assay results for the three skin-lightening agents are evidence of the precise existence of prohibited Hg (compared with ICP-MS measurements) in the products. This article further cautions the public of Hg toxicity in cosmetics. Since the approach is low cost and disposable, it is highly suitable for unskilled electrochemists.