Melanin-Decolorizing Activity of Antioxidant Enzymes, Glutathione Peroxidase, Thiol Peroxidase, and Catalase.

Melanin is the most important factor to determine skin color. Many research efforts are being undertaken to decompose the already-produced melanin compounds in skin for beauty. This research investigated the effects on reducing melanin color of the three antioxidant enzymes, Glutathione peroxidase (GPX), Thiol peroxidase (TPX), and Catalase, in lysosomal fraction. Melanin solution was treated with the enzymes and hydrogen peroxide, then reacted for 48 h. GPX and TPX decolorized melanin, and between them, GPX was more efficient, but Catalase was not effective. GPX also inhibited the production of melanin in B16F10 melanoma cells. GPX, which is present in almost all microorganisms, plays an important role in the cellular defense mechanism by reactive oxygen species. In addition, it was not cytotoxic, but was significantly effective in decolorizing melanin color. Therefore, in the biological and microbiological field, its possibility of utilization in skin whitening cosmetic is high.

Characterization of Ginkgo biloba Leaf Flavonoids as Neuroexocytosis Regulators.

Ginkgo biloba leaf (GBL) is known as a potential source of bioactive flavonoids, such as quercetin, arresting the neuronal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-zippering. Here, the GBL flavonoids were isolated in two different manners and then examined for their bioactivity, physicochemical stability, and biocompatibility. The majority of flavonoids in the non-hydrolyzed and acidolyzed isolates, termed non-hydrolyzed isolate (NI) and acidolyzed isolate (AI) hereafter, were rich in flavonol glycosides and aglycones, respectively. Glycosidic/aglyconic quercetin and kaempferol were abundant in both NI and AI, whereas a little of apigenin, luteolin, and isorhamnetin were found in AI. NI was more thermostable in all pH ranges than quercetin, kaempferol, and AI. NI and AI both inhibited neurotransmitter release from differentiated neuronal PC-12 cells. NI and AI showed 1/2-1/3 lower EC50/CC50 values than quercetin and kaempferol. The NI and AI exhibited no toxicity assessed by the tests on chorioallantoic membranes of hen's eggs, removing toxicological concerns of irritation potential. Moreover, GBL isolates, particularly AI, showed antioxidant and anti-inflammatory activities in the use below the CC50 levels. Taken together, these results suggest that GBL isolates that are rich in antioxidant flavonoids are effective anti-neuroexocytotic agents with high stability and low toxicity.

The skin-permeation-enhancing effect of phosphatidylcholine: caffeine as a model active ingredient.

Phospholipids or liposomes are recognized to have skin permeation enhancing ability, although their mechanisms are still controversial. The aim of this study was to establish a method of increasing the skin permeation of active ingredients, using phosphatidylcholine as a permeation enhancer. Caffeine was used as a model active ingredient and in vitro skin penetration experiments were performed using Franz-type diffusion cells to determine the amount of absorbed caffeine. Lipid vesicles were prepared by the microfluidization process. The encapsulation efficiency of caffeine was found to be very low due to the instability of the liposome structure and the water solubility of caffeine. However, the amount of absorbed caffeine was nearly independent of the encapsulation efficiency and the vesicle size, but increased with the increase of phosphatidylcholine concentration. These results indicated that phosphatidylcholine could act as a penetration enhancer, irrespective of its presence in vesicular form or solubilized form.