Takamasa Atsumi

Hamamelitannin as a new potent active oxygen scavenger

Abstract The active oxygen scavenging activities of hamamelitannin (2′, 5-di- O -galloylhamamelose), which is a major constituent of Hamamelis virginiana , gallic acid, which is thought to be the active moiety of hamamelitannin, and propyl gallate which is a well-known antioxidant, were evaluated. In superoxide anion scavenging, the IC 50 values, which represent the concentration giving 50% inhibition of active oxygens generated, of hamamelitannin (1.31±0.06 μM), gallic acid (1.01±0.03 μM) and propyl gallate (1.41±0.01 μM) were higher than that of ascorbic acid (23.31±2.23 μM). In hydroxyl radical scavenging, hamamelitannin gave the lowest IC 50 value (5.46±0.04 μM) among the compounds tested; the values of gallic acid and propyl gallate were 78.04±11.23 and 86.46±2.31 μM, respectively. In singlet oxygen scavenging, the IC 50 values of hamamelitannin, gallic acid and propyl gallate were 45.51±2.00, 69.81±4.66 and 66.66±2.46 μM, respectively. Hamamelitannin was also found to have antioxidative and scavenging activities against organic radicals like DPPH (1, 1-diphenyl-2-picrylhydrazyl). In a cell culture system, the protective activities of hamamelitannin on cell damage induced by active oxygens, such as superoxide anion radicals, hamamelitannin on cell damage induced by active oxygens, such as superoxide anion radicals, hydroxyl radicals and singlet oxygens, were also evaluated. Against superoxide anion radicals hamamelitannin and propyl gallate protected the cells at over 50 μM, while the protective activity of gallic acid was observed at 500 μM. In contrast, against hydroxyl radicals, hamamelitannin showed protective activity at over 500 μM, while gallic acid and propyl gallate protected at 50 μM. Against singlet oxygens, hamamelitannin indicated survival of 80.6±1.5% at 100 μM, in which the survival of the control was 60.4±6.2%. Gallic acid and propyl gallate showed survivals of 98.6±7.3 and 85.2±4.9% at 500 μM, respectively. DMPO (5,5-dimethyl-1-pyrroline- N -oxide) and PBN (α-phenyl- N-t -butylnitrone) typical ESR spin-trap reagents, were found to protect against cell damage induced by superoxide anion and hydroxyl radicals.

The simple measuring method of water evaporation rate from the skin using anhydrous cobalt chloride paper

In considering the effectiveness of cosmetics, the moisturizing effect on the skin is most important.This consists of two components, one being the occlusivity which supress water evaportion, and the other is water holding capacity. The new method for measuring the water evaporation rate has been developed by us. This method is made up by anhydrous cobalt chloride paper and high-speed spectrophotometer, Anhydrous cobalt chloride changes color from blue to pink when it absorbs water. The change in the reflectance was measured with a high-speed spectrophotometer. The detail of this method and examples measured were reported.

Behavior of Methylparaben in Emulsified Cosmetics Containing Powder

The emulsified cosmetics containing powder are composed of such complex systems that their antimicrobial activity often becomes a problem. First, we investigated the behavior of methylparaben (MP) in these systems to estimate the concentration of the active form of parabens.Adsorption of MP by powder was expressed as a linear function of the initial concentration of MP (Co) when the powder content was constant.In the system containing powder and surfactant, the concentration of free MP in the aqueous phase (C3) was 62-65% of Co.In a model emulsion containing powder, the corresponding value (C5) was 20-27% of Co. In this system, the free MP in the aqueous phase before the powder addition was considered to be mainly adsorbed by powder.

A quantitative analysis for the skin surface lipids by Infrared spectrophotometry

The quantity of skin surface lipids eluted with carbon tetrachloride was accurately determined by infrared spectrophotometry, which was obtained from only one square centimeter of skin surface. A crystalline cell (Light pass length=10mm) was used for its measurement. The linear relation ships was formed between skin surface lipids weight and its maximum absorbance of the methylene strech band at 2,930cm-1.