Investigation of symptoms of hand skin changes with aging in Korean women and development of a new standard grading scale for hand aging.

Background: Skin aging, particularly facial skin, has been actively studied. However, hand skin research is limited.

Methods: Aging symptoms of 100 hands of Korean women aged from 20s to 60s were measured by noninvasive and bioengineering methods.

Effects of resveratrol, oxyresveratrol, and their acetylated derivatives on cellular melanogenesis.

Resveratrol and oxyresveratrol are naturally occurring phenolic compounds with various bioactivities, but their uses in cosmetics have been partly limited by their chemical instabilities. This study was performed to examine the anti-melanogenic effects of the acetylated derivatives from resveratrol and oxyresveratrol. Resveratrol and oxyresveratrol were chemically modified to triacetyl resveratrol and tetraacetyl oxyresveratrol, respectively.

Analysis of the temporal change in biophysical parameters after fractional laser treatments using reflectance confocal microscopy.

Background: Fractional photothermolysis is a popular treatment option for photorejuvenation. Previous literature studies have demonstrated the clinical effectiveness of fractional photothermolysis on cutaneous photoaging; however, the associated changes in biophysical properties of the skin following fractional photothermolysis have not been fully elucidated. This study was conducted to investigate the temporal changes in biophysical parameters after fractional laser treatment on Asian skin.

Use of non-melanocytic HEK293 cells stably expressing human tyrosinase for the screening of anti-melanogenic agents.

Tyrosinase (TYR) from mushrooms has been inappropriately used in the screening assay for hypopigmenting agents even though its biochemical properties are different from those of human TYR. Cell-free extracts of human epidermal melanocyes (HEMs) could be another choice for the assay, but HEMs grow too slowly to get a sufficient amount of cell-free extracts. In the present study, human embryonic kidney (HEK) 293 cells were transfected with a human TYR construct to establish a cell line that grows rapidly and expresses human TYR constitutively.

Comparison of the antimelanogenic effects of p-coumaric acid and its methyl ester and their skin permeabilities.

Background: p-Coumaric acid (PCA) inhibits human tyrosinase (TYR) activity and melanin synthesis in human epidermal melanocytes.

Objective: The purpose of the current study was to examine the potential of PCA and its hydrophobic derivative, methyl p-coumarate (MPC), as hypopigmenting agents for topical use.

Methods: PCA and MPC were comparatively tested against in vitro human TYR enzyme activity and cellular melanin synthesis in human epidermal melanocytes.

p-coumaric acid not only inhibits human tyrosinase activity in vitro but also melanogenesis in cells exposed to UVB.

Tyrosinase (TYR) catalyzes rate-limiting steps of melanogenesis and thus its inhibitors are potentially useful as hypopigmenting agents. Recently, p-coumaric acid (p-CA) has been suggested to interfere with the pro-melanogenic actions of tyrosine due to its structural similarity with tyrosine (An SM et al., Br J Dermatol 2008.

Inhibition of melanogenesis by tyrosinase siRNA in human melanocytes.

Tyrosinase (TYR) plays a critical role in cellular melanogenesis and, thus, has been the major target of pharmacological approaches for the control of skin pigmentation. This study examined an alternative molecular approach using TYR-small interfering RNA (siRNA) to control melanogenesis in the human melanocytes. Both the mRNA and protein levels of TYR were significantly lowered by TYR-siRNA treatment, whereas TYR-related protein 1 and TYR-related protein 2 displayed no such changes.

Oenothera laciniata inhibits lipopolysaccharide induced production of nitric oxide, prostaglandin E2, and proinflammatory cytokines in RAW264.7 macrophages.

We elucidated the pharmacological and biological effects of Oenothera laciniata extracts on the production of inflammatory mediators in macrophages. The CH(2)Cl(2) fraction of O. laciniata extract effectively inhibited LPS-induced NO, PGE(2), and proinflammatory cytokine production in RAW264.

Effect of Camellia japonica oil on human type I procollagen production and skin barrier function.

Type I collagen is the primary component of the skin dermis. Both the quantity and quality of extracellular collagen are primarily related to skin ageing. In this study, we investigated the possibility that Camellia japonica oil (CJ oil) may be introduced as an anit-wrinkle agent.