• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3301-3306
• /
• 2013

This paper aims to address the cellular toxicity of ultra-pure titanium dioxide ($TiO_2$) and zinc oxide (ZnO) nanoparticles (NPs) frequently employed in sunscreens as inorganic physical sun blockers to provide protection against adverse effects of ultraviolet (UV) radiation including UVB (290-320 nm) and UVA (320-400 nm). In consideration that the production and the use of inorganic NPs have aroused many concerns and controversies regarding their safety and toxicity and that microsized $TiO_2$ and ZnO have been increasingly replaced by $TiO_2$ and ZnO NPs (< 100 nm), it is very important to directly investigate a main problem related to the intrinsic/inherent toxicity of these NPs and/or their incompatibility with biological objects. In the present study, we took advantage of the laser-assisted method called laser ablation for generation of $TiO_2$ and ZnO NPs. NPs were prepared through a physical process of irradiating solid targets in liquid phase, enabling verification of the toxicity of ultra-pure NPs with nascent surfaces free from any contamination. Our results show that $TiO_2$ NPs are essentially non-poisonous and ZnO NPs are more toxic than $TiO_2$ NPs based on the cell viability assays.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.26 no.1
• /
• pp.41-58
• /
• 2000

Recently the harmfulness of W radiation is in creasing due to encironmental pollution. Environmental population may also play a role in global decrease of ozone layer, A major consequence of ozone depletion is increase in solar ultra violet radiation received at the earth's surface excessive exposure to W radiation cause a lot of problems in our skin. Plant extract that possess antioxidative activities has been reported to retard the oxidation process in product to which they have been added. Plant are alived under solar light. So it is expect the plants have so many protection mechanisms and UV absorbent ingredients against ultra violet radiation such as UVB, UVA. Plant extract which were flavonoids, alkaloids and others could be transformed into UV absorber by chemical modification. Therefore with the aim of finding alternative natural absorber that can safely be used in cosmetic, we have screened various extract for their UV absorbent effect. Thus, the cosmetic safety against human skin, antimicrobial effects and others could be improved by using the silicon.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.45 no.4
• /
• pp.415-422
• /
• 2019

Human epidermal stem cells(ESCs) residing in the basement membrane of the skin have an important role in maintenance of skin homeostasis of epidermal layer. Although, ESCs provide new cells to repair damaged tissue in response to tissue injury, subsets of stem cells remain in the quiescent state protected from differentiation and senescence for prolonged survivals. In this perspective, the stem cell niche, which is specific microenvironment composed of niche cells and an extracellular matrix(ECM), supplies the relevant signal to save stem cells from microenvironmental damages. The expression of stemness marker on the surface of ESCs contributes to the attachment on their ECM of the basement membrane, which lead to growth potential and apoptotic resistance against environmental stimuli. In this study, we observed that UV irradiation, a major factor of environmental stimuli, reduced the expression of α2, β1 and α6 integrin in ESCs. Rhus Semialata M extract(RSE) showed inhibitory effect on the UVB-induced reduction of integrin expression. Furthermore, RSE could upregulate the expression of Col-IV and Laminin, which contribute to the attachment of ESCs. These results indicated that RSE could be a potent ingredient for the protection of ESCs from UV irradiation by increasing the expression of integrin and substrate ECM components at their niche.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.6
• /
• pp.833-839
• /
• 2003

Quantitaties of flavonoids were determined by HPLC in three different ethanol extract (50, 70 and 95%, v/v) from Korean cherry. Antimicrobial activity of the ethanol extract and its solvent fraction (ethyl acetate and n-butanol fractions) against Staphylococcus aureus (ATCC 6538) and Staphylococcus epidermidis (ATCC 12228) was evaluated using MIC and disk test. Additionally, UV protective effect was also determined. The highest flavonoid quantity was found in 70% ethanol extract of Korean cherry. The quantities of quercitrin were 12.7 mg% and 2.1 mg% in ethyl acetate fraction and in buthanol fraction, respectively. In addition, the flavonoid in 70% (v/v) ethanol extract of Korean cherry included 14.9 mg% of quercitrin, 6.0 mg% of tannic acid and 5.2 mg% of catechin. Therefore, it was confirmed that main flavonoid of Korean cherry was quercitrin. For antimicrobial activity of ethanol extract of Korean cherry against Staphylococcus aureus (ATCC 6538) and Staphylococcus epidemidis (ATCC 12228), MIC and disk test using ethyl acetate fraction and butanol fraction were carried out. As a result, ethyl acetate fraction with higher quantity of flavonoid showed higher antimicrobial activity. Therefore, it was confirmed that the higher antimicrobial activity was brought about by flavonoid in Korean cherry. For UV protective effect of Korean cherry, ethanol extract showed the absorption zone of ultraviolet rays in 210∼380 nm including 290∼320 nm that is the wave length of UV-B harmful to the skin of human body. The pattern is the same as the absorption zone of 220∼300 nm in catechin and 210∼400 nm in quercitrin. Then, the functionalities of catechin and quercitrin were anticipated. It is expected that quercitrin in Korean cherry has the antimicrobial effect and UV protective effect related to the skin.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.31 no.4 s.54
• /
• pp.311-321
• /
• 2005

Tea (Camellia sinenis) is a popular beverage consumed worldwide. Since green tea, mainly consumed in Asia, has various biological activities, green tea components became one of the most favorite candidates as a functional materials for cosmetics and functional foods. The biological activities of green tea for skin cue have been ranged from protection of epidermal cells to the stimulation of extracellular matrix (ECM) biosynthesis. Green tea polyphenols (GTPs), which are active ingredients of green tea, possess anti-inflammatory, anti-carcinogenic and immune potentiation properties as well as antioxidant. They also modulate intracellular signal transduction pathways. GTPs decrease ultraviolet (UV)-induced oxidative stress, thus suppress mitogen-activated protein kinase (MAPK) pathway and apoptosis in keratinocytes. In addition, GTPs prevent the Induction of inflammatory mediators, such as cyclooxygenase-2 (COX-2), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) by tumor necrosis factor alpha $(TNF{\alpha})$ or chemical treatment in keratinocytes. GTPs treatment protects from chemical-or UV-induced skin tumor incidence in animal experiment. Besides, GTPs stimulate keratinocyte differentiation and proliferation of normal and aged epidermal cells, resectively, and suppress matrix metalloproteinases (MMPs) release. According to the progress of formulation study, green tea components will be guaranteed materials for the more effective skin cue products.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.4
• /
• pp.1197-1205
• /
• 2018

UV protection cosmetics belong to functional cosmetics and contain organic or inorganic UV blocking pigments. The inorganic UV blocking pigments are mainly zinc oxide and titanium dioxide. It is known that inorganic UV blocking pigment has a diameter of 60 to 100 nm and has good blocking ability of UVA and UVB. Also, it has high inactivity against sunlight including UV and is excellent in safety. In addition, it is not absorbed or accumulated on the skin like organic pigments and does not cause skin irritation or allergy. In this study, mica, a plate-shaped inorganic pigment, nanosized titanium dioxide, an UV blocking material, and hydrophobic silica were surface-treated with surfactants. And then, titanium dioxide nanoparticles and silica were physically adsorbed on the mica by non-chemical mutual attraction due to differences in charge. Thereafter, the mica complex was surface-treated with silane to prepare a hydrophobic UV blocking pigment complex. The plate-shaped UV blocking composite improves the cohesiveness of a general nanoparticle material titanium dioxide, enhances UV blocking effect due to uniform dispersion, and can greatly improve dispersion stability in cosmetic formulations by surface treatment with hydrophobic property. The surface charge of the pigment was evaluated by zeta potential. The properties of the UV blocking pigment complex were evaluated by FE-SEM, XRD, FT-IR and UV-VIS.