1. Natural Products Laboratory, Daebong LS Co., Ltd., Incheon, Republic of Korea
2. Division of Fine Chemicals Polymers, Nanomaterials, Pai Chai University, Republic of Korea
Jade has been the most favorite and noble ornamental stone in Korean traditional fashion and aesthetic life since pre-historic time. It is now used for cabochons, rings, beads, bracelets, drop earrings and carvings. It can even be carved into super quality endless chains by artists. There are two kinds of jade: nephrite, a variety of amphibole, and jadeite, a pyroxene. Jade from Chuncheon city area, Korea, consists of nephrite has been produced and traded under the name ‘Chuncheon Ock‘ (meaning Chuncheon jade) or ‘Baek Ock‘ (meaning white jade) since 1976.
Nowadays, most people live in urban areas and they are exposed to and influenced by urban pollutants on daily basis. Our skin directly exposed to polluted environment has to deal with all the harsh chemical releases into the environment. Heavy metals, chemical elements commonly found in our environment, are poisonous at high doses and cause human health problems even at fairly low concentrations. Malondialdehyde MDA is a naturally occurring product of lipid peroxidation. Lipid peroxidation is a wellestablished mechanism of cellular injury for both plants and animals and is used as an indicator of oxidative stress in cells and tissues. Therefore, heavy metals and MDA is used for cytotoxicity and oxidative stress assay.
Although there have been examples of White Jade Powder usage in cosmetics to grant image of high quality since it is jewelry stone, there is no precedent development or activity report of surface-coated white jade powder (White Jade Powder-S), especially using hydrophobic surface coat. In this study, noble type of cosmetic powder is developed by treating White Jade Powder with polymethylsilsesquioxane and triethoxycaprylylsilane for hydrophobicity and its amelioration of heavy metal induced cytotoxicity and oxidative stress is investigated.
Grinding & particle size distribution analysis: Jade purchased from jade mine in Chuncheon, Korea is dried after wet grinding using ball mill. Grinded and dried jade powder is added into water and analyzed using HORIBA Laser Scattering Particle Size Distribution Analyzer LA-950 after homogenization by ultrasound treatment.
Surface coating: White Jade Powder is treated with polymethylsilsesquioxane and triethoxycaprylylsilane for hydrophobicity.
Heavy metals induced cytotoxic and oxidative stress:
1) Cell culture -HaCaT human keratinocytes were purchased from Dr. Hyun (Jeju National Unv.). The cells were cultured in DMEM supplemented with 10% (v/v) heat-activated FBS, streptomycin (100 μg/ml) and penicillin (100 U/ml) and incubated at 37°C with 5% CO2.
2) Cell viability-The cell viability assay was performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) (Sigma, USA). The cells (1 × 10^5 cells/well) were seeded into a 48-well plate and cultured overnight, and then were exposed to white jade powder and cadmium for 2 h followed by the addition of MTT solution to the wells. The insoluble derivative of MTT produced by intracellular dehydrogenase was solubilized in dimethyl sulfoxideDMSO. The absorbance of each well at 570 nm was read using a microplate reader.
3) Assay of malondialdehyde concentration-The lipid peroxide concentration was determined by experimental method measuring amount of thiobarbituric acidTBA reactivity and malondialdehydeMDA formed during lipid peroxidation.
Particle size of White Jade Power: 99% of White Jade Powder particles are determined to be pulverized into size of 15 ㎛ or less by ball mill.
Heavy metals induced cytotoxic and oxidative stress: cadmium-induced cytotoxicity was reduced by co-treatment with White Jade Powder-S. MDA production was significantly decreased by White Jade Powder-S treatment in concentration-dependent manner.
In conclusion, noble type of powdered white jade coated with polymethylsilsesquioxane and Triethoxycaprylylsilane for hydrophobicity is developed. It can be applied as useful cosmetic powder showing cytotoxicity and oxidative stress ameliorating activities.