ABSTRACT
Hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, thus melanin synthesis inhibitors have been of great interest as target molecules for cosmetic and medicinal purposes. The aim of this study was to investigate the in vitro inhibitory effect of panduratin A, isolated from Kaempferia pandurata Roxb., on melanogenesis and its related enzymes such as tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) in melan-a murine melanocytes. The IC(50) values of panduratin A for melanogenesis and tyrosinase were 9.6 µm and 8.2 µm, respectively, while those of arbutin as a positive control were 990 µm and 660 µm, respectively. In western blot analysis, panduratin A also significantly decreased tyrosinase, TRP-1 and TRP-2 protein levels. These results indicate that panduratin A effectively inhibits melanin biosynthesis, thus creating the possibility of developing a new skin-whitening agent.
Subject(s)
Chalcones/pharmacology , Melanins/biosynthesis , Melanocytes/drug effects , Zingiberaceae/chemistry , Animals , Cell Line , Intramolecular Oxidoreductases/metabolism , Mice , Monophenol Monooxygenase/metabolism , Oxidoreductases/metabolismABSTRACT
Titanate nanotubes were synthesized by hydrothermal method using various TiO2 precursors as starting materials. The electrochemical properties were investigated by cyclic voltammetric methods. The microstructure and morphology of the synthesized powders were characterized by XRD, TEM. Titanate nanotubes composed of H2Ti2O5 x H2O with outer and inner diameter of approximately 10 nm and 6 nm, and the interlayer spacing was about 0.65 approximately 0.74 nm. Also, the titanate nanotubes showed a discharge capacity of 303 mAh/g and the highest cycle stability because of the open-end and rolled layers with suitable spacing. The relationships between morphology and electrochemical properties have been also discussed.
ABSTRACT
This study was carried out to investigate the in vitro effects of isopanduratin A and 4-hydroxypanduratin A isolated from Kaempferia pandurata ROXB. on melanin biosynthesis and tyrosinase activity. Two chalcone compounds, isopanduratin A and 4-hydroxypanduratin A, were isolated from the ethyl acetate fraction of ethanol extract as the active principles. Compared with phenylthiourea (IC(50)=34.3 microM) as a positive control, the depigmentation IC(50) values for isopanduratin A and 4-hydroxypanduratin A were 10.6 microM and 23.2 microM, respectively. The compounds also significantly inhibited the activity of tyrosinase, the enzyme that converts DOPA (3,4-dihydroxyphenylalanine) to dopachrome in the biosynthetic process of melanin. The IC(50) values of isopanduratin A and 4-hydroxypanduratin A for tyrosinase were 10.5 microM and >30 microM, respectively, while that of phenylthiourea was 47.6 microM. The tyrosinase protein level was also significantly decreased by isopanduratin A and 4-hydroxypanduratin A. The results indicate that isopanduratin A and 4-hydroxypanduratin A isolated from K. pandurata ROXB. are promising compounds that could be useful for treating hyperpigmentation as skin-whitening agents.
