ABSTRACT
This study reports the effects of oral Aloe vera gel powder (AVGP) containing Aloe sterols on skin elasticity and the extracellular matrix in ultraviolet B (UVB)-irradiated hairless mice. Ten-week-old hairless mice were fed diets containing 0.3% AVGP for 8 weeks and irradiated UVB for 6 weeks. Mice treated with AVGP showed significant prevention of the UVB-induced decrease in skin elasticity. To investigate the mechanism underlying this suppression of skin elasticity loss, we measured the expression of matrix metalloproteinase (MMP)-2, -9, and -13. AVGP prevented both the UVB-induced increases in MMPs expressions. Moreover, we investigated hyaluronic acid (HA) content of mice dorsal skin and gene expression of HA synthase-2 (Has2). In the results, AVGP oral administration prevented UVB-induced decreasing in skin HA content and Has2 expression and attenuates the UVB-induced decrease in serum adiponectin, which promotes Has2 expression. These results suggested that AVGP has the ability to prevent the skin photoaging.
Subject(s)
Aloe/chemistry , Elasticity/drug effects , Matrix Metalloproteinase 2/genetics , Plant Extracts/pharmacology , Skin Aging/drug effects , Skin/drug effects , Adiponectin/blood , Adiponectin/genetics , Administration, Oral , Animals , Elasticity/physiology , Elasticity/radiation effects , Extracellular Matrix/drug effects , Extracellular Matrix/metabolism , Extracellular Matrix/radiation effects , Female , Gels/chemistry , Gels/pharmacology , Gene Expression Regulation , Glucuronosyltransferase/genetics , Glucuronosyltransferase/metabolism , Hyaluronan Synthases , Hyaluronic Acid/biosynthesis , Matrix Metalloproteinase 13/genetics , Matrix Metalloproteinase 13/metabolism , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/metabolism , Mice , Mice, Hairless , Plant Extracts/chemistry , Powders , Skin/radiation effects , Skin Aging/radiation effects , Ultraviolet Rays/adverse effectsABSTRACT
The constitutive androstane receptor (CAR) is known as a xeno-sensor that regulates genes involved in xenobiotic excretion and energy metabolism. This study tested a variety of polyphenols for their ability to modulate CAR activity. HepG2 cells were transfected with a CAR expression plasmid and a reporter plasmid containing the human CYP2B6 regulatory region and then treated with flavonoids, catechins, and other bioactive polyphenols. Luciferase assays revealed that baicalein (5,6,7-OH flavone) was a potent activator of both human and mouse CAR. Catechin gallates also activated human and mouse CAR. Wild-type and CAR knockout mice were treated with baicalein and chrysin (5,7-OH flavone), and their liver mRNA was analyzed by real-time polymerase chain reaction (PCR). A significant increase in cyp2b10 mRNA content was observed only in wild-type mice fed chrysin. These results suggest that dietary flavonoids regulate CAR activity and thereby accelerate both detoxification and energy metabolism.
