1.Brazilin and Caesalpinia sappan L. extract protect epidermal keratinocytes from oxidative stress by inducing the expression of GPX7.
Hyung Seo HWANG ; Joong Hyun SHIM
Chinese Journal of Natural Medicines (English Ed.) 2018;16(3):203-209
Caesalpinia sappan L., belonging to the family Leguminosae, is a medicinal plant that is distributed in Southeast Asia. The dried heartwood of this plant is used as a traditional ingredient of food, red dyes, and folk medicines in the treatment of diarrhea, dysentery, tuberculosis, skin infections, and inflammation. Brazilin is the major active compound, which has exhibited various pharmacological effects, including anti-platelet activity, anti-hepatotoxicity, induction of immunological tolerance, and anti-inflammatory and antioxidant activities. The present study aimed to evaluate the antioxidant activity and expression of antioxidant enzymes of C. sappan L. extract and its major compound, brazilin, in human epidermal keratinocytes exposed to UVA irradiation. Our results indicated that C. sappan L. extract reduced UVA-induced HO production via GPX7 activation. Moreover, brazilin exhibited antioxidant effects that were similar to those of C. sappan L. via glutathione peroxidase 7 (GPX7), suggesting that C. sappan L. extract and its natural compound represent potential treatments for oxidative stress-induced photoaging of skin.
Antioxidants
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pharmacology
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Benzopyrans
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pharmacology
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Caesalpinia
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chemistry
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Humans
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Hydrogen Peroxide
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toxicity
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Keratinocytes
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cytology
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drug effects
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enzymology
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radiation effects
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Oxidative Stress
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drug effects
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radiation effects
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Peroxidases
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genetics
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metabolism
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Plant Extracts
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pharmacology
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Protective Agents
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pharmacology
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Ultraviolet Rays
2.PKC alpha induces differentiation through ERK1/2 phosphorylation in mouse keratinocytes.
Haeng Ran SEO ; Yoo Wook KWAN ; Chul Koo CHO ; Sangwoo BAE ; Su Jae LEE ; Jae Won SOH ; Hee Yong CHUNG ; Yun Sil LEE
Experimental & Molecular Medicine 2004;36(4):292-299
Epidermal keratinocyte differentiation is a tightly regulated stepwise process that requires protein kinase C (PKC) activation. Studies on cultured mouse keraitnocytes induced to differentiate with Ca2+ have indirectly implicated the involvement of PKC alpha isoform. When PKC alpha was overexpressed in undifferentiated keratinocytes using adenoviral system, expressions of differentiation markers such as loricrin, filaggrin, keratin 1 (MK1) and keratin 10 (MK10) were increased, and ERK1/2 phosphorylation was concurrently induced without change of other MAPK such as p38 MAPK and JNK1/2. Similarly, transfection of PKC alphakinase active mutant (PKC alpha- CAT) in the undifferentiated keratinocyte, but not PKC beta-CAT, also increased differentiation marker expressions. On the other hand, PKC alphadominant negative mutant (PKC beta-KR) reduced Ca2+ -mediated differentiation marker expressions, while PKC beta-KR did not, suggesting that PKC alphais responsible for keratinocyte differentiation. When downstream pathway of PKC alphain Ca2+ - mediated differentiation was examined, ERK1/2, p38 MAPK and JNK1/2 phosphorylations were increased by Ca2+ shift. Treatment of keratinocytes with PD98059, MEK inhibitor, and SB20358, p38 MAPK inhibitor, before Ca2+ shift induced morphological changes and reduced expressions of differentiation markers, but treatment with SP60012, JNK1/2 inhibitor, did not change at all. Dominant negative mutants of ERK1/2 and p38 MAPK also inhibited the expressions of differentiation marker expressions in Ca2+ shifted cells. The above results indicate that both ERK1/2 and p38 MAPK may be involved in Ca2+- mediated differentiation, and that only ERK1/2 pathway is specific for PKCa-mediated differentiation in mouse keratinocytes.
Animals
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Calcium/pharmacology/physiology
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Cell Differentiation/physiology
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Intermediate Filament Proteins/analysis/metabolism
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Keratinocytes/cytology/*enzymology
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Membrane Proteins/analysis/metabolism
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Mice
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Mitogen-Activated Protein Kinase 1/*metabolism
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Mitogen-Activated Protein Kinase 3/*metabolism
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Phosphorylation
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Protein Kinase C/genetics/*physiology
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Research Support, Non-U.S. Gov't
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p38 Mitogen-Activated Protein Kinases/metabolism