lignans and Dermatitis--Contact

Ultraviolet (UV) radiation exposure induces immunosuppression, which contributes to the development of cutaneous malignancies. We investigated the effects of honokiol, a phytochemical found in plants of the genus Magnolia, on UVB-induced immunosuppression using contact hypersensitivity (CHS) as a model in C3H/HeN mice. Topical application of honokiol (0.5 and 1.0 mg/cm

Topics: Animals; Biphenyl Compounds; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dermatitis, Contact; DNA Methylation; Female; Immunosuppression Therapy; Inflammation; Inflammation Mediators; Lignans; Methyltransferases; Mice; Models, Biological; Protective Agents; Proto-Oncogene Proteins; Skin; Ultraviolet Rays

Magnolol has been reported to have an anti-inflammatory and antitumor effect in vitro and in vivo. Herein, we report the investigation of the inhibitory effects of magnolol on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in mouse skin. We found that the topical application of magnolol effectively inhibited the transcriptional activation of iNOS and COX-2 mRNA and proteins in mouse skin stimulated by TPA. Pretreatment with magnolol resulted in the reduction of TPA-induced nuclear translocation of the nuclear factor-kappaB (NFkappaB) subunit and DNA binding by blocking the phosphorylation of IkappaBalpha and p65 and subsequent degradation of IkappaBalpha. In addition, magnolol can suppress TPA-induced activation of extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)/Akt, which are upstream of NFkappaB. Moreover, magnolol significantly inhibited 7,12-dimethylbene[a]anthracene (DMBA)/TPA-induced skin tumor formation by reducing the tumor multiplicity, tumor incidence, and tumor size of papillomas at 20 weeks. All these results revealed that magnolol is an effective antitumor agent and that its inhibitory effect is through the down-regulation of inflammatory iNOS and COX-2 gene expression in mouse skin, suggesting that magnolol is a novel functional agent capable of preventing inflammation-associated tumorigenesis.

Topics: Animals; Base Sequence; Biphenyl Compounds; Carcinogens; Dermatitis, Contact; DNA Primers; Electrophoretic Mobility Shift Assay; Lignans; Mice; Neoplasms, Experimental; Reverse Transcriptase Polymerase Chain Reaction; Tetradecanoylphorbol Acetate

Oral administration of a methanolic extract of Piper nigrum leaf (PN-ext, 50, 200 and 500 mg/kg) showed a potent dose-dependent inhibition of dinitrofluorobenzene (DNFB)-induced cutaneous reaction at 1 h [immediate phase response (IPR)] after and 24 h [late phase response (LPR)] after DNFB challenge in mice which were passively sensitized with anti-dinitrophenyl (DNP) IgE antibody. Ear swelling inhibitory effect of PN-ext (50, 200 and 500 mg/kg, per os (p.o.)) on very late phase response (vLPR) in the model mice was significant but weaker than that on IPR. Oral administration of PN-ext (50, 200 and 500 mg/kg for 7 d) inhibited picryl chloride (PC)-induced ear swelling in PC sensitized mice. PN-ext exhibited in vitro inhibitory effect on compound 48/80-induced histamine release from rat peritoneal mast cells. Two lignans of PN-ext, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), were identified as major active principles having histamine release inhibitory activity.

Topics: Animals; Dermatitis, Contact; Female; Histamine Release; Hypersensitivity, Immediate; Lignans; Mast Cells; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; p-Methoxy-N-methylphenethylamine; Picryl Chloride; Piper nigrum; Plant Extracts; Plant Leaves

Sesame oil has been reported to contain sesamolin, sesamin and sesamol as contact allergens. A female patient had cheilitis due to sesame oil in a lipstick. She reacted to sesamolin and sesamin, but not to sesamol. We carried out analysis of the sesame oil by high performance liquid chromatography. We detected sesamolin and sesamin but not sesamol in sesame oil.

Topics: Adult; Benzodioxoles; Cheilitis; Chromatography, High Pressure Liquid; Dermatitis, Contact; Dioxoles; Female; Humans; Lignans; Patch Tests; Phenols; Plant Oils; Sesame Oil