Skin can age in two ways: (i) intrinsic or chronologic aging, which is the process of senescence that affects all body organs; and (ii) extrinsic aging which occurs as a consequence of exposure to environmental factors including sunlight and cigarette smoke. 1)The most important of these factors is sunlight, particularly exposure to ultraviolet (UV)B irradiation, which causes photoaging. The photoaging process increases skin fragility, laxity, blister formation, leathery appearance and formation of wrinkles. 2)UVB induces the production of matrix metalloproteinases (MMPs) by activating cellular signaling transduction pathways 3) ; MMPs are responsible for the degradation or synthesis inhibition of collagenous extracellular matrix in connective tissues.3) Collagen represents the main component of the extracellular matrix of dermal connective tissue, and its concentration decreases in chronoaging and photoaging.All matrix macromolecules in the dermis can be digested by MMPs acting alone or in combination. The MMPs form a family of structurally and functionally related zinc endopeptidases that exhibit various substrate specificities. 4) Once collagen is initially cleaved by MMP-1, MMP-3 and other MMPs, collagen breakdown is further promoted. The enzyme mainly responsible for collagen breakdown in skin is, MMP-1 (fibroblast collagenase), which cleaves type I, III, VII, VIII and X collagen.Human fibroblast collagenase was the first vertebrate collagenase both purified to homogeneity as a protein, and cloned as a cDNA. This enzyme has been designated as matrix metalloproteinase-1 (MMP-1) and has served as the prototype for all the interstitial collagenases. MMP-1 is also known as collagenase-1. Starting from the N terminus the following features of domain organization are observed. 5)The pre-domain specifies a signal rich in hydrophobic amino acids that destines the synthesized polypeptide to the endoplasmic reticulum where it is removed during the transportation of the molecule from the cell to the outside. The propeptide domain indicates a sequence that is responsible of keeping the pro-form inactive. It presents a cysteine residue 73 that is located in a conserved sequence PRCGVPD opposite to a zinc atom at the active-form site and coordinated to it through an -SH group. The enzymatic activity of the proform enzyme is turned on by the displacement of this cysteine residue ("cysteine switch") and occurs by proteolytic cleavage, or by chemical disruption as in the case of oxidation or treatment with mercurial compounds. 6)Recent studies have shown that hairless mice exposed to UVB developed wrinkled skin and significantly enhanced MMP-1 mRNA expression. However, they have shown that the inihibition of MMP-1 activities by a specific MMP inhibitor suppresses UVB-induced wrinkle formation.7) This evidence suggests that MMP-1 plays a major role in the process of photoaging.Brown seaweed has been a staple of both Korean and Japanese diets and has also been documented as being used in traditional Chinese medicine for over ...

Fucoidans are sulfated fucosylated polymers from the cell wall of brown algae. We assessed the effects of Fucus evanescens fucoidan on ultraviolet-B (UVB)-induced expression of matrix metalloproteinase-1 (MMP-1) protein, mRNA, and promoter, and the phosphorylation of mitogen-activated protein kinases in vitro using an immortalized human keratinocyte cell line. Pretreatment with 10 and 100 μg/ml fucoidan significantly inhibited UVB-induced MMP-1 protein, mRNA and promoter activity, compared to UVB irradiation alone. Extracellular signal regulated kinase activation was markedly inhibited by treatment with fucoidan, though c-JUN N-terminal kinase activity and p38 activation were only marginally affected by fucoidan. F. evanescens fucoidan may be a potential therapeutic agent for the prevention and treatment of skin photoaging.

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