Melanin is a complex polymer derived from the amino
acid tyrosine. Melanin is responsible for determining skin
and hair colour and is present in the skin to varying degrees; depending on how
much a population has been exposed to the sun historically. Melanin is produced
within the skin in
cells called melanocytes and it is the main determinant of the skin color of
darker-skinned humans. The skin color of people with light skin is determined mainly by
the bluish-white connective tissue under the dermis and by the hemoglobin
circulating in the veins of the dermis. There are two types of melanin in mammals, the brownish black eumelanin
and the reddish yellow pheomelanin (Thody et
al., 1991). In human
epidemic layer, melanin pigment is synthesized and protects the inner skin from
damage caused by UV rays. Over production or accumulation of melanin can induce
epidermis pigmentation disorders including Melasma & Freckles (Baumann,
2002).
Tyrosinase is a copper-containing enzyme present in plant
and animal tissues that catalyzes the production of melanin and other pigments
from tyrosine by oxidation, as in the blackening of a peeled or sliced potato
exposed to air. In melanin synthesis, tyrosinase catalyses the oxidation of l-tyrosine to 3,
4-dihydroxyphenylalanine (L-DOPA), and further to DOPA quinone. This DOPA
quinone is chemically reactive so it eventually converted to melanin polymers
by a series of subsequent reaction (Uyen et
al., 2008).A
number of studies for melanogenic inhibitory compounds are using in the hope of
preventing or curing these hyperpigmentory disorders. Compounds such as
hydroquinone, ascorbic acid derivatives, kojic acid, azelaic acid,
corticosteroids, retinoids, arbutin, licorice extract, and compounds from Streptomyces, paper-mulberry compounds,
green tea compounds, and others have been reported (Garcia & Fulrton, 1996;
Kojima et al., 1995; Cabanes et al., 1994; Verallo-Rowell et al., 1989; Takiwake et al., 1994; Kimbrough-Green et al., 1994; Maeda et al., 1996; Yokota et al.,
1998; No et al., 1999; Jang et al., 1997; Tomita et al., 1990) to show the tyrosinase
inhibitory effect. However, these compounds can cause adverse effects mostly in
the form of skin irritation.
That
is why our aim is to isolate and identify the new natural compound from
bacteria and to examine the mechanism of action and supporting clinical studies
used for depigmenting agents in cosmeceuticals.
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