Download PowerPoint

SKIN WHITENING AGENT
By:
Hala shindi
Maysam manasrah
Instructor: Yassen Qwassmi
What that gives skin its color:
Skin color results from the synthesis and distribution of
melanin in the skin , and produced by specialized cells,
termed melanocytes in the epidermis layer.
The melanins can be of two basic types:
1)Eumelanins, which are gives brown or black skin
color.
2)Phaeomelanins, which are gives red or yellow skin
color.
Synthetic of melanin
Melanocytes synthesize melanin within discrete
organelles, termed melanosomes, which can be produced
in varying sizes, numbers, and densities. The
melanosomes are then passed on, in skin to
keratinocytes, where the final distribution patterns of
the pigment are determined. This distribution plays an
important role in determining color.
Skin color is due to the type of pigments called melanin
granules cells called Almilanossit called melanin
production process on behalf of melanogenesis.
•This is the production of melanin in the inner layers of
the skin layer and in the dermis layer and then paid to the
surface layer of skin to skin to gain its distinctive color
• The occurrence or the beginning of melanin synthesis
due to the presence of amino acid called tyrosine and
tyrosine synthesis begins in the liver through the
conversion of phenylalanine to tyrosine phenylalanine by
the enzyme phenylalanine hydroxylase,.
What causes darkening of the skin
The main physiological stimulus of melanogenesis is the UV
radiation of solar light, which can act directly on melanocytes
or indirectly through the release of keratinocyte-derived
factors stimulating hormone).
Increased production and accumulation of melanins
characterize number of skin diseases, which include
hyperpigmentation such as melanoma, post-inflammatory
melanoderma, solar lentigo, etc. Several modalities of
treatment for these problems are available including
chemical agents or physical therapies.
Skin whitening agent:
Skin whitening products are commercially available for cosmetic
purposes in
order to obtain a lighter skin appearance.. Whitening agents act at
various levels of melanin production in the skin. Many of them are
known as competitive inhibitors of tyrosinase, the key enzyme in
melanogenesis. Others inhibit the maturation of this enzyme or the
transport of pigment granules (melanosomes) from
melanocytes to surrounding keratinocytes.
skin whitening agents work by depigmenting
activity :
Depigmentation can be achieved by:
(i) regulating the transcription and activity of
tyrosinase.
(ii) regulating the uptake and distribution of
melanosomes in recipient keratinocytes.
(iii) interference with melanosomes maturation and
transfer.
However, as a result of the key role played by
tyrosinase in the melanin biosynthesis, most
whitening agents acts specially to reduce the
function of enzyme by mean of several
mechanisms Therefore, tyrosinase inhibitors
have become increasingly important in the
cosmetic and medicinal products used in the
prevention of hyperpigmentaion and skin
whitening
NATURAL WHITENING
PRODUCTS
BLOCKING TYROSINASE
I. Phenols:
(I) Arbutin and Derivatives
isolated from the fresh fruit of
California buckeye the
inhibit the oxidation of L-DOPA
catalyzed by mushroom tyrosinase and
was effective in
the topical treatment of various cutaneous
hyperpigmentations
characterized by hyperactive melanocyte
function. Structurally related to
hydroquinone, arbutin
inhibited tyrosinase activity by interacting
at the active site with copper
(II) Kojic Acid and Derivatives
produced by several species of 
fungi, especially Aspergillus oryzae,
which has the Japanese common
name koji.
How it work ?
Kojic acid was a
tyrosinase inhibitor
derived from
various fungal species
such as Aspergillus and
Penicillium. Its function
was chelating copper at
the active site of the
tyrosinase and
scavenging free radicals
(III) Gentisic Acid and
Derivatives
found in gentian roots
good inhibitor
of melanogenesis. Its
alkyl esters were
investigated
as tyrosinase
inhibitors in vitro and
in cell cultures.
Methyl gentisate
appeared to be more
efficient than the
free acid form as well
as other well-known
hypopigmenting
Agents.
II. Polyphenols
Polyphenols are a group of chemical compounds
that are widely distributed in nature and are also known
as tannins because they are responsible for the colors of
many flowers.
(I) Flavonoids
Abundantly present in acid fruits
known as "citrus" - oranges, lemons,
tangerines and grapefruit
Flavonoids inhibit enzymes due to
abilities to chelate copper at their
site .A recent the active
fluorescence quenching study
demonstrated that dihydroxy
substitutions in both rings of
flavonoids are crucial for tyrosinase
inhibitory
activity
(II) Aloesin
Aloesin was a glycosylated chromone
isolated from the aloe plant
Its structure was rather similar
to flavonols. It modulated
melanogenesis via competitive
inhibition of tyrosinase . Combined
treatment
of aloesin and arbutin seemed to show
synergistic effects by respectively
non-competitive and competitive
tyrosinase inhibition
)
.
(III) Procyanidins
Procyanidins, polymers of catechins
found in tea and fruits such as apples
and grapes
Procyanidins had been recently introduced
as inhibitors of melanogenesis. Procyanidinrich
extract would reduce DOPA-postive
melanocytes and 8-hydroxy-2′-deoxyguanosine
positive melanin containing cells, and this
effect may related to inhibition of tyrosinase
(IV) Ellagic Acid
Ellagic acids (EA) was a polyphenol
found in berries, green tea and pomegranate
with strong
antioxidative properties and tyrosinase
inhibition .
The skin lightening effects of EA may due to
chelating
copper at the active site of tyrosinase to
reduce its activity
and inhibition of proliferation of
melanocytes and
melanin synthesis .
(68)
(
67)
(68)
Risks and detriments
• Some people are developing skin lightening cream on
the entire body in order to change the color of their
skin completely. This action involves high risk, as a
active ingredients in some skin lightening creams is
mercury, and this has led practically to the incidence
of mercury poisoning.
Mercury is a toxic elements, which can cause
psychological problems and serious neurological damage
in addition to the kidney. Can pregnant women who use
skin lightening creams containing mercury (Mercury)
that Ikmn passing mercury to their unborn.
•also hydroquinone which are used to
relieve the activity of cells when
Irritation of the pigment melanin in the
body, they greatly harm a pregnant
woman ,and is considered to be highly
cytotoxic to melanocytes , It can be
irritating and causes redness and
burning , impaired
wound healing
• And cortisone
Cortisone material is considered hazardous
material and cause when used for skin
lightening in skin atrophy and increased hair
growth In some areas of the body.
Side effects of skin whitening
application:
• Dermatitis with severe drying, cracking of the skin
and itching
• Melasma and hyperpigmentation of the skin
• Mercury poisoning
• Fetal toxicity in pregnant women
• Cushing’s syndrome
• Liver failure
• Skin cancer
.
The hypopigmentation (lack
of skin pigment) leaves the skin
prone to UV damage by sunlight.
This can predispose to skin
cancers
like a melanoma. Therefore, you
should use sunscreens
T h a n k
y o u
f o r
l i s t e n i n g
y o u r