Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1998-12-21
2001-07-24
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C514S969000, C514S846000
Reexamination Certificate
active
06264962
ABSTRACT:
The invention relates to the use of cinnamic acid, or of at least one of its derivatives, in a cosmetic composition as an agent for promoting the synthesis of skin lipids.
In particular, the compositions of the invention are intended to stimulate the synthesis of the skin's total lipids, particularly those of the epidermis.
The invention also relates to a cosmetic composition comprising an effective amount of cinnamic acid or of at least one of its derivatives.
Human skin consists of two compartments, i.e. a deep compartment, the dermis, and a superficial compartment, the epidermis.
The dermis gives the epidermis a solid support. It is also the epidermis' nourishing factor. It consists mainly of fibroblasts and of an extracellular matrix composed mainly of collagen, elastin and a substance known as ground substance, these components being synthesized by the fibroblasts. Leukocytes, mastocytes and tissue macrophages are also found therein. It also contains blood vessels and nerve fibres.
The epidermis is in contact with the external environment. Its role consists in protecting the body against dehydration and external attack, whether of chemical, mechanical, physical or infectious nature.
Natural human epidermis is composed mainly of three types of cells: the keratinocytes, which form the great majority, the melanocytes and the Langerhans cells. Each of these cell types contributes, by virtue of its intrinsic functions, towards the essential role played in the body by the skin.
The cells constituting the epidermis are bounded by an intercellular lipid region. During differentiation, phospholipids, whose role consists in developing the fluid structure of the cell membranes of the live layers of the epidermis, are gradually replaced by a mixture composed mainly of fatty acids, cholesterol and sphingolipids.
These lipids are organized into specific lamellar structures whose integrity depends not only on the quality of the fractions present but also on their respective proportion. This lamellar structure of the lipids in the intercellular lipid region of the epidermis is responsible for the skin's fluidity, and thus its suppleness.
The lipids are also responsible for the “barrier” properties of the epidermis, particularly of the stratum corneum.
The epidermal lipids are mainly synthesized in the live epidermis. They consist mainly of phospholipids, sphingolipids, cholesterol, free fatty acids, triglycerides, cholesterol esters and alkanes.
Phospholipids are essential for making up cell membranes. They play an important role in mediating extracellular signals and in forming free aliphatic chains used for the production of energy. They constitute a reserve of free fatty acids needed to make up the sphingolipids.
Sphingolipids (or ceramides) are essential for maintaining the multilamellar structure of the intercorneocytic lipids. They are also essential for water exchanges and for the “barrier” function of the epidermis.
Cholesterol plays a prime role in moisturization of the skin and in the “barrier” function of the epidermis.
Free fatty acids play a major role in maintaining the lamellar structure of the lipids in the stratum corneum, but also in making up cell membranes in which they are responsible for the membrane fluidity as well as for physiological processes such as the functioning of receptors or enzymatic activity.
The essential role played by skin lipids and the importance which their integrity entails can thus be appreciated.
It is known, unfortunately, that the lipids in the skin, particularly in the epidermis, are influenced by genetic factors, ageing, dietary habits, the seasons, environmental factors, external attack and/or certain pathologies (for example scurvy or pellagra). The consequence of all these factors is to adversely affect or modify the composition of the skin lipids or to decrease the amount therein, which invariably leads to dry skin. It is known, for example, that the absence of the lipid component in a diet has the consequence of skin in a poor state of health. The absence of lipids leads to general deterioration of the state of health and particularly to the appearance of flaky skin which increases as the trans-epidermal loss of water increases.
The skin's lipids are thus essential in maintaining the skin's water “barrier”.
It is also known that the lipids in the epidermis also have an influence on the activity of certain skin enzymes involved in the maturation and desquamation of the stratum corneum.
Variations in the levels and types of lipids present in the stratum corneum thus influence the “barrier” function of the stratum corneum, the water content and the condition of the skin.
It is also known that during the menopause women complain that their skin feels tight and that it takes on the appearance of “dry skin”, or even the appearance of xerosis. Without wishing to establish any particular theory, given that the skin lipids play an important role in moisturizing the skin and that the hormonal deficiencies associated with the menopause are accompanied by a general slowing-down in cell metabolism, it can nevertheless be assumed that the sensation of tightness of the skin or of dry skin which is experienced by women is linked in particular to a decrease in the amount of total lipids in the skin.
It can thus be appreciated that it is important to be able to stimulate the synthesis of skin lipids in order to maintain and/or restore their integrity, so as to allow them to carry out the important roles for which they are responsible.
In this regard, the Applicant has discovered, surprisingly and unexpectedly, that cinnamic acid or its derivatives have the property of stimulating the synthesis of lipids, particularly the skin's total lipids.
Cinnamic acid is present in trans form in the essential oils of basil or of cinnamon, in Peruvian balsam and in cocoa leaves. The cis form is present in the oil from
Alpinia malacensis.
In the prior art, cinnamic acid or its derivatives are known to be used in compositions for preventing bedsores (JP 07 242 558), as an anti-ultraviolet active agent (U.S. Pat. No. 5,093,109), in permanent-waving compositions (DE 3,301,515, DE 2,912,477 and EP 22,996), in hair lotions (JP 7,053,401 and JP 3,041,413), in depigmenting compositions (JP 5,221,845 and JP 1,186,811) and as antioxidant (EP 664,290).
To the Applicant's knowledge, the use of cinnamic acid or of its derivatives to stimulate the synthesis of the skin's total lipids has never been described in the prior art.
The subject of the invention is thus the use, in a cosmetic composition, of an effective amount of cinnamic acid or of at least one of its derivatives, the cinnamic acid or the composition being intended to stimulate the synthesis of the skin's total lipids.
The cinnamic acid or its derivatives can be of natural or synthetic origin. The term natural origin refers to cinnamic acid, or its derivatives, prepared from plant material in which they are found in the natural state. The term synthetic origin refers to cinnamic acid, or its derivatives, prepared by chemical synthesis or by biotechnology.
Thus, in the text hereinbelow, the term cinnamic acid is understood to denote cinnamic acid, or its derivatives, of natural or synthetic origin, in purified form or any preparation containing them.
Among the cinnamic acid derivatives which can be used according to the invention, mention may be made, for example, of mono- and polyhydroxycinnamic acids, alcohols, aldehydes, esters and derivatives.
Cinnamic acid is preferably used according to the invention.
Needless to say, it is possible according to the invention to use cinnamic acid or its derivatives alone or as a mixture.
It has been seen above that the lipids are involved, inter alia, in the skin's barrier function, in moisturization of the skin and in the suppleness of the skin. It has also been seen that the menopause induces effects on the skin, more particularly on the skin lipids.
Hence, one of the aspects of the invention is thus to propose the use, in a c
Breton Lionel
Girerd Florence
Renault Beatrice
Burns Doane Swecker & Mathis L.L.P.
Page Thurman K.
Societe L'Oreal S.A.
Ware Todd D
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