JP3129367B2 - Hyperkeratosis inhibitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agent for suppressing keratinization and an external preparation for skin containing the same, and more particularly to an agent for suppressing keratinization comprising an oxide of sterols and an external preparation for skin containing the same. .

[0002]

2. Description of the Related Art Keratinocytes, which occupy a large part of the epidermis, are finally differentiated by keratinization into keratinocytes having a strongly thickened cell membrane, which form the outermost stratum corneum, It protects living organisms physically and chemically. These keratinocytes periodically detach and fall off, but the keratinocytes are constantly keratinized, which keeps the stratum corneum at a constant thickness and keeps the water content of the stratum corneum constant. I have.

[0003] However, when the above keratinization is accelerated, keratinocytes are excessively generated, keratinous thickening occurs, and keratinized cells that cannot completely complete keratinization accumulate in the stratum corneum, resulting in skin keratinization. There are various problems such as wrinkles.

[0004] Conventionally, research and development on problems such as rough skin and wrinkles have been conducted mainly in the direction of controlling the water content of the stratum corneum. For example, good adhesion to the skin, a method of suppressing transpiration of stratum corneum water using a hydrophobic occlusive agent, or enhancing the skin hydration effect by using a polysaccharide represented by hyaluronic acid as a moisturizer The methods and the like all attempt to solve the problem of rough skin and wrinkles by keeping the water content of the skin stratum corneum sufficient.

[0005] However, even though these substances can prevent a decrease in the water content of the stratum corneum to some extent, they do not directly act on keratin thickening or dyskeratosis due to hyperkeratinization, but do not directly act on keratinization. However, this has not been an essential solution to problems such as rough skin and wrinkles.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made from the above viewpoint, and has an effect of sufficiently suppressing the hyperkeratosis of the skin and improving the change in skin condition such as rough skin and wrinkles. An object of the present invention is to provide a hyperplasia inhibitor and an external preparation for skin containing the same.

[0007]

Means for Solving the Problems In order to solve the above problems, the present inventors have collected substances derived from marine products and screened repeatedly using the keratinization-suppressing action as an index. As a result, stigmasterol, It has been found that sterols such as sterols and fucosterols have a slightly weakening keratinization-suppressing action, and in order to obtain a substance having a more excellent keratinization-suppressing action, various derivatives of these sterols are produced. However, as a result of re-screening, they found that keto bodies, which are oxides of these sterols, have a strong keratinization-inhibiting effect, and completed the present invention.

[0008] That is, the present invention is a keratinization-inhibiting agent comprising one or more selected from cholesterone, stigmasterone, campesterone, β-sitosterone, and fucosterone, and an external preparation for skin containing the same.

Hereinafter, the present invention will be described in detail.

<1> Hyperkeratosis inhibitor The keratinization inhibitor of the present invention comprises one or more members selected from cholesterone, stigmasterone, campesterone, β-sitosterone, and fucosterone.

These compounds are easily obtained by Oppenauer oxidation of cholesterol, stigmasterol, campesterol, β-sitosterol and fucosterol, respectively.

For example, cholesterol, stigmasterol, campesterol, β-sitosterol, and fucosterol can be converted to cyclohexanone using a nonpolar solvent such as toluene in the presence of a base such as potassium t-butoxide or aluminum isopropoxide. After oxidation with a ketone such as, if purified by a conventional method such as silica gel column chromatography, the above cholesterone, stigmasterone, campesterone, β-sitosterone,
Fucosterone is obtained.

The above-mentioned cholesterone, stigmasterone, campesterone, β-sitosterone, and fucosterone are all commercially available, and they can be used as the keratinization inhibitor of the present invention.

<2> External preparation for skin The external preparation for skin of the present invention contains the above keratinization inhibitor. The content is 0.1 to 1 with respect to the total amount of the external preparation.
0% by weight is preferred. If the content is less than 0.1% by weight,
Sufficient keratinization inhibitory action cannot be obtained, and even if the content exceeds 10% by weight, the effect levels off and is not economical.

[0015] The dosage form of the external preparation for skin of the present invention is not particularly limited, and examples thereof include those commonly used as external preparations for skin, such as ointments, creams, emulsions, lotions, packs, and bath preparations. Can be

The external preparation for skin of the present invention includes, in addition to the keratinization-inhibiting agent, various components generally used in external preparations for skin, that is, aqueous components, oily components, powder components,
Contains surfactants, moisturizers, thickeners, coloring agents, fragrances, preservatives, antioxidants, pH adjusters, chelating agents, or UV protection agents, anti-inflammatory agents, hormones, nucleic acids, various vitamins, etc. can do.

[0017]

The cholesterol, stigmasterone, campesterone, β-sitosterone, and fucosterone constituting the keratinization inhibitor of the present invention are each evaluated for the keratinization suppression effect and skin damage healing effect, and a local toxicity test is carried out. And evaluated its safety.

(1) Suppressing action of keratinization Since keratinization is considered to be caused by enhancing cell proliferation, the epidermis of the test substance determined by the following method is used as a parameter of the keratinization suppression action. The evaluation was performed using the growth inhibition rate for cell growth factor (EGF).

In 0.5 ml of Eagle's minimal medium (MEM) containing 10% fetal bovine serum (FBS),
2.5 × 10 ⁴ fibroblasts (balb / c 3T3
cells) was added to each well of a 24-well plate in an amount of 1 ml. After fibroblasts are saturated in a monolayer state, the fibroblasts are changed to MEM containing 1% FBS,
The cells were cultured at 7 ° C. and 5% CO ₂ for 12 hours.

Thereafter, 50 pg of mouse EGF was added to each well of the 24-well plate, and cholesterone, stigmasterone, campesterone, β-sitosterone, and fucosterone were each added at 0.
5 μg was added, and the control (n = 4) was cultured for 16 hours without adding anything other than mouse EGF. Thereafter, 0.5 μCi / 50 μl of ³ H-thymidine was added to each well, and the cells were further cultured for 8 hours.
After washing with a cooled isotonic phosphate buffer, 5% trichloroacetic acid was added and left for 30 minutes.

The supernatant was removed from each of the 24 test solutions, and the trichloroacetic acid precipitated fraction was dissolved in a 0.5 M aqueous sodium hydroxide solution, neutralized with 0.5 M hydrochloric acid, and a scintillator was added thereto. The radioactivity of ³ H-thymidine incorporated into the cells along with the proliferation was measured by counting with a liquid scintillation counter.

[0022] Here, the radioactivity values of ³ H- thymidine incorporated into the cells under a concurrent test substances Koresuteron was incorporated into the cells in the control cultures ³ H-
The percentage of the radioactivity value of thymidine was determined, and the percentage was used as the growth inhibition rate (%) to evaluate the cytostatic effect of the test substance on the cell growth promoted by EGF. Table 1 shows the results.

[0023]

[Table 1]

From these results, it was found that each of the substances constituting the hyperkeratosis inhibitor of the present invention was an epidermal growth factor (EG)
F) shows a high growth inhibitory effect on F) and clearly has an excellent keratinization inhibitory effect.

(2) Effect of Improving the Condition of Damage-Healing Skin The back of a group of six white Hartley female guinea pigs (weight: 350 to 500 g) was shaved and stripped four times with a gum tape. Until it becomes scabbed
Left for 5 days. Then, cholesterone, stigmasterone, campesterone,
A 10% liquid paraffin solution of β-sitosterone and fucosterone was applied at 0.05 ml / day for 3 days. Similarly, the control group was transdermally administered with liquid paraffin.

After completion of the administration, the above-mentioned portion was observed daily, and the number of days required until the skin became the same as the surrounding skin was examined. Table 2 shows the average number of healing days of six guinea pigs in each group.

[0027]

[Table 2]

As is apparent from the results, the guinea pigs to which the liquid paraffin containing the substance constituting the hyperkeratosis inhibitor of the present invention was transdermally administered were all guinea pigs to which only the liquid paraffin was transdermally administered. Compared to the group, the number of days required to change from a scab to a normal skin condition is shorter.

(3) Local toxicity test White Hartley female guinea pig (body weight 350-500)
Using g), the dermal toxicity of each substance constituting the keratinization-suppressing agent of the present invention was examined. That is, the back of ten guinea pigs was shaved to form six 2 cm × 2 cm portions, and cholesterone, stigmasterone, campesterone, β-sitosterone, a 10% liquid paraffin solution of fucosterone, and liquid paraffin were respectively formed in these portions. Was transdermally administered once a day for three consecutive days. Twenty-four hours after the final administration, the skin reaction was observed and evaluated based on the following Japanese Dermatological Association patch test standards in Japan.

-: No reaction ±: Pseudoerythema +: Erythema reaction ++: Edema reaction As a result, all the guinea pigs obtained an evaluation of-(no response) in all samples.

Thus, it can be seen that all the substances constituting the keratinization-suppressing agent of the present invention are safe for the skin.

[0032]

EXAMPLES Examples of the external preparation for skin containing the keratinization-suppressing agent of the present invention will be described below. In addition, the compounding amounts used below are all parts by weight.

[0033]

Examples 1 to 8 Oil-in-water cream The components A and B in Table 3 were each dissolved by heating at 80 ° C.
The component B was gradually added to the component A while stirring to emulsify.
This was cooled with stirring to obtain an oil-in-water cream. Similarly, an oil-in-water cream of Comparative Example not containing the keratinization-inhibiting agent of the present invention was produced.

[0034]

[Table 3]

[0035]

Example 9 Emulsion The components A, B and C in Table 4 were each dissolved by heating at 80 ° C.
The B component was added to the A component, and then the C component was gradually added to the mixture while stirring to carry out coarse emulsification. This was uniformly emulsified with a homomixer and then cooled with stirring to obtain an emulsion.

[0036]

[Table 4]

<Evaluation> The oil-in-water creams of Example 1 and Comparative Example obtained above were subjected to a practical use test for wrinkle improvement and skin roughness improvement.

(1) Wrinkle Improvement Test Forty female panelists (35 to 60 years old) were divided into two groups, one group containing the oil-in-water cream of Example 1 and the other group containing the oil-in-water cream of the comparative example. The cream was applied to the face twice a day, and the effect of improving wrinkles after continuous use for one month was evaluated. The evaluation was made by questionnaire evaluation and replica evaluation.

In the evaluation by the replica, the silicone replica obtained by copying the skin shape of the cheek to a silicone resin was fixed on a glass plate, and the diagonal direction (20
° C), irradiate parallel rays from above, take a picture with a TV camera from directly above, convert the light and shade of the shadow produced by the unevenness of the replica into brightness, and calculate the wrinkle length (maximum diameter) x the wrinkle depth (average (Width × tan 20 °)). Effective if this value decreases by 20% or more before and after the test. 10% or more 2
A decrease of less than 0% was judged to be slightly effective, and a decrease of less than 10% was judged to be invalid. Table 5 shows the results.

[0040]

[Table 5]

From these results, it is clear that the cream containing a keratinization-inhibiting agent of the present invention has an excellent wrinkle-reducing action as compared with the cream of Comparative Example not containing it.

(2) Skin roughness improvement effect Forty female panelists (30-50 years old) were divided into two groups, one group containing the oil-in-water cream of Example 1 and the other group containing the water-based cream of the comparative example. Oil cream was applied to the elbow twice a day as a hand cream, and the effect of improving skin roughness (crusty feeling) after continuous use for one month was evaluated. The evaluation was performed in the form of a questionnaire. Table 6 shows the results.

[0043]

[Table 6]

From these results, it is clear that the cream containing a keratinization-inhibiting agent of the present invention has an excellent skin roughness improving effect as compared with the cream of Comparative Example not containing it.

[0045]

EFFECT OF THE INVENTION The keratinization-inhibiting agent and the external preparation for skin containing the same according to the present invention have high safety, are excellent in keratinization-inhibiting effect, and further have a scab improving effect, a skin roughening improving effect and a wrinkle improving effect. It is also excellent in skin condition improving action such as improving action.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taku Hirose 27-1, Takashimadai, Kanagawa-ku, Kanagawa-ku, Yokohama-shi, Japan Inside the Polar Chemical Industry Co., Ltd. Yokohama Research Laboratory (72) Inventor Norie Muramatsu 27, Takashimadai, Kanagawa-ku, Yokohama-shi, Kanagawa 1 Polar Chemical Industry Co., Ltd. Yokohama Research Laboratory (72) Inventor Yoshikazu Hirai 27-27 Takashimadai, Kanagawa-ku, Kanagawa-ku, Kanagawa Prefecture 1 Polar Chemical Industry Co., Ltd. Yokohama Research Laboratory (72) Inventor Yasunori Inaoka Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa 560 POLA Kasei Kogyo Co., Ltd. Central Research Laboratory (72) Inventor Toshiyuki Fukuda 560 POLA Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Kasei Kogyo Co., Ltd. (72) Inventor Minoru Kashima Tsuku, Ibaraki Pref. 2-17-1 Kasuga-shi (72) Inventor Kunio Tsuji 1375-11 Ikeda, Shizuoka-shi, Shizuoka Prefecture (56) References JP-A-60-120805 (JP, A) JP-A-60-161912 (JP, A) JP-A-61-148111 (JP, A) JP-A-61-148196 (JP, A) JP-A-62-93216 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61K7 / 00-7/50 A61K 31/575 CA (STN)

Claims (3)

(57) [Claims] A keratinization inhibitor comprising one or more selected from cholesterone, stigmasterone, campesterone, β-sitosterone, and fucosterone. 2. An external preparation for skin containing the keratinization-suppressing agent according to claim 1. 3. The external preparation for skin according to claim 2, wherein the content of the keratinization enhancement inhibitor according to claim 1 is 0.1 to 10% by weight based on the total amount.