Daniel Schmid, Esther Belser, Sandra Meister 
Mibelle Biochemistry, Buchs, Switzerland

CosmeticsDesign Europe & .Com  (February 2007)

As known tyrosine kinase inhibitor and slightly estrogenic active, genistein, the bioactive form of the predominant soy isoflavones, has a big potential to stimulate collagen in the skin. A clinical skin penetration study showed that there is no in situ activation of biologically inactive isoflavone glycosides. The study showed further that only genistein encapsulated into lecithin liposomes penetrates into deeper stratum corneum layers. In another clinical study, a cream with liposomal genistein was found to significantly increase skin thickness, firmness and hydration.               download pdf

Topically-Applied Soy Isoflavones Increase Skin Thickness

Daniel Schmid and Fred Zülli
Mibelle AG Cosmetics, Buchs, Switzerland

Cosmetics & Toiletries 117 (6): 45 - 50 (2002)

Epidemiological studies indicating an association between diet and disease led to the investigation of a series of bioactive plant compounds. In Japan, for example, the incidences of cardiovascular disease, hormone-dependent cancers (breast, uterus and prostate) and menopausal symptoms (osteoporosis and hot flashes) are all substantially lower than in western countries. The traditional Japanese diet includes a significant amount of soy-based foods such as tofu and tempeh.

The physiologically-relevant compounds in soy are the isoflavones, a subgroup of polyphenolic plant compounds. Isoflavones, or phytoestrogens, adopt a chemical structure very similar to that of the human hormone estrogen after hydrolysis of the sugar moiety. The isoflavones contained in soybeans appear predominantly in the form of polar, water-soluble glycosides, such as genistin.

Many dietary supplements with soy isoflavones already exist. In most cases, supplements contain only isoflavone glycosides, the molecular form that is not biologically active because there is no cellular uptake of glycosides. However, after ingestion, intestinal glucosidases and intestinal bacterial metabolism transform the glycosides into the physiologically active form.

There is an interest in isoflavones in the cosmetic industry because these compounds may have potential in the treatment of skin aging. We assume that two different activities of isoflavones could affect the skin by binding estrogen receptors and inhibiting the protein tyrosine kinase-signaling pathway.

Since the skin does not have the hydrolytic activity of the intestine, the isoflavones must be in the active aglycone form for skin care applications. In this rather apolar form, isoflavones penetrate easily into deeper skin layers and into the skin cells. Unfortunately, these aglycones have a poor solubility in water and in oil. We have therefore developed a process to produce a water-soluble isoflavone aglycone preparation based on liposomes that is suitable for cosmetic applications, which we have reported previously. This article summarizes the first study conducted on the efficacy of isoflavones in the prevention of skin aging.

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Genistein, a New Cosmetic Ingredient Derived from Soy

D. Schmid, Chr. Hanay, R. Muggli, F. Zülli
Mibelle AG Cosmetics, Bolimattstrasse 1, 5033 Buchs, Switzerland

SÖFW-Journal 127 (10): 22 - 27 (2001)

Soy isoflavones are already widely used as functional food ingredients. In most cases, these food supplements contain only isoflavone glycosides, the molecular form that is biologically not active. However, after digestion the glycosides are transformed by intestinal glycosidases and intestinal bacterial metabolism into the estrogenically active from. Since the skin does not harbour such bacteria and enzymes, the active isoflavone preparations for skin care must be in the form of aglycones. Unfortunately, these aglycones have a poor solubility in water and oil. Thus, a special galenic form is necessary to introduce these isoflavone reparations into cosmetic formulations.

We developed a soy isoflavone preparation suitable for cosmetic applications. It contains the biologically active aglycone genistein in pure form. Our genistein formulation is based on liposomes to make the aglycone water dispersible and bioavailable to the skin.

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Dermatological Application of Soy Isoflavones to Prevent Skin Aging in Postmenopausal Women

Schmid Daniel, Muggli Reto and Zülli Fred
Mibelle AG Cosmetics, Bolimattstrasse 1, 5033 Buchs, Switzerland

Cosmetics and Toiletries Manufacture Worldwide 2001: 146 - 151

Isoflavones from soy beans are used in functional food products as a measure to alleviate hormone-dependent physiological disorders such as postmenopausal symptoms, osteoporosis and cardiovascular problems. These natural phytohormones are well perceived and do not show the negative side effects found in conventional therapies with hormones such as estrogens. A number of studies show that estrogens can slow down the aging process of the skin in postmenopausal women. For this reason, isoflavones from soy beans are also very interesting compounds for cosmetic formulations. We succeeded in isolating very pure fractions of isoflavones in the form of the active aglycones suitable for cosmetic applications. We herein report the use of this aglycone preparation in the treatment of post menopause skin and discuss further applications.

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Penetration and Metabolism of Isoflavones in Human Skin

D. Schmid, F. Zuelli,Mibelle AG Cosmetics, Buchs, Switzerland
H.-P. Nissen, H. Prieur, Derma Consult GmbH, Alfter, Germany

Cosmetics & Toiletries 118 (9): 71 - 74 (2003)

This human study shows, that the isoflavone aglycone genistein penetrates significantly better into the skin when it is formulated in a liposmal preparation. The corresponding isoflavone glycoside genistin is not hydrolyzed to the biologically active aglycones upon topical application.

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