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    Soy Isoflavone

    1. Int J Mol Sci. 2010;11(12):4782-95. Epub 2010 Nov 24. Anti-photoaging effects of soy isoflavone extract (aglycone and acetylglucoside form) from soybean cake.
    Huang CC, Hsu BY, Wu NL, Tsui WH, Lin TJ, Su CC, Hung CF. School of Medicine, Fu Jen Catholic University, Taipei, Taiwan; E-Mail:

    "Soy isoflavones, found in soybean and soybean products, have been reported to possess many physiological activities such as antioxidant activity, inhibition of cancer cell proliferation, reduction of cardiovascular risk, prevention of osteoporosis and alleviation of postmenopausal syndrome. In our previous study, soy isoflavone extract ISO-1 (containing 12 soy isoflavones) from soybean cake was demonstrated to prevent skin damage caused by UVB exposure. In this study, soy isoflavone extract from soybean cake was further purified and evaluated for the protective effects on UVB-induced damage. The results revealed that Fraction 3, which contains the aglycone group (daidzein, genistein and glycitein) and acetylglucoside group (acetyldaidzin, acetylgenistin and acetylglycitin) of soy isoflavones, could inhibit UVB-induced death of human keratinocytes and reduce the level of desquamation, transepidermal water loss (TEWL), erythema and epidermal thickness in mouse skin. Furthermore, topical application of Fraction 3 increased the activity of catalase and suppressed cyclooxygenase-2 (COX-2) and proliferating cell nuclear antigen (PCNA) expression in mice exposed to UVB. In addition, in comparison with ISO-1 and genistein, the Fraction 3 possessed much greater protective effects on both UVB-induced oxidative stress and keratinocyte death than other fractions. Therefore, the soy isoflavone extract Fraction 3 from soybean cake is a desirable anti-photoaging agent for skin care. PMCID: PMC3100816 PMID: 21614173 [PubMed]"

    2. Int J Pharm. 2008 Nov 19;364(1):36-44. Epub 2008 Aug 13. In vitro and in vivo evaluation of topical delivery and potential dermal use of soy isoflavones genistein and daidzein.
    Huang ZR, Hung CF, Lin YK, Fang JY. Pharmaceutics Laboratory, Graduate Institute of Natural Products, Chang Gung University, 259 Wen-Hwa 1st Road, Kweishan, Taoyuan 333, Taiwan.

    "Genistein, daidzein, and glycitein are soy isoflavones. These compounds can be used to protect the skin from oxidative stress induced by UVB radiation. To this end, the feasibility of skin absorption of soy isoflavones was evaluated in the present study. As assayed by flow cytometry, UVB-induced H(2)O(2) production in keratinocytes was inhibited by genistein and daidzein, confirming that these two compounds can act as free radical scavengers when keratinocytes are photodamaged. Glycitein showed no protective activity against photodamage. The effects of vehicles on the in vitro topical delivery from saturated solutions such as aqueous buffers and soybean oil were investigated. The isoflavones in a non-ionized form (pH 6) showed higher skin deposition compared to the ionized form (pH 10.8). Soybean oil reduced the isoflavone amount retained in the skin, especially for genistein. Genistein generally exhibited greater skin absorption than did daidzein. However, daidzein permeation was enhanced when an aglycone mixture was used as the active ingredient. An eutectic effect was proposed as the enhancing mechanism. In vivo skin deposition showed a linear correlation with the in vitro results. The safety profiles suggested no or only negligible stratum corneum disruption and skin erythema by topical application of soy isoflavones. It was concluded that topical delivery may serve as a potent route for soy isoflavones against photoaging and photodamage. PMID: 18761396 [PubMed - indexed for MEDLINE]"

    3. J Ethnopharmacol. 2009 Oct 29;126(1):108-13. Epub 2009 Aug 11. In vitro and in vivo anti-photoaging effects of an isoflavone extract from soybean cake.
    Chiu TM, Huang CC, Lin TJ, Fang JY, Wu NL, Hung CF. Department of Dermatology, Changhua Christian Hospital, Changhua Hsien, Taiwan, ROC.

    "ETHNOPHARMACOLOGICAL RELEVANCE: Soy has been used in traditional Chinese medicine for thousands of years for its health and nutritional benefits, as well as to treat and care for the skin. Advanced skin care research has shown that soy isoflavone and genistein are effective in reducing damage to the skin from the sun. AIM OF THE STUDY: To study the protective effects of isoflavone extract from soybean cake against the UVB-induced skin damage. MATERIALS AND METHODS: The in vitro effects and possible mechanisms of soybean extract on UVB protection were determined in HaCaT cells. In the in vivo study, ICR-Foxn/(nu) mice were irradiated with UVB. The epidermal thickness, catalase and the expressions of cyclooxygenase-2 (COX-2) and proliferating cell nuclear antigen (PCNA) were detected to evaluate the antioxidant and anti- inflammatory activities of the isoflavone extract. RESULTS: Our in vitro studies showed that UVB-induced HaCaT cell death and the phosphorylation of p38, JNK, and ERK1/2 decreased in the presence of isoflavone extract. In the in vivo studies, we found that the topical application of isoflavone extract before UVB irritation decreased the epidermal thickness and the expressions of COX-2 and PCNA and increased catalase concentration. These results showed anti-photoaging effect of isoflavone extract from soybean cake involved the inhibition of UVB-induced apoptosis and inflammation. CONCLUSIONS: It is shown that isoflavone extract from soybean cake may be functional cosmeceutical candidate for skin photoaging. PMID: 19679176 [PubMed - indexed for MEDLINE]"