1 November 2005 Protection Against Photoaging in the Hairless Mouse by the Isoflavone Equol
Vivienne E. Reeve, Sitarina Widyarini, Diane Domanski, Elaine Chew, Karen Barnes
Author Affiliations +

Topical application of the isoflavone equol immediately following solar-simulated UV (SSUV) radiation exposure has previously been demonstrated to have significant photoprotective effects. Equol reduced both the inflammatory edema and the systemic suppression of the contact hypersensitivity reaction in hairless mice. Furthermore, daily topical equol application immediately following irradiation during a 10-week chronic SSUV exposure regime also reduced photocarcinogenesis severity in the mouse. This study examines the potential for topical equol to prevent photoaging in response to chronic SSUV irradiation for up to 30 weeks. We did not find consistent expression of the characteristic markers of photoaging until 30 weeks, although moderate epidermal hyperplasia and a transient increase in dermal mast cell numbers were evident after 1 week. Daily application of 10 μM equol lotion significantly reduced these early changes. However after 30 weeks of SSUV exposure, photoaging was well developed, as shown histologically by markedly increased epidermal hyperplasia, increased dermal mast cell number, pronounced focal elastotic deposits, degraded dermal collagen and deposition of glycosaminoglycans in the lower dermis. Topical equol treatment protected significantly from each of these impairments, as demonstrated histologically and quantitatively. Additionally, equol was found to have strong antioxidant action against acute UVA (320–400 nm)–induced lipid peroxidation of mouse skin, this property accounting for its antiphotoaging mechanism. The evidence for equol's antiphotoaging activity, taken together with its anti-inflammatory, immunoprotective and anticarcinogenic efficacy against SSUV irradiation in the mouse, suggests that equol could be developed as a helpful topical photoprotective agent for daily use by humans.

Vivienne E. Reeve, Sitarina Widyarini, Diane Domanski, Elaine Chew, and Karen Barnes "Protection Against Photoaging in the Hairless Mouse by the Isoflavone Equol," Photochemistry and Photobiology 81(6), 1548-1553, (1 November 2005). https://doi.org/10.1562/2005-07-26-RA-624
Received: 26 July 2005; Accepted: 1 September 2005; Published: 1 November 2005

This article is only available to subscribers.
It is not available for individual sale.

Get copyright permission
Back to Top