Protection of Photosensitized Rats against Long Ultraviolet Radiation by Topical Application of Compounds with Structures Similar to That of Dihydroxyacetone

Abstract

Dihydroxyacetone (DHA), a browning agent, protects photosensitive rats and humans against long ultraviolet radiation (UVA, 320–400 nm) and visible (blue) light. The photoprotective efficacy of DHA and structurally similar compounds was assessed as prevention of edema in the paws of psoralen-sensitized rats, after exposure to blacklight fluorescent lamps. Methylglyoxal produced a yellow-brown color and provided nearly the same protection as DHA, whereas monohydroxyacetone did not color the skin and afforded little or no protection. Glyceraldehyde provided a moderate amount of protection, which was enhanced by prior exposure of the agent to alkaline pH. A solution of 5-hydroxymethylfurfuraldehyde was yellow and provided minimal protection by staining the skin rather than browning it. We conclude that the ability to produce a brown color in skin is a useful criterion for screening compounds for photoprotective efficacy against UVA radiation.

Dihydroxyacetone Test as a Substitute for the Dansyl Chloride Test

“…It has been claimed that DIIA produces a substantive color that resists even soap-and-watcr bathing [20], with which our data are at variance. Soaps and other cleansing agents may remove, at least in part, melanoids which are probably not all tightly bound to the stratum corneum.…”

“…Soaps and other cleansing agents may remove, at least in part, melanoids which are probably not all tightly bound to the stratum corneum. The UVA protection by DHA [20][21][22] should be viewed with such a limitation.…”

Sunscreens: Progress and Perspectives on Photoprotection of Human Skin against UVB and UVA Radiation

“…There is one additional way to protect the skin against UVA radiation. It involves the use of dihydroxyacetone (DHA at about 3-5% concentration) in sunless tanning lotion form, usually at low alkaline pH (19). The newly modified lotions of DHA manufactured by leading sunscreen companies are also enriched with a UVB absorbing chemical sunscreen (e.g., octylmethoxy cinnamate, octylsalicylate, or Padimate-O) to provide broad-spectrum protection against UVB and UVA radiation.…”

“…Many fairskinned people who like the skin to be tanned with golden-brown color but worry about the effects of sunlight, like such artificially induced skin tanning reaction without undergoing the harmful effects of sun exposure; people learn to acquire esthetically pleasing color of their skin that is photoprotective against UVA radiation also. Patients who are sensitive to tNA radiation (e.g., patients with PMLE, or erythropoietic protoporphyria or patients with albinism) can be helped and protected by such formulations (19).…”

Broad-Spectrum Photoprotection: The Roles of Tinted Auto Windows, Sunscreens and Browning Agents in the Diagnosis and Treatment of Photosensitivity

“…To our knowledge, the absorption spectrum of the brown skin pigment produced by DHA has not been pub lished. We have cited experimental and clinical evidence [4,5] that the coloration protects against long UVA and visible (blue) radiation. Such an absorber may be called a UVA/V screen.…”