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Sheldon R Pinnell

Publications and source records attributed to Sheldon R Pinnell.

7 recordsLinked to original sources
PubMed2005

Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin.

Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15%l-ascorbic acid and 1%alpha-tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.

Animals↗
PubMed2003

Cutaneous photodamage, oxidative stress, and topical antioxidant protection.

UNLABELLED: New methods to protect skin from photodamage from sun exposure are necessary if we are to conquer skin cancer and photoaging. Sunscreens are useful, but their protection is not ideal because of inadequate use, incomplete spectral protection, and toxicity. Skin naturally uses antioxidants (AOs) to protect itself from photodamage. This scientific review summarizes what is known about how photodamage occurs; why sunscreens--the current gold standard of photoprotection--are inadequate; and how topical AOs help protect against skin cancer and photoaging changes. This review is intended to be a reference source, including pertinent comprehensive reviews whenever available. Although not all AOs are included, an attempt has been made to select those AOs for which sufficient information is available to document their potential topical uses and benefits. Reviewed are the following physiologic and plant AOs: vitamin C, vitamin E, selenium, zinc, silymarin, soy isoflavones, and tea polyphenols. Their topical use may favorably supplement sunscreen protection and provide additional anticarcinogenic protection. (J Am Acad Dermatol 2003;48:1-19.) LEARNING OBJECTIVE: At the completion of this learning activity, participants should have an understanding of current information about how the sun damages skin to produce skin cancer and photoaging changes, how the skin naturally protects itself from the sun, the shortcomings of sunscreens, and the added advantages of topical AOs for photoprotection.

Antioxidants↗
PubMed2003

UV photoprotection by combination topical antioxidants vitamin C and vitamin E.

BACKGROUND: Virtually all plants and animals protect themselves from the sun using vitamins C and E. OBJECTIVE: The purpose of this study was to see if a combination of topical vitamins C and E is better for UV protection to skin than an equivalent concentration of topical vitamin C or E alone. METHODS: We developed a stable aqueous solution of 15% L-ascorbic acid (vitamin C) and 1% alpha-tocopherol (vitamin E). We applied antioxidant or vehicle solutions to pig skin daily for 4 days. We irradiated (1-5x minimal erythema dose) control- and antioxidant-treated skin using a solar simulator with a 295-nm band-pass filter. On day 5, we measured antioxidant protection factor, erythema, sunburn cells, and thymine dimers. RESULTS: The combination of 15% L-ascorbic acid and 1% alpha-tocopherol provided significant protection against erythema and sunburn cell formation; either L-ascorbic acid or 1% alpha-tocopherol alone also was protective but the combination was superior. Application during 4 days provided progressive protection that yielded an antioxidant protection factor of 4-fold. In addition, the combination of vitamins C and E provided protection against thymine dimer formation. CONCLUSION: Appreciable photoprotection can be obtained from the combination of topical vitamins C and E. We suggest that these natural products may protect against skin cancer and photoaging.

Animals↗
PubMed2002

Evidence supporting zinc as an important antioxidant for skin.

Antioxidants play a critical role in keeping skin healthy. The antioxidant benefits of vitamin C and E are well known, but the importance of the trace mineral, zinc, has been overlooked. This article reviews the evidence supporting zinc's antioxidant role in protecting against free radical-induced oxidative damage. Zinc protects against UV radiation, enhances wound healing, contributes to immune and neuropsychiatric functions, and decreases the relative risk of cancer and cardiovascular disease. All body tissues contain zinc; in skin, it is five to six times more concentrated in the epidermis than the dermis. Zinc is required for the normal growth, development and function of mammals. It is an essential element of more than 200 metalloenzymes, including the antioxidant enzyme, superoxide dismutase, and affects their conformity, stability, and activity. Zinc also is important for the proper functioning of the immune system, and for glandular, reproductive and cell health. Abundant evidence demonstrates the antioxidant role of zinc. Topical zinc, in the form of divalent zinc ions, has been reported to provide antioxidant photoprotection for skin. Two antioxidant mechanisms have been proposed for zinc: zinc ions may replace redox active molecules, such as iron and copper, at critical sites in cell membranes and proteins; alternatively, zinc ions may induce the synthesis of metallothionein, sulfhydryl-rich proteins that protect against free radicals. No matter how they work, topical zinc ions may provide an important and helpful antioxidant defense for skin.

Antioxidants↗