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Author: Vanessa Ngan, Staff Writer, 2005.
Polypodium leucotomos extract (PLE) comes from a tropical fern plant grown in Central and South America. Native Americans have used the plant extract for centuries for the treatment of inflammatory disorders and skin diseases. Clinical research has shown that it has antioxidant and photoprotective properties and taken orally provides protection against the harmful effects of ultraviolet (UV) radiation from the sun and other sources.
To gain a better understanding of how polypodium leucotomos extract works, you need to understand the effects of UV radiation on the body. These are described in the article on sunburn.
The proposed mechanism of action of oral polypodium leucotomos extract is fairly complex but has been summarised into the following main points:
Polypodium leucotomos extract is an addition to the armamentarium against the damaging effects of UV radiation exposure. It should be considered as another layer of protection and used in conjunction with a good sunscreen and protective clothing.
Polypodium leucotomos extract is particularly suitable for people who are photosensitive, especially those with polymorphous light eruption. Clinical trials have been performed in people with skin types II to IV and results show that polypodium leucotomos extract provides significant protection of the skin against UV radiation.
Polypodium leucotomos extract can also be used to protect against photochemotherapy (PUVA)-induced skin phototoxicity. Extensive PUVA treatment results in premature ageing changes in the skin (increased dryness, freckling and wrinkling) and can increase the chance of skin cancer. Fair-skinned individuals or those with previous sun or radiation damage are most at risk. In clinical trials, polypodium leucotomos extract has proven to be the first oral agent effective in reducing the harmful side effects of PUVA treatment.
Polypodium leucotomos extract is marketed as a dietary supplement containing a combination of the antioxidants (Heliocare®, Antioxidine®, and others). These are rapidly absorbed and provide early protection that lasts up to 2 hours after administration, against the initial signs of sunburn (erythema). However, the photoprotective effect of polypodium leucotomos extract extends beyond just decreasing erythema. The antioxidant properties of orally administered polypodium leucotomos extract work at protecting the skin at a deeper cellular level that is not achieved with topically applied antioxidants.
Polypodium leucotomos extract has not been clinically tested in patients less than 18 years and in pregnant or breastfeeding women. Hence there is no data to support its use in these groups.
Polypodium leucotomos extract supplements have been used in Europe since the 1980s without any side effects being reported.
Polypodium leucotomos extract has not been thoroughly tested for interactions with other supplements and drugs. Some concern has been expressed that it may interact with medications that affect the function of the heart or blood pressure, as cardiac effects have been demonstrated with a related fern species, Polypodium vulgare.
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