How does Fern Extract (Polypodium Leucotomos) aka Heliocare protect the skin?
Extracts from the leaves of a certain species of fern, Polypodium leucotomos (PL) have been shown in clinical studies to effectively block ultraviolet (UV)-induced skin phototoxicity.
In one study, 53 patients with sun allergy condition (Idiopathic photodermatoses), consumed 480 mg PL extract daily while exposing themselves to sunlight. Over 73% of the patients had a benefit from the administered PL, with the significant reduction of skin reaction or irritation and subjective symptoms. With no side effects observed, the study authors concluded that oral supplementation with PL effectively and safely provides photoprotection.
Another clinical trial found that oral PL effectively reduced skin reddening induced by artificial UVR. Moreover, upon histological examination of skin biopsies taken from the subjects who consumed PL extract, decreased skin cell DNA damage and immune activation was noted. The authors of this study concluded that "oral administration of PL is an effective systemic chemophotoprotective agent leading to significant protection of skin against UV radiation".
PL extract appears to be especially effective in those whose skin is particularly sensitive to the sun. Several studies have found that oral PL blunts dermal allergic responses to sun exposure in those prone to such reactions
A recently published comprehensive review, by Gonzalez et al. (2010), of the mechanisms by which PL combats photoaging sates, the following:
"PL is a natural mixture of phytochemicals endowed with powerful antioxidant properties. Its short-term effects include inhibition of reactive oxygen species production induced by UV radiation, DNA damage, isomerization and decomposition of trans-urocanic acid [an endogenous sunscreen-like agent], prevention of UV-mediated apoptosis and necrosis, as well as degradative matrix remodeling which is the main cause of photoaging. These short-term effects translate into long-term prevention of photoaging and photocarcinogenesis. A striking property is that PL can exert its effect when administered orally. Together, these effects postulate PL as a natural photoprotective agent and a potential adjuvant to phototherapy for various skin diseases."
In addition, a recent animal model elucidated further mechanisms by which PL guards against photo-damages. This experiment found that PL dramatically reduced the sun-induced expression of COX-2, which drives inflammation and contributes to skin cancer growth, while it simultaneously increased the expression of a major DNA repair protein, P53. In animals fed PL, UVR exposure induced 25% fewer DNA mutations than in animals receiving a control diet.