Role of Oral Polypodium Leucotomos Extract in Dermatologic Diseases: A Review of the Literature

Polypodium leucotomos is a tropical fern of the Polypodiaceae family native to Central and South America. Polypodium leucotomos extract (PLE; Fernblock^®, Ferndale Laboratories, Ferndale, Michigan, USA) is a polyphenol-enriched natural product derived from the leaves of the Polypodium leucotomos fern, and has long been known for its anti-inflammatory and antitumor properties.^1,2 Historically, Polypodium leucotomos was first introduced in Europe after the botanical expedition of Ruiz funded by the Spanish Crown, and later spread to other areas³. Several animal and human studies have been performed in recent years that have helped elucidate PL’s mechanisms of action, which may explain its observed clinical effects of photoprotection and chemoprevention.

PLE has been used in various formulations for several years in folk medicine for treatment of a variety of inflammatory ailments including psoriasis, vitiligo, atopic dermatitis, and photosensitive disorders. Fernblock^® is currently distributed in over 26 countries including the United States and Europe. It is available as a topical gel, cream, spray, and compact makeup powder as well as a systemic agent in the form of oral capsules. PL has been available as a supplement in Europe since 2001, and as a topical product since 2000. PL has been an oral dietary supplement in the US since 2006. Currently, it is marketed as an oral dietary supplement to help "protect against sun-related effects and aging", with a recommended dose of one 240 mg capsule in the morning, and when extensive sun exposure is anticipated, to take 240 mg one hour before exposure, and another 240 mg 2-3 hours after. It is marketed as Heliocare^™ by Ferndale Healthcare, Ferndale, Michigan.

In regards to future developments, research is currently underway to explore alternative extraction processes, which could further enhance PL’s photoprotective and anti-oxidant activities both topically and orally, as well as to investigate PL’s use in combination with other agents, which could provide synergic activity. It is hoped that this research will allow for the development of targeted formulations for specific photoprotection indications, for prevention of photoaging, and as adjuvant treatment in sunlight induced or aggravated conditions such as actinic keratosis and melasma.

PLE has been used to treat a variety of dermatologic disorders including immunologically-mediated photodermatoses, vitiligo, melasma, psoriasis, and atopic dermatitis. It has also been used to minimize the development of photoaging and skin cancers, and more recently, to decrease the development of infectious disease in athletes. In this article, we will briefly discuss its mechanisms of action as well as review its use in the treatment of dermatologic diseases.

It is well documented that chronic unprotected or excessive ultraviolet (UV) radiation exposure induces a variety of damage responses on cellular and molecular levels, including the induction of stress proteins, indirect DNA damage due to reactive oxygen species and direct DNA damage due to formation of cyclobutane pyrimidine dimers; these lead to immunosuppression and carcinogenesis, impaired immune surveillance due to UV-induced decrease in epidermal Langer-