Oral Polypodium Leucotomos Extract and Its Impact on Visible Light-Induced Pigmentation in Human Subjects
December 2019 | Volume 18 | Issue 12 | Original Article | 1198 | Copyright © December 2019
Tasneem F. Mohammad MD,a Indermeet Kohli PhD,b Cynthia L. Nicholson MD,b German Treyger DO,c Suteeraporn Chaowattanapanit MD,d Amanda F. Nahhas DO,e Taylor L. Braunberger MD,aHenry W. Lim MD,f Iltefat H. Hamzavi MDf
bDepartment of Dermatology, Wayne State University, Detroit, MI
cDepartment of Dermatology, Beaumont Hospital, Trenton, MI
dDepartment of Medicine, Srinagarind Hospital, Khon Kaen, Thailand
eDepartment of Dermatology, Beaumont-Farmington Hills, Farmington Hills, MI
BACKGROUND: Visible light (VL) has multiple effects on the skin that currently available sunscreens do not protect against. Polypodium leucotomos extract (PLE) has properties that may offer protection against VL.
OBJECTIVES: To determine the effectiveness of PLE in preventing VL-induced effects.
METHODS: Twenty-two subjects with Fitzpatrick skin phototype IV-VI were enrolled. On day 0, subjects were irradiated with VL. Clinical Investigator’s Global Assessment (IGA) scoring and spectroscopic evaluations were performed immediately, 24 hours, and 7 days after irradiation. Subjects then received a 28-day supply of PLE (480 mg daily). Irradiation and evaluation were repeated. Three 4-mm punch biopsies were obtained for immunohistochemistry analysis: one from normal unirradiated skin and the other two twenty-four hours after irradiation, pre- and post-PLE, from sites irradiated with highest dose of VL.
RESULTS: All subjects had immediate pigment darkening, persistent pigment darkening, and delayed tanning both pre- and post-PLE. For the highest VL dose (480 J/cm²) spectroscopic assessments demonstrated a statistically significant decrease in persistent pigment darkening and delayed tanning post-PLE. In addition, there was a significant decrease in cyclooxygenase-2, and a trend towards decreases in the markers for cellular damage post-PLE. While there was a trend towards lower IGA scores post-PLE, statistical significance was not reached possibly due to lack of sensitivity of the visual IGA scoring system in detecting small changes.
CONCLUSIONS: Spectroscopic data and immunohistochemistry indicate an effect of PLE on visible light induced effects. As such, PLE may be used as an adjuvant to traditional means of photoprotection to protect against the effects of VL.
Clinical trial registration number: NCT02904798.J Drugs Dermatol. 2019;18(12):1198-1203.
Approximately 44% of sunlight is composed of visible light (VL).1 VL has been shown to have multiple biologic effects on the skin 2 including DNA damage secondary to the production of reactive oxygen species (ROS), the induction of pro-inflammatory cytokines,3 worsening of photo-exacerbated conditions,4 and pigmentation in melano- competent individuals.5,6 Pigmentation caused by VL occurs in 3 stages.6 The first, immediate pigment darkening (IPD), occurs immediately after exposure and can last up to 2 hours. IPD is followed by persistent pigment darkening (PPD), which occurs between 2 to 24 hours after exposure. Both IPD and PPD are caused by the oxidation and redistribution of existing melanin in the skin.The final stage is delayed tanning (DT), which occurs 24 hours to several days after exposure and is caused by the new production of melanin.6
Disorders of pigmentation such as melasma and post-inflammatory hyperpigmentation are relatively common in those with skin of color. Affected individuals often note worsening of cutaneous hyperpigmentation after sun exposure despite appropriate application of broad- spectrum sunscreens. This is in part because currently available organic sunscreens and micronized inorganic sunscreens primarily protect against ultraviolet (UV) radiation, but are ineffective against VL.4 Iron oxides, which are present in make-up and tinted products, are effective against VL. However, many people are resistant to the idea of wearing “make-up” for photoprotection. They are also not water or sweat resistant. Taken together, alternative, and supplementary methods of protection against VL induced effects, such as oral antioxidants, are necessary.