Molecular photoprotection of human keratinocytes in vitro by the naturally occurring mycosporine-like amino acid palythine

Abstract

SummaryBackgroundSolar ultraviolet radiation (UVR) induces molecular and genetic changes in the skin, which result in skin cancer, photoageing and photosensitivity disorders. The use of sunscreens is advocated to prevent such photodamage; however, most formulations contain organic and inorganic UVR filters that are nonbiodegradable and can damage fragile marine ecosystems. Mycosporine‐like amino acids (MAAs) are natural UVR‐absorbing compounds that have evolved in marine species for protection against chronic UVR exposure in shallow‐water habitats.ObjectivesTo determine if palythine, a photostable model MAA, could offer protection against a range of UVR‐induced damage biomarkers that are important in skin cancer and photoageing.MethodsHaCaT human keratinocytes were used to assess the photoprotective potential of palythine using a number of end points including cell viability, DNA damage (nonspecific, cyclobutane pyrimidine dimers and oxidatively generated damage), gene expression changes (linked to inflammation, photoageing and oxidative stress) and oxidative stress. The antioxidant mechanism was investigated using chemical quenching and Nrf2 pathway activation assays.ResultsPalythine offered statistically significant protection (P < 0·005) against all end points tested even at extremely low concentrations (0·3% w/v). Additionally, palythine was found to be a potent antioxidant, reducing oxidatively generated stress, even when added after exposure.ConclusionsPalythine is an extremely effective multifunctional photoprotective molecule in vitro that has potential to be developed as a natural and biocompatible alternative to currently approved UVR filters.

Photoprotection and Skin Pigmentation: Melanin-Related Molecules and Some Other New Agents Obtained from Natural Sources

“…These molecules show high photostability and strong UV-absorption, centered in the UVA-blue light range, from around 310-360 nm [96] that have evolved for protection against chronic sunlight exposure. Recent data indicate that very low concentrations of palythine show a significant protection to human keratinocytes submitted to UVA irradiation [97]. In addition, palythine behaves as a potent antioxidant, reducing oxidative stress by scavenging ROS species.…”

A Randomized Study to Determine the Sun Protection Factor of Natural Pterostilbene from Pterocarpus Marsupium

“…An ideal sunscreen should be safe, inert, non-toxic, photostable, and should be able to protect the skin from both UVA and UVB radiations [18]. Some of the natural photo protectants include aloe vera, pomegranate, tomato, green tea extracts, as well as the oils from soybean, olive, coconut, almond, and jojoba [19] and other natural protectants include the mycosporine-like amino acids (MAA) palythine, porphyra-334, shinorine, tanshinone, and licochalcone [20][21][22][23][24]. The most important biological activities in protection against sun include filtering the UVA and UVB radiations, antioxidant activity, anti-mutagenic activity, and anti-inflammatory activity [25].…”

Mycosporine-like amino acids: does Nature make a better sunscreen?

“…The current issue of the BJD features a report by Lawrence et al ., which demonstrates that palythine, a naturally occurring mycosporine‐like amino acid (MAA), found in marine organisms, provides considerable photoprotection in human epidermal keratinocytes against a variety of UVR‐induced toxic end points, including DNA damage . This effect appears to be via a number of mechanisms, which include acting as a UVR filter, a direct antioxidant and/or free radical scavenging effect and inhibition of the expression of genes associated with inflammation/immune regulation and photoageing.…”