Topical Application of Phlorotannins from Brown Seaweed Mitigates Radiation Dermatitis in a Mouse Model

Abstract

Radiation dermatitis (RD) is one of the most common side effects of radiotherapy; its symptoms progress from erythema to dry and moist desquamation, leading to the deterioration of the patients’ quality of life. Active metabolites in brown seaweed, including phlorotannins (PTNs), show anti-inflammatory activities; however, their medical use is limited. Here, we investigated the effects of PTNs in a mouse model of RD in vivo. X-rays (36 Gy) were delivered in three fractions to the hind legs of BALB/c mice. Macroscopic RD scoring revealed that PTNs significantly mitigated RD compared with the vehicle control. Histopathological analyses of skin tissues revealed that PTNs decreased epidermal and dermal thickness compared with the vehicle control. Western blotting indicated that PTNs augmented nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathway activation but attenuated radiation-induced NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and inflammasome activation, suggesting the mitigation of acute inflammation in irradiated mouse skin. PTNs also facilitated fast recovery, as indicated by increased aquaporin 3 expression and decreased γH2AX (histone family member X) expression. Our results indicate that topical PTN application may alleviate RD symptoms by suppressing oxidative stress and inflammatory signaling and by promoting the healing process. Therefore, PTNs may show great potential as cosmeceuticals for patients with cancer suffering from radiation-induced inflammatory side effects such as RD.

Seaweeds Compounds: An Ecosustainable Source of Cosmetic Ingredients?

“…These compounds attracted a lot of attention due to the multiple activities they present. Between their clinical and cosmeceutical potential antioxidant, anti-inflammatory, antitumor, antiallergic, hyaluronidase inhibitory, and matrix metalloproteinases inhibitory activities can be counted [54,57]. In addition, as explored before, they show activity not only for UV protection, but also against ionizing radiation.…”

“…Phlorotannins are oligomeric or polymeric phloroglucinol phenols, found on the algal cell wall, that are involved in the protection of cells from UV radiation [54]. From a biosynthesis perspective, the oligomeric form, phloroglucinol-which is exclusive of brown seaweed-is formed through the acetate-malonate pathway in the Golgi apparatus.…”

“…In addition, as explored before, they show activity not only for UV protection, but also against ionizing radiation. The mechanism responsible for this is the redox activity, which balances the oxidative stress within the cell and reduces the DNA damages [54,[58][59][60]. These characteristics allows the phlorotaninns to modulate the NRF2 pathway, which is linked to both, inflammatory and oxidative stress responses, being an effective natural compound capable of managing inflammatory skin diseases [54,61].…”

Aquatic Phlorotannins and Human Health: Bioavailability, Toxicity, and Future Prospects

“…Phlorotannins were also shown to promote wound healing by suppressing oxidative stress and inflammatory signaling in experimentally induced radiation dermatitis in rats. 117 Also, phlorotannins from Halidrys siliquosa showed photo-protective and antibacterial activities in vitro, 154 highlighting their potential benefits in cosmeceutical formulations.…”

Pioneering Role of Marine Macroalgae in Cosmeceuticals

“…which make it very attractive to cosmetic and cosmeceutical products. Phlorotannin has more attention in cosmetic applications due to multiple benefits in cosmetics such as antioxidant, antiinflammatory, anti-allergic, hyaluronidase inhibitor, and MMP (matrix metalloproteinase) inhibition [173]. In addition, it shows protection against damaging UV rays, but also gives protection against ionizing radiations [174].…”