Investigating Birch Bark Oil Anti-Oxidative Properties in Human Keratinocytes

Abstract

ID 14365 Poster Board 355 Background: Inflammatory skin diseases like eczema and psoriasis are common irritating ailments for which there are few effective treatments. Anecdotal stories from the Indigenous L'nu in Cape Breton, NS, Canada suggest that their traditional birch bark oil (BBO) mixture, known as "maskwiomin," demonstrates potential therapeutic effects for the treatment of inflammatory skin diseases. We hypothesize that the mechanisms contributing to the possible beneficial effects of BBO involve anti-oxidant properties, which would ultimately reduce inflammation.Objective: To determine if BBO protects human keratinocytes against oxidative stimuli. Methods and Results:HaCaT human keratinocytes were treated with control cell media, 0.005% v/v BBO, or its vehicle 0.045% v/v dimethyl sulfoxide (DMSO) for 2 or 3 days, followed by 24 h treatment with the oxidative stimulus hydrogen peroxide (H 2 O 2 , 0-3528 mM). MTT assays were performed to quantify subsequent percent cell viability. BBO treatment for 3 days significantly reduced H 2 O 2 -mediated cell death (IC 50 , 3395 ± 205.0 mM) versus DMSO (2729 ± 114.8 mM) and control (2757 ± 113.7 mM). Similar results were observed with BBO treatment after 2 days. Following this, media pre-treatments were repeated for 3 days, with subsequent ROS probe CM-DCFH-DA and H 2 O 2 (588-3528 mM) 1 h treatment. Cytosolic ROS was quantified at lex 485/lem 530 nm. Compared to control and DMSO, BBO-treated cells produced no significant change in the production of ROS. Finally, BBO was tested for the presence of endotoxins, and was found to be below 0.01 EU/mL, which is considered to be endotoxin-free.Conclusions: BBO is endotoxin-free and protects human keratinocytes against the oxidative stimulus H 2 O 2 . However, this effect was not due to a reduction in cytosolic ROS levels. Further experiments are needed to determine the cytoprotective effects including investigation of BBO on mitochondrial ROS. Overproduction of ROS is involved in the pathogenesis of eczema and psoriasis, so it will be important to understand if BBO can mitigate these effects to potentially be used in therapeutic application.