Scalp condition improvement with botanical extracts possessing chemical and physical antioxidant activity

Abstract Objective Oxidative stress is implicated in scalp and hair health manifesting in several ways, including skin barrier, hair retention, healthy hair appearance and scalp sensation. We previously linked markers of oxidative damage to dandruff and skin barrier impairment and have linked key anti‐dandruff technologies to the resolution of these issues. Here we expand the therapeutic space demonstrating many botanical extracts offer protective benefits against ROS stress via both chemical and biological antioxidant mechanisms. Methods Chemical antioxidant activity of 10 botanical extracts was measured using oxygen radical absorbance capacity (ORAC) and biological antioxidant activity was measured using a Nrf‐2 cell assay. A three‐dimensional human keratinocyte skin equivalent model from MatTek was used to measure efficacy of reducing reactive oxygen species (ROS) from both the botanicals added as a solution and from a shampoo product. A 4‐week consumer study with 56 panels was conducted with a leave‐on treatment containing a botanical extract. Measurement of the oxidized lipids (9 and 13‐Hydroxy‐10E 12Z‐octadecadienoic acid, HODE) extracted from scalp tape strips was made using gradient reversed‐phase high‐performance liquid chromatography with tandem mass spectrometry (HPLC/MS/MS). Results We demonstrated in vitro that many botanical extracts exert antioxidant activity by quenching radicals in ORAC testing as well as activating biological antioxidant pathways via nrf‐2 up‐regulation in a cellular reporter system. Furthermore, we demonstrate these antioxidant activities for these botanicals in 3D skin models and ultimately show the reduction of lipid oxidation products in a consumer use context with a rosemary extract. Conclusion Improved scalp condition can be achieved with incorporation of botanicals having the potential to exert antioxidant activity in hair/scalp care products.