The Role of Andrographolide on Skin Inflammations and Modulation of Skin Barrier Functions in Human Keratinocyte

Abstract

Andrographolide (AG) is a bioactive natural occurring compound found in a medicinal plant called Andrographis paniculata. AG is highly bioavailable and well-known for anti-cancer, antioxidant, anti-inflammatory, and many other bio-functional activities. Hence, its anti-inflammatory effects in keratinocytes have not been studied. The skin inflammations and disruptions on skin permeabilities by cell-mediated inflammatory cytokines lead to chronic inflammatory skin diseases such as allergies, atopic dermatitis, psoriasis, and so on. We have investigated cell viability for evaluating cytotoxicity. Moreover, tumor necrosis factor (TNF)-α, interleukin (IL)-1B, IL-6, and prostaglandin E2 levels have been measured by enzyme-linked immunosorbent assay. The effect of AG on nuclear factor kappa B(NF-κB) signaling pathways and inducible nitric oxide synthase and cyclooxygenase-2 expressions have been carried out by western blot analysis. c-Fos presence has been elucidated by confocal microscopy. Furthermore, the skin barrier functions of AG have been investigated in HaCaT cell. AG significantly restored skin barrier functions and reduced inflammation in LPS or TNF-α/IFN-γ stimulated HaCaT cells by preventing NF-κB, c-Fos activation, and modulating filaggrin, involucrin, and loricrin expressions. These results potentially proved that AG could be used as a therapeutic agent against inflammatory skin diseases.