1135 Identification of novel derivatives of fisetin with anti-inflammatory and antioxidant activities in cutaneous keratinocytes and macrophage

Psoriasis is a chronic immune-mediated inflammatory skin disease. Sturdy genetic propensity and autoimmune pathogenic attribute, makes psoriasis difficult and costly to treat even with available FDA-approved biologics, thus the need to develop novel alternative and efficacious PS therapies. Fisetin, a polyphenolic phytonutrient with several beneficial effects like antioxidation, antiproliferation, anti-inflammatory with known in vitro and in vivo effects. Several scientific studies reports the anti-psoriasis of fisetin, but are limited in usage due to its poor lipid solubility, low bioavailability, and rapid biotransformation. In this study, we have identified novel fisetin derivatives lacking the susceptible 7-hydroxy or the 3’,4’-di-OH group on ring A and B respectively but with enhanced anti-psoriatic and anti-inflammatory properties using fluorometric techniques and in vitro skin (keratinocytes-HaCaT) and immune (macrophages-RAW 264.7) cell cultures in vitro. Compared to fisetin these derivatives show enhanced cyclooxygenase-2 (COX 2) inhibitory activity using COX-2 ELISA assay kit. Inflammation cascade spurred by nitric oxide levels and cytokines (TNF-α/IL-6) were significantly downregulated in RAW 264.7 cells stimulated with lipopolysaccharide (LPS) and interferon-gamma(INF-gamma). Western blot analysis of TNF-alpha activated HaCaT revealed a significant reduction of pAkt, p-mTOR, p-Raptor, p-GSK3β, iNOS and IL-22 responsible for molecular expression of major signaling pathway involved in PS and other inflammatory disease. Furthermore, activated-HaCaT treated with derivatives showed marked reduction in the level of Ki-67, a hyper-proliferation protein as analyzed by immunostaining. In summary, our data asserts the anti-inflammatory propensity of these novel fisetin-derivatives, and propose they could further be exploited against psoriasis and other inflammatory conditions.