Hovenia dulcis Thunb. Fruit Extract Attenuates Psoriatic Skin Inflammation in Tumor Necrosis Factor-α-Stimulated Human Keratinocyte HaCaT Cells In Vitro

Hovenia dulcis Thunb. fruit (HDF) is traditionally used for treating liver diseases and alcohol poisoning. The purpose of this study was to explore the effects of HDF on hyperproliferation, levels of inflammatory cytokines, and signaling mechanisms in human psoriatic keratinocyte HaCaT cells. HDF showed a preventive effect on tumor necrosis factor-α (TNF-α)-induced abnormal proliferation of psoriatic keratinocytes. Furthermore, real-time reverse transcription-PCR analysis showed that HDF suppressed the expressions of inflammatory cytokines; interleukin (IL)-1α and IL-1β and chemokines; CCL-20 and CXCL-8 in TNF-α-induced HaCaT cells. Western blotting revealed that HDF suppressed the levels of phosphorylated IκB and STAT3 together with a decline in the levels of phosphorylated mitogen-activated protein kinases (MAPKs). These outcomes indicate that HDF prevents the abnormal proliferation of keratinocytes and modulates inflammatory responses by suppressing nuclear factor-κB (NF-κB) and STAT3 activation through downregulation of the MAPK signaling pathway in TNF-α-induced psoriatic keratinocytes. Our study demonstrates that HDF is prospective and beneficial for psoriatic skin inflammation.

Hovenia dulcis Thumberg: Phytochemistry, Pharmacology, Toxicology and Regulatory Framework for Its Use in the European Union

Hovenia dulcis Thunberg is an herbal plant, belonging to the Rhamnaceae family, widespread in west Asia, USA, Australia and New Zealand, but still almost unknown in Western countries. H. dulcis has been described to possess several pharmacological properties, such as antidiabetic, anticancer, antioxidant, anti-inflammatory and hepatoprotective, especially in the hangover treatment, validating its use as an herbal remedy in the Chinese Traditional Medicine. These biological properties are related to a variety of secondary metabolites synthesized by the different plant parts. Root, bark and leaves are rich of dammarane-type triterpene saponins; dihydrokaempferol, quercetin, 3,3′,5′,5,7-pentahydroflavone and dihydromyricetin are flavonoids isolated from the seeds; fruits contain mainly dihydroflavonols, such as dihydromyricetin (or ampelopsin) and hovenodulinol, and flavonols such as myricetin and gallocatechin; alkaloids were found in root, barks (frangulanin) and seeds (perlolyrin), and organic acids (vanillic and ferulic) in hot water extract from seeds. Finally, peduncles have plenty of polysaccharides which justify the use as a food supplement. The aim of this work is to review the whole scientific production, with special focus on the last decade, in order to update phytochemistry, biological activities, nutritional properties, toxicological aspect and regulatory classification of H. dulcis extracts for its use in the European Union.