Hoveniae Semen Seu Fructus Ethanol Extract Exhibits Anti-Inflammatory Activity via MAPK, AP-1, and STAT Signaling Pathways in LPS-Stimulated RAW 264.7 and Mouse Peritoneal Macrophages

Abstract

Hoveniae semen seu fructus (HSF, fruit and seed of Hovenia dulcis Thunb) is an important traditional herbal medicine and food supplement in East Asia for the treatment of liver diseases, alcohol poisoning, obesity, allergy, and cancer. HSF has also been reported to have anti-inflammatory activity, but the cellular mechanism of action is not fully understood. We assessed the anti-inflammatory properties of an HSF ethanol (HSFE) extract and explored its precise mechanism. The ability of HSFE to suppress inflammatory responses was investigated in a murine macrophage cell line, RAW 264.7, and mouse primary macrophages. Secretions of NO, proinflammatory cytokines, inflammatory factors, and related proteins were measured using the Griess assay, ELISA, Western blot analysis, and real-time PCR, respectively. In addition, the main components of HSFE were analyzed by HPLC, and their anti-inflammatory activity was confirmed. Our results showed that pretreatment of HSFE markedly reduced the expression of NO and iNOS without causing cytotoxicity and significantly attenuated secretion of proinflammatory cytokines, including TNF-α, IL-6, and IL-1β. In addition, HSFE strongly suppressed phosphorylation of MAPK and decreased the activation of AP-1, JAK2/STAT, and NF-κB in LPS-stimulated RAW 264.7 cells in a concentration-dependent manner. Furthermore, HSFE strongly suppressed the inflammatory cytokine levels in mouse peritoneal macrophages. Also, as a result of HPLC analysis, three main components, ampelopsin, taxifolin, and myricetin, were identified in the HSFE extract, and each compound effectively inhibited the secretion of inflammatory mediators induced by LPS. These findings show that HSFE exerts anti-inflammatory effects by suppressing the activation of MAPK, AP-1, JAK2/STAT, and NF-κB signaling pathways in LPS-stimulated macrophages. In addition, the anti-inflammatory efficacy of HSFE appears to be closely related to the action of the three main components. Therefore, HSFE appears to be a promising candidate for the treatment of inflammatory diseases.

Anti-Inflammatory Activity and ROS Regulation Effect of Sinapaldehyde in LPS-Stimulated RAW 264.7 Macrophages

“…Macrophages exposed to LPS during microorganism infections stimulate the immune system to produce cytokines and chemokines, followed by inflammatory events. Thus, inhibiting macrophage activation by LPS is an important focus for therapeutic strategies aimed at treating inflammatory diseases [ 11 , 12 , 13 , 14 ].…”

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

“…Different studies reported above highlighted the anti-inflammatory activity of H. dulcis extracts explicated through the inhibition of pathway and mediators known to be crucial for the development of inflammatory reaction, such as NFKB, TNF-α, IL-1, IL-10, etc. [ 48 , 49 , 67 , 68 ]. The anti-inflammatory effect of H. dulcis fruits ethanol extract in a mouse macrophage RAW 276.7 cells model was investigated.…”

“…Results showed that H. dulcis extract significantly inhibited, in a dose-dependent manner, the expression of NO, nitric oxide synthase, COX-2, interleukin-1b, TNF-α, the nuclear translocation of NF-kB, p65 and the phosphorylation of IkB in the cytoplasm [ 67 ]. A similar in vitro study conducted by Jeong et al [ 48 ] assessed the anti-inflammatory effect and the mechanism of action of Hoveniae semen seu fructus extracts in the murine macrophage cell line (RAW 264.7) and mouse primary macrophages. They demonstrated that H. dulcis ethanol extract (10, 30 and 50 mg/mL) strongly inhibited, in a concentration-dependent manner, the phosphorylation of MAPK and reduced the activation of activator protein-1 (AP-1), janus kinase-2 (JAK2)/STAT and NF-κB in LPS-stimulated RAW 264.7 cells.…”

“…In further analyses, DHM, taxifolin and myricetin were identified as the bioactive molecules responsible for the anti-inflammatory effect of the extract. In fact, each compound inhibited the inflammatory response in LPS-stimulated macrophages [ 48 ]. The anti-inflammatory action of H. dulcis extract was also confirmed in an in vivo model of atopic dermatitis-like skin lesions induced by 2,4-dinitrochlorobenzene (DNCB) in NC/Nga mice and TNF-α/interferon (IFN) gamma-induced chemokines production in spontaneously immortalized human keratinocytes (HaCaT) cell lines.…”

Anti-Inflammatory Activity of Extracts and Pure Compounds Derived from Plants via Modulation of Signaling Pathways, Especially PI3K/AKT in Macrophages

“…AP-1 is a mediator of M1 macrophage polarization [ 93 ]. That transcription factor is a target for Persicaria chinensis and Hovenia dulcis extracts in a study conducted on RAW264.7 cells [ 94 , 95 ]. AP-1 protein is also downregulated in LPS-activated RAW 264.7 macrophages by patriscabrin F, an iridoid obtained from Patrinia scabra [ 75 ], koreanaside A, a lignan isolated from the Forsythia koreana [ 76 ] and torilin, a sesquiterpene from Torilis japonica [ 96 ].…”