Abstract
Uncontrolled inflammation causes health problems1. Extracellular signal-regulated kinase (ERK) phosphorylates signal transducer and activator of transcription 3 (STAT3) at Ser727, resulting in inflammation2. The leaf of Vernonia amygdalina (VA) is a medicinal herb for managing inflammation-associated diseases3. Oral administration or topical application of VA leaf extract exerts anti-inflammatory effects in rat models4-5. However, the anti-inflammatory mechanisms of the herb are not fully understood. The present study aimed to investigate the involvement of ERK/STAT3 (Ser727) signaling in the anti-inflammatory effects of an ethanolic extract of VA leaves.
Extracts of VA leaves were prepared with different concentrations of ethanol. A
LPS-stimulated RAW 264.7 cell model was used for in vitro assays, and a TPA (12-O-tetradecanoylphorbol-13-acetate)-induced ear edema mouse model was employed for in vivo assays. The 95% ethanol extract of VA leaves (VAE) exerted the strongest inhibitory effect on nitric oxide (NO) production in LPS-stimulated macrophages; thus, it was selected for use in this study. We found that topical application of VAE ameliorated mouse ear edema induced by TPA. VAE suppressed the phosphorylation of ERK (Thr202/Tyr204) and STAT3 (Ser727); and decreased protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, IL-1³ and tumor necrosis factor-α (TNF-α) in mouse ear tissues and in LPS-stimulated RAW 264.7 cells. VAE also inhibited NO production, and lowered mRNA levels of IL-6, IL-1³ and TNF-α in macrophages.
In summary, VAE ameliorates TPA-induced mouse ear edema, and suppression of
ERK/STAT3 (Ser727) signaling is involved in VAE’s anti-inflammatory effects. These novel data provide further pharmacological justifications for the medicinal use of VA in treating inflammation-associated diseases, and lay the groundwork for developing VAE into a new anti-inflammatory agent.
Extracts of VA leaves were prepared with different concentrations of ethanol. A
LPS-stimulated RAW 264.7 cell model was used for in vitro assays, and a TPA (12-O-tetradecanoylphorbol-13-acetate)-induced ear edema mouse model was employed for in vivo assays. The 95% ethanol extract of VA leaves (VAE) exerted the strongest inhibitory effect on nitric oxide (NO) production in LPS-stimulated macrophages; thus, it was selected for use in this study. We found that topical application of VAE ameliorated mouse ear edema induced by TPA. VAE suppressed the phosphorylation of ERK (Thr202/Tyr204) and STAT3 (Ser727); and decreased protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, IL-1³ and tumor necrosis factor-α (TNF-α) in mouse ear tissues and in LPS-stimulated RAW 264.7 cells. VAE also inhibited NO production, and lowered mRNA levels of IL-6, IL-1³ and TNF-α in macrophages.
In summary, VAE ameliorates TPA-induced mouse ear edema, and suppression of
ERK/STAT3 (Ser727) signaling is involved in VAE’s anti-inflammatory effects. These novel data provide further pharmacological justifications for the medicinal use of VA in treating inflammation-associated diseases, and lay the groundwork for developing VAE into a new anti-inflammatory agent.
| Original language | English |
|---|---|
| Pages | 32 |
| Number of pages | 1 |
| Publication status | Published - 19 Nov 2022 |
| Event | 第七届可食和药用植物资源及功能成分国际学术研讨会 = 7th International Symposium on Edible & Medical Plant Resources and the Bioactive Ingredients, ISEPR 2022 - Urumqi, China Duration: 19 Nov 2022 → 19 Nov 2022 http://www.xjipc.cas.cn/tzggnew/202211/t20221116_6549481.html |
Symposium
| Symposium | 第七届可食和药用植物资源及功能成分国际学术研讨会 = 7th International Symposium on Edible & Medical Plant Resources and the Bioactive Ingredients, ISEPR 2022 |
|---|---|
| Country/Territory | China |
| City | Urumqi |
| Period | 19/11/22 → 19/11/22 |
| Internet address |
User-Defined Keywords
- Acute inflammation
- TPA
- ERK
- STAT3
- Vernonia amygdalina