Synthesis and Anti-Inflammatory Activity of Ferulic Acid-Sesquiterpene Lactone Hybrids

Abstract

Acute lung injury (ALI) is a respiratory failure disease associated with high mortality rates in patients. The primary pathological damage is attributed to the excessive release of pro-inflammatory mediators in pulmonary tissue. However, specific therapy for ALI has not been developed. In this study, a series of novel ferulic acid-parthenolide (FA-PTL) and ferulic acid-micheliolide (FA-MCL) hybrid derivatives were designed, synthesized, and evaluated for their anti-inflammatory activities in vitro. Compounds 2, 4, and 6 showed pronounced anti-inflammatory activity against LPS-induced expression of pro-inflammatory cytokines in vitro. Importantly, compound 6 displayed good water solubility, and treatment of mice with compound 6 (10 mg/kg) significantly prevented weight loss and ameliorated inflammatory cell infiltration and edema in lung tissue, as well as improving the alveolar structure. These results suggest that compound 6 (((1aR,7aS,8R,10aS,10bS,E)-8-((dimethylamino)methyl)-1a-methyl-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-decahydrooxireno[2',3':9,10]cyclodeca[1,2-b]furan-5-yl)methyl (E)-3-(4-hydroxy-3-methoxyphenyl)acrylate 2-hydroxypropane-1,2,3-tricarboxylate) might be considered as a lead compound for further evaluation as a potential anti-ALI agent.

Keywords: acute lung injury; anti-inflammatory activity; ferulic acid; micheliolide; parthenolide.

Figure 1

FA, PTL, MCL and their derivatives.

Scheme 1

Synthesis of compounds 1 and 5.

Scheme 2

Synthesis of compounds 4 and 6.

Figure 2

Anti-inflammation of 1–6 in RAW264.7 Cells. Expression of proinflammatory cytokines in RAW264.7 cells use RT-PCR. Cells (1 × 10⁶ cells/well) were seeded into 6-well plates and then pro-treated with 1–6 for 2 h. Cells were then challenged with LPS (1 μg/mL) or medium alone for 6 h and Total RNA was extracted from cells with Trizol reagent. TNF-α: tumor necrosis factor-α; IL-1β:Interleukin-1β; L-6: Interleukin-6. Data were analyzed by One-Way ANOVA. *: p < 0.05; **: p < 0.01. ns: no significance.

Figure 3

Protein levels of pro-inflammatory RAW264.7 Cells. RAW 264.7 cells were seeded into 12-well plates and then pro-treated with 6 for 6 h. Cells were then stimulated with LPS for 24 h. After 24 h incubation, the supernatant were collected and stored at −20 °C. The levels of TNF-α and IL-1β in the supernate were measured using the ELISA kit according to the manufacturer’s instructions. (Left,middle) pictures show the protein levels of TNF-α and IL-1β. (Right) picture shows the structure of compound 6. Data were analyzed using One-Way ANOVA. **: p < 0.01. ns: no significance.

Figure 4

Effect of compound 6 on body weight and survival after bleomycin-induced acute lung injury in mice. After bleomycin (4 mg/kg, 25 μL), mice were treated (i.p) daily with compound 6 (10 mg/kg, 100 μL) for 14 days. Body weight variations ((A), n = 12) and percentage (%) of mouse survival ((B), n = 5–12) were compared between the four groups. (Values are means ± SEM, ** p < 0.01).

Figure 5

Pathological image of the protective effect of compound 6 on the ALI mice. Pathological image (×2, ×20) observation of mouse lung tissue sections stained with HE.

Figure 6

The stability of compound 6 in pH7.4 HEPES buffer.