Acanthoic Acid Research Articles

Inhibitory effect of TNF-alpha and IL-8 secretion by pimarane-type diterpenoids from Acanthopanax koreanum.

A new pimarane-type diterpene compound, acanthokoreoic acid A together with three known compounds, acanthoic acid, acanthol, and sumogaside were isolated from a CH(2)Cl(2) fraction of Acanthopanax koreanum by repeated column chromatography and reversed phase preparative HPLC. Acanthoic acid was isolated in high yields and showed potent inhibitory activity on the IL-8 secretion of the TNF-alpha-stimulated human colon adenocarcinoma cell line HT-29 and on the TNF-alpha secretion of the trypsin-stimulated human leukemic mast cell line HMC-1.

Enantioselective synthesis of the antiinflammatory agent (-)-acanthoic acid.

An enantioselective synthesis of the potent antiinflammatory agent (-)-acanthoic acid (1) is described. The successful strategy departs from (-)-Wieland-Miescher ketone (10), which is readily available in both enantiomeric forms and constitutes the starting point toward a fully functionalized AB ring system of 1. Conditions were developed for a regioselective double alkylation at the C4 center of the A ring, which produced compound 32 as a single stereoisomer. Construction of the C ring of 1 was accomplished via a Diels-Alder reaction between sulfur-containing diene 43 and methacrolein (36), which after desulfurization and further functionalization yielded synthetic acanthoic acid. The described synthesis confirms the proposed stereochemistry of the natural product and represents a fully stereocontrolled entry into an underexplored class of biologically active diterpenes.

Stereoselective Synthesis of (−)-Acanthoic Acid

[reaction: see text] The first stereoselective synthesis of (-)-acanthoic acid (1) has been designed and accomplished. Our synthetic plan departs from (-) Wieland-Miesher ketone (7) and calls upon a Diels-Alder cycloaddition reaction for the construction of the C ring of 1. The described synthesis confirms the proposed stereochemistry of 1 and represents an efficient entry into an unexplored class of biologically active diterpenes.

Effects of acanthoic acid on TNF-alpha gene expression and haptoglobin synthesis.

Tumour necrosis factor-alpha (TNF-alpha) is a major pro-inflammatory cytokine inducing the synthesis and release of many inflammatory mediators. It is involved in immune regulation, autoimmune diseases, and inflammation. Our previous study demonstrated that acanthoic acid, (-)-pimara-9(11), 15-dien-19-oic acid, a pimaradiene diterpene isolated from Acanthopanax koreanum, inhibited TNF-alpha production. To extend our understanding of inhibitory effects of acanthoic acid on TNF-alpha production, its effects on TNF-alpha gene expression was tested. Based on the results from RT-PCR and promoter analysis of TNF-alpha, it was found that acanthoic acid suppressed TNF-alpha gene expression. But the same concentration of acanthoic acid had no effect on IL-6 gene expression. Haptoglobin is an acute phase protein which is induced by TNF-alpha. When liver cells were treated with acanthoic acid, haptoglobin synthesis was blocked by acanthoic acid. These data confirmed that acanthoic acid inhibited gene expression and biological function of TNF-alpha.

Suppression of Interleukin-1 and Tumor Necrosis Factor-α Production by Acanthoic Acid, (−)-Pimara-9(11),15-dien-19-oic Acid, and Its Antifibrotic Effectsin Vivo

Interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) are major proinflammatory cytokines inducing the synthesis and release of many inflammatory mediators. They are involved in immune regulation, autoimmune diseases, and inflammation. Acanthoic acid, (−)-pimara-9(11),15-dien-19-oic acid, is a pimaradiene diterpene isolated from the Korean medicinal plant,Acanthopanax koreanum.When human monocytes/macrophages stimulated with silica were treated with 0.1–10 μg/ml acanthoic acid, the production of IL-1 and TNF-α was inhibited up to 90%, but the production of interleukin-6 (IL-6) was not inhibited at all. At these concentrations, it had no cytotoxic effect on human monocytes/macrophages. It also suppressed the production of TNF-α by alveolar macrophages and lymphocytes stimulated with silica. In addition, acanthoic acid inhibited the release of superoxide anion and hydrogen peroxide from human monocytes/macrophages and neutrophils. To know the antifibrotic effects of acanthoic acid, its effects on fibroblast proliferation and collagen synthesis were tested. The proliferation of NIH3T3 cells was inhibited almost completely by the addition of the culture supernatants of human monocytes/macrophages treated with acanthoic acid, but not by the addition of acanthoic acid only.In vitroandin vivotreatment with acanthoic acid reduced collagen production by rat lung fibroblasts and lung tissue. Furthermore, acanthoic acid suppressed granuloma formation and fibrosis in the experimental silicosis. Acanthoic acid reduced serum GOT and GPT in the rats with cirrhosis induced by CCl4, and it was effective in reducing hepatic fibrosis and nodular formation. Taken together, these data indicate that acanthoic acid has a potent anti-inflammatory and antifibrosis effect by reducing IL-1 and TNF-α production.