Secoiridoid Glucosides and Anti-Inflammatory Constituents from the Stem Bark of Fraxinus chinensis.

Qin Pi (Fraxinus chinensis Roxb.) is commercially used in healthcare products for the improvement of intestinal function and gouty arthritis in many countries. Three new secoiridoid glucosides, (8E)-4''-O-methylligstroside (1), (8E)-4''-O-methyldemethylligstroside (2), and 3'',4''-di-O-methyl-demethyloleuropein (3), have been isolated from the stem bark of Fraxinus chinensis, together with 23 known compounds (4-26). The structures of the new compounds were established by spectroscopic analyses (1D, 2D NMR, IR, UV, and HRESIMS). Among the isolated compounds, (8E)-4''-O-methylligstroside (1), (8E)-4''-O-methyldemethylligstroside (2), 3'',4''-di-O-methyldemethyloleuropein (3), oleuropein (6), aesculetin (9), isoscopoletin (11), aesculetin dimethyl ester (12), fraxetin (14), tyrosol (21), 4-hydroxyphenethyl acetate (22), and (+)-pinoresinol (24) exhibited inhibition (IC50 ≤ 7.65 µg/mL) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leuckyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 1, 9, 11, 14, 21, and 22 inhibited fMLP/CB-induced elastase release with IC50 ≤ 3.23 µg/mL. In addition, compounds 2, 9, 11, 14, and 21 showed potent inhibition with IC50 values ≤ 27.11 µM, against lipopolysaccharide (LPS)-induced nitric oxide (NO) generation. The well-known proinflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6), were also inhibited by compounds 1, 9, and 14. Compounds 1, 9, and 14 displayed an anti-inflammatory effect against NO, TNF-α, and IL-6 through the inhibition of activation of MAPKs and IκBα in LPS-activated macrophages. In addition, compounds 1, 9, and 14 stimulated anti-inflammatory M2 phenotype by elevating the expression of arginase 1 and Krüppel-like factor 4 (KLF4). The above results suggested that compounds 1, 9, and 14 could be considered as potential compounds for further development of NO production-targeted anti-inflammatory agents.

Triptolide attenuates lipopolysaccharide-induced inflammatory responses in human endothelial cells: involvement of NF-κB pathway.

BACKGROUND: Endothelial cell inflammation is a central event in the pathogenesis of numerous cardiovascular diseases, including sepsis and atherosclerosis. Triptolide, a principal bioactive ingredient of Traditional Chinese Medicine Tripterygium wilfordii Hook.F., displays anti-inflammatory actions in vivo. However, the mechanisms underlying these beneficial effects remain undetermined. The present study investigated the effects and possible mechanisms of triptolide on lipopolysaccharide (LPS)-induced inflammatory responses in human umbilical vein endothelial cells (HUVECs). METHODS: The effects of triptolide on the LPS-induced production and expression of inflammatory molecules, monocyte adhesion and activation of nuclear factor (NF)-κB pathway were examined in cultured HUVECs. RESULTS: In cultured HUVECs, pre-treatment with triptolide dose-dependently attenuated LPS-induced cytokine and chemokine production, adhesion molecule expression and monocyte adhesion. Mechanistically, triptolide was found to dose-dependently inhibit the LPS-induced increases in the DNA binding activity of NF-κB p65 associated with attenuating IκBα phosphorylation and its degradation. Additionally, the present study revealed that triptolide inhibited LPS-triggered NF-κB transcriptional activation in a dose-dependent manner. CONCLUSIONS: The results of the present study indicated that triptolide suppresses the inflammatory response of endothelial cells possibly via inhibition of NF-κB activation.

Directed self-assembly of herbal small molecules into sustained release hydrogels for treating neural inflammation.

Self-assembling natural drug hydrogels formed without structural modification and able to act as carriers are of interest for biomedical applications. A lack of knowledge about natural drug gels limits there current application. Here, we report on rhein, a herbal natural product, which is directly self-assembled into hydrogels through noncovalent interactions. This hydrogel shows excellent stability, sustained release and reversible stimuli-responses. The hydrogel consists of a three-dimensional nanofiber network that prevents premature degradation. Moreover, it easily enters cells and binds to toll-like receptor 4. This enables rhein hydrogels to significantly dephosphorylate IκBα, inhibiting the nuclear translocation of p65 at the NFκB signalling pathway in lipopolysaccharide-induced BV2 microglia. Subsequently, rhein hydrogels alleviate neuroinflammation with a long-lasting effect and little cytotoxicity compared to the equivalent free-drug in vitro. This study highlights a direct self-assembly hydrogel from natural small molecule as a promising neuroinflammatory therapy.

Structural characterization and immunomodulatory activity of a novel polysaccharide from Ficus carica.

A novel polysaccharide (FCPW80-2) with a molecular weight of 1.21 × 105 Da was first isolated from Ficus carica through hot water extraction and several chromatographic methods. The structure of FCPW80-2 was determined by chemical and instrumental analysis. The results showed that the backbone of FCPW80-2 consists of (1→5)-linked α-l-Ara, (1→3,6)-linked ß-d-Man and (1→4,6)-linked ß-d-Gal. The branches of FCPW80-2 consist of (1→4)-linked α-d-Glc and (1→3)-linked ß-l-Rha terminated with (1→)-linked ß-d-Glc. In vitro immunomodulatory activity assays revealed that FCPW80-2 could markedly promote the secretion of cytotoxic molecules (NO) and cytokines (TNF-α and IL-6) as well as the phagocytosis of RAW264.7 macrophages. Moreover, TLR2 was found to be a pattern recognition receptor (PRR) of FCPW80-2, and its related mitogen-activated protein kinases (MAPKs), including p-ERK, p-JNK and p-p38, were rapidly upregulated by FCPW80-2 in RAW264.7 macrophages. Furthermore, FCPW80-2 could not only upregulate the expression of p-p65 and p-IκB-α, but also cause the translocation of nuclear factor-kappa B (NF-κB) p65 from cytosol to nuclei in RAW264.7 macrophages. The results demonstrated that MAPK and NF-κB signalling pathways participated in FCPW80-2-induced macrophage activation and FCPW80-2 could be developed as a potential immunomodulating functional food.

Total tanshinones exhibits anti-inflammatory effects through blocking TLR4 dimerization via the MyD88 pathway.

Tanshinones belong to a group of lipophilic constituents of Salvia miltiorrhiza Bunge (Danshen), which is widely used in traditional Chinese medicine. A deluge of studies demonstrated that tanshinones exert anti-inflammatory effects, but the underlying mechanisms remain unclear to date. This study investigated the anti-inflammatory effects and mechanisms of total tanshinones (TTN). TTN suppressed the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) and the secretion of TNF-α, IL-6, and IL-1ß in RAW264.7 cells, bone marrow-derived macrophages, and THP-1 cells. TTN attenuated the LPS-induced transcriptional activity of NF-κB and decreased IκB-α and IKK phosphorylation and NF-κB/p65 nuclear translocation. Furthermore, TTN inhibited the LPS-induced transcriptional activity of AP-1, which was induced by the reduction of JNK1/2, ERK1/2, and p38MAPK phosphorylation. TTN blocked LPS-induced Toll-like receptor 4 (TLR4) dimerization, which consequently decreased MyD88 recruitment and TAK1 phosphorylation. In addition, TTN pretreatment effectively inhibited xylene-induced ear edema and LPS-induced septic death and improved LPS-induced acute kidney injury in mice. TTN exerts anti-inflammatory effects in vitro and in vivo by blocking TLR4 dimerization to activate MyD88-TAK1-NF-κB/MAPK signaling cascades, which provide the molecular basis of the anti-inflammatory effect of Danshen and suggest that TTN is a potential agent for the treatment of inflammatory diseases.