Cuong Trinh Tat

Background: Clerodendrum chinense has been reported to possess several important biological activities. However, the anti-inflammation and insulin-related properties of isolated compounds from this plant have not yet been investigated. Objectives: This study focuses on extracting compounds and evaluating improvements in insulin resistance through the anti-inflammatory potential and inhibition of reactive oxygen species (ROS) of hispidulin from Vietnamese C. chinense leaves. Methods: Ethanol was used to separate the compounds from the leaves of Vietnamese C. chinense. 1D, 2D-NMR, and ESI-MS spectra were used to analyze the structural identity of the isolated compounds. Compound 1 (hispidulin) was evaluated for anti-inflammation and ROS in Raw 264.7 cells: Anti-inflammatory cytokine inhibition ability was analyzed by the ELISA method; Western blotting was used for the expression levels of phosphorylated ERK1/2, p38, p47phox, and GLUT4. ROS was assessed by immunofluorescence; a luminometer device was used to measure NADPH oxidase activity. The ability to absorb glucose and counteract insulin resistance was evaluated in 3T3-L1 cells via insulin-induced glucose uptake using immunofluorescence dye. Results: One compound isolated from the leaves of Vietnamese C. chinense was identified as hispidulin. Hispidulin at a concentration of 50 μg/mL significantly inhibited tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 in LPS-induced macrophages (P < 0.001). Moreover, in LPS-stimulated macrophages, the phosphorylation of p38 and ERK1/2, NADPH oxidase activity, as well as the phosphorylation of p47phox, were reduced at a concentration of 50 μg/mL of hispidulin (P < 0.001). More importantly, 3T3-L1 cells with inhibited insulin activity were able to regain glucose uptake and insulin responsiveness through GLUT4 expression when treated with 50 µg/mL of hispidulin (P < 0.001). Conclusions: The data confirmed the presence of hispidulin in the chemical composition of Vietnamese C. chinense leaves. The results indicated that hispidulin inhibited LPS- and ROS-mediated inflammation in macrophages. More importantly, the data have shown that hispidulin enhances glucose uptake and improves insulin activity in 3T3-L1 cells.

Background: Pinoresinol, an ingredient in Gnetum montanum Markgr, has been demonstrated to be an anti-inflammatory substance. However, the anti-inflammatory activity of pinoresinol requires further research. Objectives: This study elucidates the effects of pinoresinol from Vietnamese G. montanum Markgr in suppressing lipopolysaccharide (LPS)-stimulated inflammation and the production of reactive oxygen species (ROS) in macrophages. Methods: Methanol was used to extract pinoresinol from Vietnamese G. montanum Markgr. The purity of pinoresinol was evaluated by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 was analyzed by Western blot assay. Immunofluorescence was used to measure ROS generated from Raw 264.7 cells. Results: Lipopolysaccharide-mediated secretion of proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β was significantly decreased by pinoresinol (40 µg/mL, P < 0.001). Furthermore, LPS-induced phosphorylation of ERK1/2 and p38 was markedly suppressed by pinoresinol (40 µg/mL, P < 0.001). Importantly, ROS generated by LPS in macrophages was inhibited by pinoresinol at a concentration of 40 µg/mL (P < 0.001). Conclusions: These data further elucidate the anti-inflammatory pathways of pinoresinol, targeting the mitogen-activated protein kinase (MAPK) signaling pathways and ROS.

Hygrophila ringens var. ringens is a medicinal plant of the Acanthaceae family. A soluble polysaccharide is extracted from H. ringens seeds using warm water, followed by deproteinization and purification using column chromatography. DL1 is characterized comprehensively using spectroscopic and chromatographic techniques and identified as a polymer containing xylose (Xyl; 78.5%) and 4‐O‐methyl‐d‐glucuronic acid (4‐O‐MeGlcA; 21.5 %). The most prominent glycosidic linkages detected are terminal‐xylose (T‐Xyl); 1,2,3,4‐Xylp; 1,2,4‐Xylp; and T‐4‐O‐MeGlcA. DL1 belongs to the xylan group and is a 4‐O‐methylglucuronoxylan. DL1 exhibits inhibition of bovine serum albumin denaturation with IC₅₀ values of 0.35 mg mL⁻¹ and a similar activity to diclofenac (non‐steroidal anti‐inflammatory drug). In a model of lipopolysaccharide‐stimulated macrophages, DL1 (20–40 µg mL⁻¹) strongly inhibits inflammatory cytokines and reactive oxygen species release without having significant macrophage cytotoxicity. The inhibitory effect of DL1 on inflammatory cytokines is mediated by the activation of mitogen‐activated protein kinases by inhibiting the phosphorylation of p38 and extracellular signal‐regulated kinase. These results highlight the potential of DL1 for treating inflammation through its cytokine‐suppressive activity.

Pseuderanthemum carruthersii (Seem.) Guillaumin is a native tree in Vietnam. The water extract of the leaves from this tree gives a highly viscous product that has been used to heal wounds and treat inflammations. Our previous studies showed that the leaves of P. carruthersii have a high content of polysaccharides. In this study, the structure and influence of the neutral polysaccharide from Pseuderanthemum carruthersii (PCA1) on lipopolysaccharide (LPS)-stimulated RAW264.7 cells were investigated. The PCA1 isolated from P. carruthersii is a galactan-type polysaccharide, containing galactose (77.0%), 3-O-methyl galactose (20.0%), and arabinose (3.0%). Linkage analysis of PCA1 showed that both the 3-O-methyl galactose and galactose were 1,4-linked. The presence of 3-O-methyl galactose units as part of the polysaccharide is important and can be used as a chemotaxonomic marker. The molecular weight of the PCA1 was 170 kDa. A PCA1 concentration of 30–40 μg/mL strongly inhibited TNFα, IL-1β, and IL-6 inflammatory cytokine production, and reactive oxygen species (ROS) release. PCA1 had inhibitory activities on pro-inflammatory cytokine and ROS release in LPS-stimulated mouse macrophages in vitro through MAPK signaling.

Wedelolactone is known to have biological activities such as anti-inflammation hepatitis, anti-hepatotoxic activity, and trypsin inhibitory effect. However, up to date, there has not been any deep study on the role of wedelolactone for zymosan-induced signaling pathways in the process of regulating the excessive inflammatory responses in host. Here, we demonstrated that wedelolactone plays an essential role for regulation of zymosan-induced inflammatory responses in murine bone marrow-derived macrophages (BMDMs). The zymosan-mediated secretion of tumor necrosis factor-alpha (TNF)-alpha), interleukin (IL)-6), and IL12p40 but not IL-10 in BMDMs was significantly inhibited by pre-treatment with wedelolactone (30 mu g/mL, P < 0.001). Furthermore, zymosan-induced supreoxide generation, NADPH oxidase (P < 0.001), phosphorylation of p47phox in BMDMs were significantly reduced by pre-treatment of wedelolactone (30 mu g/mL). Collectively, these data indicated that wedelolactone reduced zymosan-induced inflammatory responses. Moreover, in-vivo wedelolactone (30 mg/kg) was significantly rescued from zymosan-induced shock through inhibition of systemic inflammatory cytokine levels.