Anti-Inflammatory Potential of Hexane Extract of Mud Lobster (Thalassina anomala) in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

Mud lobsters are crustaceans from the genus Thalassina which are lesser known and seldom seen but are nevertheless an important organism to the mangrove ecosystem. In Malaysia and Thailand, mud lobsters are eaten by locals as treatment for asthma. It is traditionally believed that they are effective in reducing the number of asthma attacks and severity of asthma symptoms. However, the therapeutic potential of mud lobster extract remains unclear and has not been fully elucidated or reported in any scientific study. The objectives of this study are to investigate the anti-inflammatory potential of mud lobster, Thalassina anomala extracts (hexane, chloroform and methanol) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, and to identify the potential bioactive compounds involved. An MTT assay was performed to determine the cytotoxicity of the T. anomala extracts on RAW 264.7 macrophages. Nitrite quantification assay and enzyme-linked immunosorbent assay (ELISA) were conducted to investigate the ability of the T. anomala extracts to suppress the secretion and expression of nitric oxide (NO), Prostaglandin E₂ (PGE₂) and proinflammatory cytokines (TNF-α, IL-6 and IL-1β) in LPS-stimulated macrophages. GC-MS analysis was done to identify putative metabolites. The hexane extract of T. anomala showed anti-inflammatory activity by significantly inhibiting the LPS-induced production of NO, PGE₂, interleukin- (IL-) 6, IL-1β and tumour necrosis factor-alpha (TNF-α) in a concentration-dependent manner. Hexane extract treatment with 100 μg/mL has decreased the NO secretion into 37 μM. Meanwhile, hexane extract at concentration of 100 μg/mL able to significantly suppressed PGE₂,TNF-α, IL-6 and IL-1β production into 2015 pg/mL, 2406 pg/mL, 460 pg/mL and 9.6 pg/mL, respectively. GC-MS analysis of the hexane extract revealed the presence of 19 putative compounds. The identified compounds were reported to have anti-inflammatory, antioxidant and antibacterial activities. These results suggest that the hexane extract of T. anomala potentially has anti-inflammatory properties and concentration dependently suppressed NO, PGE₂ and proinflammatory cytokines’ production in LPS-stimulated macrophages. The findings provide a rational basis of the traditional use of mud lobster for inflammation-associated ailments.

Effects of β-Glucan on the Release of Nitric Oxide by Macrophages Stimulated with Lipopolysaccharide

This research analyzed the effect of β-glucan that is expected to alleviate the production of the inflammatory mediator in macrophagocytes, which are processed by the lipopolysaccharide (LPS) of Escherichia. The incubated layer was used for a nitric oxide (NO) analysis. The DNA-binding activation of the small unit of nuclear factor-κB was measured using the enzyme-linked immunosorbent assay-based kit. In the RAW264.7 cells that were vitalized by Escherichia coli (E. coli) LPS, the β-glucan inhibited both the combatant and rendering phases of the inducible NO synthase (iNOS)-derived NO. β-Glucan increased the expression of the heme oxygenase-1 (HO-1) in the cells that were stimulated by E. coli LPS, and the HO-1 activation was inhibited by the tin protoporphyrin IX (SnPP). This shows that the NO production induced by LPS is related to the inhibition effect of β-glucan. The phosphorylation of c-Jun N-terminal kinases (JNK) and the p38 induced by the LPS were not influenced by the β-glucan, and the inhibitory κB-α (IκB-α) decomposition was not influenced either. Instead, β-glucan remarkably inhibited the phosphorylation of the signal transducer and activator of transcription-1 (STAT1) that was induced by the E. coli LPS. Overall, the β-glucan inhibited the production of NO in macrophagocytes that was vitalized by the E .coli LPS through the HO-1 induction and the STAT1 pathways inhibition in this research. As the host immune response control by β-glucan weakens the progress of the inflammatory disease, β-glucan can be used as an effective immunomodulator.

Inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cells by the norsesterterpene peroxide, epimuqubilin A

Seven norsesterterpene peroxides: epimuqubilin A (1), muqubilone B (2), unnamed cyclic peroxide ester (3), epimuqubilin B (4), sigmosceptrellin A methyl ester (5), sigmosceptrellin A (6), and sigmosceptrellin B methyl ester (7), isolated from the marine sponge Latrunculia sp., were examined with regard to their effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cells. The results indicated epimuqubilin A (1) possessed potent NO inhibitory activity against lipopolysaccharide (LPS)-induced nitric oxide release with an IC(50) value of 7.4 microM, a level three times greater than the positive control, L-N(G)-monomethyl arginine citrate, followed by 6 (sigmosceptrellin A, IC(50) = 9.9 microM), whereas other compounds exhibited only modest activity (Table 1). These compounds did not show appreciable cytotoxicity at their IC(50) values for NO-inhibitory activity. The structure-activity upon NO inhibition could be summarized as follows: (1) a monocyclic carbon skeleton framework was essential for activity, (2) free acids gave higher activity, (3) the orientation of H3-22 with an equatorial position increased activity, and (4) a bicyclic structure reduced activity. This is the first report of a norsesterterpene peroxide with NO-inhibitory activity. In addition, compounds 1-7 were also evaluated for their inhibitory activities in the yeast glycogen synthase kinase-3beta assay. In summary, several norsesterterpene peroxides showed novel biological activities of inhibition in NO production, suggesting that these might provide leads for anti-inflammatory or cancer chemopreventive agents.