ABSTRACT
Hypericumperforatum (H. perforatum) ethanol extract has been found to inhibit lipopolysaccharide-induced production of inflammatory mediators and cytokines in cultured macrophages. Therefore, it may be able to protect the host from excessive inflammation during viral infection. In the current study, the immune-regulatory effect of H. perforatum extract was evaluated in A549 lung epithelial cells and BALB/c mice exposed to Influenza A/PR/8/34 H1N1 virus. In A549 cells, the extract (30 µg/mL) significantly inhibited influenza virus induced monocyte chemotactic protein (MCP)-1 and interferon-γ induced protein 10 kD (IP-10), but dramatically increased interleukin-6 (IL-6). In mice inoculated intranasally with 10(7.9) EID50 of Influenza A/PR/8/34 H1N1 (high dose), daily oral treatment of H. perforatum extract at a rate of 110 mg/kg of body weight increased lung viral titer, bronchoalveolar lavage (BAL) pro-inflammatory cytokine and chemokine levels, and the infiltration of pro-inflammatory cells in the lung 5 days post-inoculation, as compared to ethanol vehicle treated mice. Transcription of suppressor of cytokine signaling 3 (SOCS3) was increased by H. perforatum extract both in A549 cells and BALB/c mice, which could have interrupted anti-viral immune response and thus led to the inefficient viral clearance and increased lung inflammation. H. perforatum treatment resulted in minor reduction in viral titer without affecting body weight when mice were inoculated with a lower dose (~10(5.0) EID50) and H. perforatum was applied in the later phase of infection. Mice challenged intranasally with high dose of influenza virus (10(7.9) EID50) suffered from a higher mortality rate when dosed with H. perforatum extract. In conclusion, the current study showed that SOCS3 elevation by H. perforatum may cause impaired immune defense against influenza virus infection and lead to higher mortality.
Subject(s)
Gene Expression Regulation/drug effects , Hypericum/chemistry , Influenza A Virus, H1N1 Subtype , Orthomyxoviridae Infections/drug therapy , Orthomyxoviridae Infections/immunology , Plant Extracts/pharmacology , Administration, Oral , Analysis of Variance , Animals , Blotting, Western , Bronchoalveolar Lavage Fluid/chemistry , Cell Line , Chemokine CXCL10/antagonists & inhibitors , Chemokines/analysis , Cytokines/analysis , DNA Primers/genetics , Enzyme-Linked Immunosorbent Assay , Humans , Interleukin-6/metabolism , Mice , Mice, Inbred BALB C , Monocyte Chemoattractant Proteins/antagonists & inhibitors , Plant Extracts/administration & dosage , Suppressor of Cytokine Signaling 3 Protein , Suppressor of Cytokine Signaling Proteins/genetics , Suppressor of Cytokine Signaling Proteins/metabolismABSTRACT
Bauer alkylamide 11 and Bauer ketone 23 were previously found to be partially responsible for Echinacea angustifolia anti-inflammatory properties. This study further tested their importance using the inhibition of prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production by RAW264.7 mouse macrophages in the absence and presence of lipopolysaccharide (LPS) and E. angustifolia extracts, phytochemical enriched fractions, or pure synthesized standards. Molecular targets were probed using microarray, qRT-PCR, Western blot, and enzyme assays. Fractions with these phytochemicals were more potent inhibitors of LPS-induced PGE(2) production than E. angustifolia extracts. Microarray did not detect changes in transcripts with phytochemical treatments; however, qRT-PCR showed a decrease in TNF-alpha and an increase of iNOS transcripts. LPS-induced COX-2 protein was increased by an E. angustifolia fraction containing Bauer ketone 23 and by pure phytochemical. COX-2 activity was decreased with all treatments. The phytochemical inhibition of PGE(2) production by Echinacea may be due to the direct targeting of COX-2 enzyme.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Cyclooxygenase 2 Inhibitors/pharmacology , Cyclooxygenase 2/immunology , Echinacea/chemistry , Ketones/pharmacology , Plant Extracts/pharmacology , Polyunsaturated Alkamides/pharmacology , Animals , Cell Line , Dinoprostone/antagonists & inhibitors , Dinoprostone/immunology , Macrophages/drug effects , Macrophages/enzymology , Macrophages/immunology , Mice , Nitric Oxide/antagonists & inhibitors , Nitric Oxide/immunology , Nitric Oxide Synthase Type II/genetics , Nitric Oxide Synthase Type II/immunologyABSTRACT
Dihydroindolo[2,1-a]isoquinolines were synthesized from tetrahydroisoquinolines and alpha-fluoroaldehydes by a novel two-step procedure. These compounds exhibited significant immunosuppressive activity against IL-2, IL-10 and IFN-gamma.
