In vivo effect of quantified flavonoids-enriched extract of Scutellaria baicalensis root on acute lung injury induced by influenza A virus.

Scutellaria baicalensis root is traditionally used for the treatment of common cold, fever and influenza. Flavonoids are the major chemical components of S. baicalensis root. To evaluate the therapeutic effects and action mechanism of flavonoids-enriched extract from S. baicalensis root (FESR) on acute lung injury (ALI) induced by influenza A virus (IAV) in mice. The anti-influenza, anti-inflammatory and anti-complementary properties of FESR and the main flavonoids were evaluated in vitro. Mice were challenged intranasally with influenza virus H1N1 (A/FM/1/47) 2  h before treatment. FESR (50, 100 and 200  mg/kg) was administrated intragastrically. Baicalin (BG), the most abundant compound in FESR was given as reference control. Survival rates, life spans and lung indexes of IAV-infected mice were measured. Histopathological changes, virus levels, inflammatory markers and complement deposition in lungs were analyzed. Compared with the main compound BG, FESR and lower content aglycones (baicalein, oroxylin A, wogonin and chrysin) in FESR significantly inhibited H1N1 activity in virus-infected Madin-Darby canine kidney (MDCK) cells and markedly decreased nitric oxide (NO) production from lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In vitro assays showed that FESR and BG had no anti-complementary activity whereas baicalein, oroxylin A, wogonin and chrysin exhibited obvious anti-complementary activity. Oral administration of FESR effectively protected the IAV-infected mice, increased the survival rate (FESR: 67%; BG: 33%), decreased the lung index (FESR: 0.90; BG: 1.00) and improved the lung morphology in comparing with BG group. FESR efficiently decreased lung virus titers, reduced haemagglutinin (HA) titers and inhibited neuraminidase (NA) activities in lungs of IAV-infected mice. FESR modulated the inflammatory responses by decreasing the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1), and increasing the levels of interferon-γ (IFN-γ) and interleukin-10 (IL-10) in lung tissues. Although showing no anti-complementary activity in vitro, FESR obviously reduced complement deposition and decreased complement activation product level in the lung . FESR has a great potential for the treatment of ALI induced by IAV and the underlying action mechanism might be closely associated with antiviral, anti-inflammatory and anti-complementary properties. Furthermore, FESR resulted in more potent therapeutic effect than BG in the treatment of IAV-induced ALI.

Zhi HJ ，Zhu HY ，Zhang YY ，Lu Y ，Li H ，Chen DF ... -  《-》

Exploring the effective materials of flavonoids-enriched extract from Scutellaria baicalensis roots based on the metabolic activation in influenza A virus induced acute lung injury.

Flavonoids-enriched extract from Scutellaria baicalensis roots (FESR) ameliorated influenza A virus (IAV) induced acute lung injury (ALI) in mice by inhibiting the excessive activation of complement system in vivo. However, FESR had no anti-complementary activity in vitro. In order to reveal the effective materials of FESR for the treatment of IAV-induced ALI, the present research explored the metabolic process of FESR both in nomal and IAV infected mice by the method of UHPLC-ESI-LTQ/MS, as well as the metabolic activating mechanism. The results showed that the inactive flavonoid glycosides of FESR were partly metabolized into anti-complementary aglycones in vivo, mainly including 5,7,4'-trihydroxy-8-methoxy-flavone, norwogonin, baicalein, wogonin, oroxylin A and chrysin. Moreover, compared with the normal mice, IAV-induced ALI mice exhibited more efficient on producing and absorbing these active metabolites, with AUC0-t and Cmax in plasma and concentrations in lungs and intestines markedly elevated in the IAV treated groups (P <  0.05). Interestingly, the intestinal bacteria from IAV-induced ALI mice showed stronger β-glucuronidase activity and also had higher efficiency on transforming FESR to the flavonoid aglycones. These findings suggested that the anti-complementary aglycones produced by metabolic activation in vivo should be the potential effective materials of FESR against IAV infections, and intestinal bacteria might play an important role on the higher bioavailability of FESR in IAV infected mice. Additionally, the animals under the pathological state are more suitable for the metabolic study of traditional Chinese medicine.

Zhi H ，Jin X ，Zhu H ，Li H ，Zhang Y ，Lu Y ，Chen D ... -  《-》

Flavonoids from Houttuynia cordata attenuate H1N1-induced acute lung injury in mice via inhibition of influenza virus and Toll-like receptor signalling.

Influenza virus is one of the most important human pathogens, causing substantial seasonal and pandemic morbidity and mortality. Houttuynia cordata is a traditionally used medicinal plant for the treatment of pneumonia. Flavonoids are one of the major bioactive constituents of Houttuynia cordata. This study was designed to investigate the therapeutic effect and mechanism of flavonoid glycosides from H. cordata on influenza A virus (IAV)-induced acute lung injury (ALI) in mice. Flavonoids from H. cordata (HCF) were extracted from H. cordata and identified by high-performance liquid chromatography. Mice were infected intranasally with influenza virus H1N1 (A/FM/1/47). HCF (50, 100, or 200 mg/kg) or Ribavirin (100 mg/kg, the positive control) were administered intragastrically. Survival rates, life spans, weight losses, lung indexes, histological changes, inflammatory infiltration, and inflammatory markers in the lungs were measured. Lung virus titers and neuraminidase (NA) activities were detected. The expression of Toll-like receptors (TLRs) and levels of NF-κB p65 phosphorylation (NF-κB p65(p)) in the lungs were analysed. The effects of HCF on viral replication and TLR signalling were further evaluated in cells. HCF contained 78.5% flavonoid glycosides. The contents of rutin, hyperin, isoquercitrin, and quercitrin in HCF were 8.8%, 26.7%, 9.9% and 31.7%. HCF (50, 100 and 200 mg/kg) increased the survival rate and life span of mice infected with the lethal H1N1 virus. In H1N1-induced ALI, mice treated with HCF (50, 100 and 200 mg/kg) showed lesser weight loss and lower lung index than the model group. The lungs of HCF-treated ALI mice presented more intact lung microstructural morphology, milder inflammatory infiltration, and lower levels of monocyte chemotactic protein 1 (MCP-1), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α) and malondialdehyde (MDA) than in the model group. Further investigation revealed that HCF exerted antiviral and TLR-inhibitory effects in vivo and in vitro. HCF (50, 100 and 200 mg/kg) reduced lung H1N1 virus titers and inhibited viral NA activity in mice. HCF (100 and 200 mg/kg) elevated the levels of interferon-β in lungs. HCF also decreased the expression of TLR3/4/7 and level of NF-κB p65(p) in lung tissues. In vitro experiments showed that HCF (50, 100 and 200 μg/ml) significantly inhibited viral proliferation and suppressed NA activity. In RAW 264.7 cells, TLR3, TLR4, and TLR7 agonist-stimulated cytokine secretion, NF-κB p65 phosphorylation, and nuclear translocation were constrained by HCF treatment. Furthermore, among the four major flavonoid glycosides in HCF, hyperin and quercitrin inhibited both viral replication and TLR signalling in cells. HCF significantly alleviated H1N1-induced ALI in mice, which were associated with its dual antiviral and anti-inflammatory effects via inhibiting influenzal NA activity and TLR signalling. among the four major flavonoid glycosides in HCF, hyperin and quercitrin played key roles in the therapeutic effect of HCF.

Ling LJ ，Lu Y ，Zhang YY ，Zhu HY ，Tu P ，Li H ，Chen DF ... -  《-》

Anti-H1N1 virus, cytotoxic and Nrf2 activation activities of chemical constituents from Scutellaria baicalensis.

Ji S ，Li R ，Wang Q ，Miao WJ ，Li ZW ，Si LL ，Qiao X ，Yu SW ，Zhou DM ，Ye M ... -  《-》

Antiviral activity of baicalin against influenza A (H1N1/H3N2) virus in cell culture and in mice and its inhibition of neuraminidase.

Ding Y ，Dou J ，Teng Z ，Yu J ，Wang T ，Lu N ，Wang H ，Zhou C ... -  《-》