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Journal of Ethnopharmacology 130 (2010) 392–397

Contents lists available at ScienceDirect

Journal of Ethnopharmacology

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thnopharmacological communication

araxacum officinale protects against lipopolysaccharide-induced acute lungnjury in mice

iben Liu1, Huanzhang Xiong1, Jiaqi Ping, Yulin Ju, Xuemei Zhang ∗

epartment of Animal Medicine, Agricultural College of Yanbian University, Longmen Street, Longjing, Jilin 133400, PR China

r t i c l e i n f o

rticle history:eceived 9 February 2010eceived in revised form 12 May 2010ccepted 17 May 2010vailable online 25 May 2010

eywords:araxacum officinalenflammationronchoalveolar lavage fluid (BALF)

a b s t r a c t

Aim of the study: Taraxacum officinale has been frequently used as a remedy for inflammatory diseases.In the present study, we investigated the in vivo protective effect of Taraxacum officinale on acute lunginjury (ALI) induced by lipopolysaccharide (LPS) in mice.Materials and methods: Taraxacum officinale at 2.5, 5 and 10 mg/kg was orally administered once per day for5 days consecutively, followed by 500 �g/kg LPS was instilled intranasally. The lung wet/dry weight (W/D)ratio, protein concentration and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF)were determined. Superoxidase dismutase (SOD) and myeloperoxidase (MPO) activities, and histologicalchange in the lungs were examined. The levels of inflammatory cytokine tumor necrosis factor-� (TNF-�)and interleukin-6 (IL-6) in the BALF were measured using ELISA.

ytokineuperoxidase dismutase (SOD)yeloperoxidase (MPO)

Results: We found that Taraxacum officinale decreased the lung W/D ratio, protein concentration andthe number of neutrophils in the BALF at 24 h after LPS challenge. Taraxacum officinale decreased LPS-induced MPO activity and increased SOD activity in the lungs. In addition, histopathological examinationindicated that Taraxacum officinale attenuated tissue injury of the lungs in LPS-induced ALI. Furthermore,Taraxacum officinale also inhibited the production of inflammatory cytokines TNF-� and IL-6 in the BALFat 6 h after LPS challenge in a dose-dependent manner.

sugg

Conclusions: These results

. Introduction

Acute lung injury (ALI) is defined as a syndrome of acute andersistent lung inflammation with increased vascular permeabil-

ty. The main characteristics of ALI are extensive neutrophil influxnto the lungs, the production of pro-inflammatory mediators fromnflammatory cells, and damage to lung epithelial and endothelialurfaces leading to protein-rich edema and impairment of respi-atory function (Jeyaseelan et al., 2005; Piantadosi and Schwartz,004). Acute respiratory distress syndrome (ARDS) is the mostevere form of ALI, and it remains refractory to therapy. ALI andRDS are associated with the development of multiple organ dys-

unction syndrome (MODS), which plays a pivotal role in the deathf patients with multiple transfusions, shock, sepsis, and ischemia-eperfusion (Bhatia and Moochhala, 2004; Lee and Downey, 2001).

lthough recent evidence-based advances in clinical managementnd extensive investigations into new strategies for treatment,ave shown promise, the mortality from ALI/ARDS remains high inhe last decade (MacCallum and Evans, 2005; Jain and DalNogare,

∗ Corresponding author. Tel.: +86 433 3264682; fax: +86 433 3263483.E-mail address: zhangmeixue2000@yahoo.com.cn (X. Zhang).

1 These authors contributed equally to this work.

378-8741/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved.oi:10.1016/j.jep.2010.05.029

est that Taraxacum officinale protects against LPS-induced ALI in mice.© 2010 Elsevier Ireland Ltd. All rights reserved.

2006). The development of efficient therapeutic approaches thatcould improve or complement for current strategies is urgentlyneeded.

Taraxacum officinale has long been used in traditional orientalmedicine for its lactating, choleretic, diuretic, antirheumatic andanti-inflammatory properties (Kisiel and Barszcz, 2000; Ahmad etal., 2000). Earlier pharmacological studies on this plant revealedthat the crude extract showed an in vitro bactericidal effect againstStaphylococcus aureus and inhibitory action against Mycobacteriumtuberculosis and Leptospira. It is also a relatively safe herb with anLD50 of 59 g/kg in mice and has a record of relatively few sideeffects (Bensky and Gamble, 1986). Pharmacological activities ofTaraxacum officinale including its anti-inflammatory activity havebeen in part evaluated so far (Schütz et al., 2006; Jeon et al., 2008).Moreover, the aqueous extract of Taraxacum officinale was assessedto contain acute anti-inflammatory activity by showing its pro-tective effects against cholecystokinin-induced acute pancreatitisin rats (Seo et al., 2005). Taraxacum officinale is widely used fortreating various inflammatory or infectious diseases clinically such

as hepatitis, upper respiratory tract infections, bronchitis, pneu-monia, and as a compress for its anti-mastopathy activity (Leu etal., 2005; Sweeney et al., 2005). Although Taraxacum officinale isused for treating diseases related with inflammation in the folkof China, its use has mainly been based on empirical findings.

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hether Taraxacum officinale has protective effect on ALI, and whathe underlying mechanisms of Taraxacum officinale action are haveever been investigated. In the present study, we studied the effectsf Taraxacum officinale on an experimental model of acute lungnflammation induced by LPS in vivo and tried to clarify the mech-nism involved. Our results might provide a pharmacological basisn its folkloric use for the treatment of inflammatory diseases.

. Materials and methods

.1. Animals

Male BALB/c mice, 8–12 weeks old, were purchased from theenter of Experimental Animals of Yanbian Medical College ofanbian University (Yanji, Jilin, China). The mice were kept inicroisolator cages and received food and water ad libitum. Labora-

ory temperature was 24 ± 1 ◦C, and relative humidity was 40–80%.efore experimentation, the mice were allowed to adapt to thexperimental environment for a minimum of 1 week. All experi-ents were performed in accordance with the National Institutes

f Health (NIH) guide for the Care and Use of Laboratory Animals.he experimental procedures were approved by the Ethical Com-ittee for the Experimental Use of Animals at Yanbian University

Yanji, Jilin, China).

.2. Reagents

LPS (Escherichia coli 055:B5) was purchased from Sigma Chem-cal Co. (St. Louis, MO, USA). Dexamethasone (DEX) Sodiumhosphate Injection (no. H41020055) was purchased from Changleharmaceutical Co. (Xinxiang, Henan, China). Mouse TNF-� and IL-ELISA kits were purchased from Biolegend, Inc. (San Diego, CA,SA). Bicinchoninic acid (BCA) protein assay kit, myeloperoxidase

MPO) and superoxide dismutase (SOD) determination kits wereurchased from Nanjing Jiancheng Bioengineering Institute (Nan-

ing, Jiangsu, China).

.3. Preparation of aqueous extract of Taraxacum officinale

Taraxacum officinale was extracted three times by decocting theried prescription of herbs with boiling distilled water for 5 h (3,, and 1 h); after filtration, the filtrate was concentrated under aeduced pressure. This plant was collected from Changbai Moun-ain area of Jilin Province (Jilin, China) in July 2008. This plant wasdentified macroscopically and microscopically according to theharmacopoeia of China, and the voucher specimen (no. 080721)as deposited at the Herbarium of Yanbian University (Yanji, Jilin,hina).

.4. Establishment of the ALI model and treatment regimen

The mice were divided randomly into six groups: control group,PS group, Taraxacum officinale (at doses of 2.5, 5 and 10 mg/kg,espectively) + LPS groups, and DXM + LPS group. Taraxacum offici-ale at 2.5, 5 and 10 mg/kg was administered orally once per dayor 5 days consecutively, while DXM at 2 mg/kg was given with anntraperitoneal injection once 1 h prior to LPS administration as aositive control. The doses of these drugs we chose were on theasis of previous studies and our preliminary experiments. Micerom the control and LPS groups received the equal volume dis-

illed water instead of Taraxacum officinale or DXM. One hour afteraraxacum officinale treatment on day 5, mice were slightly anes-hetized with an inhalation of diethyl ether; then, 500 �g/kg LPSas instilled intranasally (i.n.) in 50 �l PBS to induce lung injury

Szarka et al., 1997). Control mice were given a 50 �l PBS i.n. instil-

acology 130 (2010) 392–397 393

lation without LPS. Animals recovered quickly from the procedurewith only mild discomfort.

2.5. Collection of bronchoalveolar lavage fluid (BALF) and cellcounting

BALF was collected as previously described (Hashimoto et al.,2004). At 6 h (for cytokines) or 24 h (for protein and cell count-ing) after LPS challenge, mice were sacrificed by exsanguination.BALF was obtained by intratracheal instillation, and the lungs werelavaged three times with 0.8 ml of sterile PBS. The BALF fromeach sample was centrifuged (4 ◦C, 420 × g, 15 min), and super-natants were stored at −80 ◦C for subsequent analysis of proteinand cytokine levels. Cell pellets were re-suspended in PBS for totalcell counts using a hemacytometer, and cytospins were preparedfor differential cell counts by staining with a modified Giemsamethod. At least 200 cells were counted per slide.

2.6. Lung wet/dry weight (W/D) ratio

At 24 h after LPS challenge, mice were euthanized, the right lungwas excised, blotted dry and weighed, and then placed in an ovenat 80 ◦C for 48 h to obtain the “dry” weight. The ratio of the wet lungto the dry lung was calculated to assess tissue edema. The left lungwas used for the histopathological examination.

2.7. Protein analysis

Protein concentration in the supernatants of the BALF wasquantified using the BCA protein assay kit to evaluate vascularpermeability to airways. Briefly, the samples were placed in a flat-bottom 96-well ELISA plate, BCA solution was added and incubatedat 37 ◦C for 30 min. Absorbance was measured at 562 nm on amicroplate reader (TECAN-GENious, Austria). A standard curve wasestablished using a serial dilution of protein standard. Protein wasexpressed as milligram per milliliter of BALF.

2.8. Assays for SOD and MPO activities

SOD and MPO activities were measured as previously described(Shen et al., 2009). At 24 h after LPS challenge, whole lung washomogenized using a homogenizer. The homogenate was then cen-trifuged at 3000 rpm for 10 min at 4 ◦C. The supernatants obtainedwere used for assay of SOD activity. SOD activity was evaluatedaccording to the xanthine oxidase method and using commerciallyavailable reagents, according to the manufacturer’s instructions.Briefly, the samples and reaction solution were mixed and incu-bated at 37 ◦C for 40 min. Coloration solution was added andincubated for 10 min, and absorbance was measured at 550 nmon a microplate reader (TECAN-GENious, Austria). A standardcurve was established using a serial dilution of commercial SOD.The remained pellets were re-suspended in extraction buffer(50 mM hydroxyethyl piperazine ethanesulfonic acid containing0.5% cetyltrimethyl ammonium bromide) and subjected to threefreeze-thaw cycles. The homogenate was centrifuged at 13,000 × gfor 15 min at 4 ◦C. The supernatants generated were assayed forMPO activity. MPO activity was measured by a MPO determinationkit using commercially available reagents, according to the man-ufacturer’s instructions. Briefly, the samples containing MPO wereincubated in a 50 mM sodium phosphate buffer containing 1.5 M

hydrogen peroxide and 0.167 mM O-dianisidine dihydrochloridefor 30 min. Absorbance was measured at 460 nm on a microplatereader (TECAN-GENious, Austria). A standard curve was establishedusing a serial dilution of commercial MPO. SOD and MPO activitieswere expressed as units per milligram of protein.

3 harmacology 130 (2010) 392–397

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Fig. 2. Effect of Taraxacum officinale (TO) on number of total cells and neutrophils inBALF of LPS-induced ALI mice. Mice were administered with TO (2.5, 5 and 10 mg/kg)

94 L. Liu et al. / Journal of Ethnop

.9. Histopathological examination of lung

The left lung was harvested and fixed in 10% buffered formalinor 24 h, dehydrated, embedded in paraffin, and then stained withematoxylin–eosin (H&E) and observed by light microscopy.

.10. Cytokine analysis

The levels of cytokine TNF-� and IL-6 in the supernatants ofhe BALF were quantified in duplication by a sandwich ELISA kitsing commercially available reagents, according to the manufac-urer’s instructions. Briefly, microwell plates were coated overnightt 4 ◦C with mouse TNF-� or IL-6 capture antibody, and blockedt room temperature for 1 h with 1% BSA in phosphate-bufferedaline (PBS) with shaking. Samples from the BALF of LPS-inducedice and internal standard were incubated at room temperature

or 2 h with shaking, followed by mouse TNF-� or IL-6 biotinylatedetection antibody for 1 h and an avidin horseradish peroxidaseAv-HRP) conjugate for 30 min. TMB substrate solution was addednd incubated in the dark for 15 min. The reaction was stoppedy the addition of 1 M H2SO4 and absorbance was measured at50 nm on a microplate reader (TECAN-GENious, Austria). The lev-ls of TNF-� and IL-6 were expressed as picograms per milliliter ofALF based on the appropriate standard curve.

.11. Statistical analysis

All values are expressed as means ± SEMs. Statistical analy-is was performed using one-way ANOVA followed by a multipleomparison test (post hoc Tukey test). Statistical significance wasccepted at P < 0.05.

. Results

.1. Effects of Taraxacum officinale on LPS-induced lung W/D

atio and protein concentration in BALF

The lung W/D ratio and the total protein concentration in theALF were evaluated at 24 h after LPS challenge. As shown inig. 1, the lung W/D ratio and the total protein concentration in

ig. 1. Effects of Taraxacum officinale (TO) on the lung W/D ratio and total proteinoncentration of BALF in LPS-induced ALI mice. Mice were administered with TO2.5, 5 and 10 mg/kg) and DXM (2 mg/kg) as described in Section 2. The lung W/Datio (A) and total protein concentration in BALF (B) were determined at 24 h afterPS challenge. Data represent means ± SEMs (n = 5 or 6 in each group). #P < 0.05 vs.ontrol group; *P < 0.05, **P < 0.01 vs. LPS group.

and DXM (2 mg/kg) as described in Section 2. BALF was collected at 24 h followingLPS challenge to measure the number of total cells (A) and neutrophils (B). Datarepresent the means ± SEMs (n = 5 or 6 in each group). #P < 0.05, ##P < 0.01 vs. controlgroup; *P < 0.05, **P < 0.01 vs. LPS group.

the BALF were found to be significantly higher after LPS challengecompared with those of the control group (P < 0.05 or P < 0.01).Taraxacum officinale was found to decrease the lung W/D ratio andthe total protein concentration in a dose-dependent manner. Tarax-acum officinale at 10 mg/kg significantly decreased the lung W/Dratio (P < 0.05) (Fig. 1A). Taraxacum officinale at 5 and 10 mg/kg sig-nificantly decreased the total protein concentration in the BALF(P < 0.05) (Fig. 1B). DXM also significantly decreased the lung W/Dratio (P < 0.05) and the total protein concentration (P < 0.01).

3.2. Effect of Taraxacum officinale on LPS-induced inflammatorycell counting in BALF

The total cell counts and neutrophil counts in the BALF wereevaluated at 24 h after LPS challenge. As shown in Fig. 2, exposure toLPS significantly increased the number of total cells and neutrophilscompared with the control group (P < 0.01). However, Taraxacumofficinale and DXM significantly reduced the number of total cellsand neutrophils in a dose-dependent manner (P < 0.05 or P < 0.01).

3.3. Effect of Taraxacum officinale on LPS-induced SOD and MPOactivities in lung tissues

Oxidative stress plays an important role in the developmentof LPS-induced ALI. To evaluate the effects of Taraxacum offici-nale on oxidative stress, SOD and MPO activities in the lungs weredetermined at 24 h after LPS challenge. As shown in Fig. 3, LPSchallenge resulted in significant decreases of SOD activity and sig-nificant increases of MPO activity in the lungs compared with thecontrol group (P < 0.05). However, Taraxacum officinale at 5 and10 mg/kg significantly increased SOD activity (P < 0.05) (Fig. 3A) anddecreased LPS-induced MPO activity in the lungs (P < 0.05) (Fig. 3B)in a dose-dependent manner. DEX also significantly increased SODactivity and decreased MPO activity in the lungs (P < 0.05).

3.4. Effect of Taraxacum officinale on LPS-inducedhistopathological change in lung tissues

The effect of Taraxacum officinale on the lungs of mice was deter-mined at 24 h after LPS challenge by histochemical staining with

L. Liu et al. / Journal of Ethnopharmacology 130 (2010) 392–397 395

Fig. 3. Effects of Taraxacum officinale (TO) on SOD and MPO activities of lung tissuein LPS-induced ALI mice. Mice were administered with TO (2.5, 5 and 10 mg/kg) andDaMv

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Fig. 5. Effect of Taraxacum officinale (TO) on production of inflammatory cytokineTNF-� and IL-6 in BALF of LPS-induced ALI mice. Mice were administered with TO

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XM (2 mg/kg) as described in Section 2. Lung homogenates were prepared at 24 hfter LPS challenge. SOD and MPO activities were determined by mouse SOD andPO ELISA kits. Data present the means ± SEMs (n = 5 or 6 in each group). #P < 0.05

s. control group; *P < 0.05 vs. LPS group.

&E. Normal pulmonary histology was found in the control groupFig. 4A). The lungs of mice exposed to LPS showed significantro-inflammatory alterations characterized by lung edema, alve-lar hemorrhage, inflammatory cell infiltration, and destruction ofpithelial and endothelial cell structure (Fig. 4B). In contrast, Tarax-cum officinale and DXM ameliorated many of the symptoms of ALIFig. 4C and D).

.5. Effect of Taraxacum officinale on TNF-˛ and IL-6 productionn BALF

The effect of Taraxacum officinale on TNF-� and IL-6 productionn the BALF was analyzed at 6 h after LPS challenge by ELISA. Ashown in Fig. 5, LPS significantly increased TNF-� and IL-6 pro-uction compared with the control group (P < 0.01). Taraxacum

ig. 4. Effect of Taraxacum officinale on lung histopathological change in LPS-induced ALIand 10 mg/kg) and DXM (2 mg/kg) as described in Section 2. Lungs (n = 3) were proces

roup, (C) LPS + Taraxacum officinale group, and (D) LPS + DXM group. The arrows indicate

(2.5, 5 and 10 mg/kg) and DXM (2 mg/kg) as described in Section 2. BALF was col-lected at 6 h following LPS challenge to analyze TNF-� (A) and IL-6 (B) levels. Datapresent the means ± SEMs (n = 5 or 6 in each group). #P < 0.05, ##P < 0.01 vs. controlgroup; *P < 0.05, **P < 0.01 vs. LPS group.

officinale at 10 mg/kg significantly reduced TNF-� production in theBALF (P < 0.05) (Fig. 5A), Taraxacum officinale at 5 and 10 mg/kg sig-nificantly reduced IL-6 production in the BALF (P < 0.05) (Fig. 5B).DXM also significantly inhibited TNF-� (P < 0.01) and IL-6 produc-tion (P < 0.05).

4. Discussion

LPS is a principle component of the outer membrane of Gram-

negative bacteria, and plays a key role in eliciting an inflammatoryresponse (Saluk-Juszczak and Wachowicz, 2005). It is an importantinducer of lung injury which can be employed in the investigationof ALI (Kitamura et al., 2001; Wu et al., 2002). The etiologies andmechanisms of ALI have been extensively investigated in various

mice (×100, H&E staining). Mice were administered with Taraxacum officinale (2.5,sed for histological changes at 24 h after LPS challenge. (A) Control group, (B) LPSproduced prominent neutrophils infiltration and alveolar hemorrhage.

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xperimental models. In our study, an animal model of direct ALIas established and used by i.n. instillation of LPS in mice. Thisethod causes pulmonary inflammation as an acute injury that

ccurs after 2–4 h and maximizes at 24–48 h (Szarka et al., 1997).he development of an ALI model by way of LPS i.n. instillation isell suited for preliminary pharmacological studies of new drugs

r other therapeutic agents because i.n. instillation of LPS into micean produce an controlled ALI without causing systemic inflamma-ion and multi-organ failure (Szarka et al., 1997; Kitamura et al.,001; Wu et al., 2002). Glucocorticoids have been used to allevi-te respiratory failure due to the damage caused by neutrophilicranulocyte and alveolar macrophages in their metabolically acti-ated states (von Bismarck et al., 2009), and are the most frequentlysed anti-inflammatory drugs in the clinical treatment of ALI/ARDSMeduri et al., 2002). Therefore, DXM was used as a positive controlo evaluate the anti-inflammatory efficiency of Taraxacum offici-ale in LPS-induced ALI. In the present study, for the first time, wexplored the effect of Taraxacum officinale on LPS-induced ALI inice. The data presented here demonstrate that Taraxacum offic-

nale exerts potent anti-inflammatory effects in mice during ALInduced by LPS.

Edema is a typical symptom of inflammation not only in sys-emic inflammation, but also in local inflammation. To quantify the

agnitude of pulmonary edema, we first evaluated the lung W/Datio. Here, we found that Taraxacum officinale decreased the lung

/D ratio, which indicates that Taraxacum officinale could inhibithe leakage of serous fluid into lung tissue and attenuate the devel-pment of pulmonary edema. As another index of ALI by LPS, weeasured the total protein content in the BALF, which indicates

pithelial permeability and pulmonary edema (Beck et al., 1982).s expected, mice exposed to LPS presented with a high proteinontent in the BALF. LPS-induced increases in total protein in theALF were inhibited by Taraxacum officinale.

In ALI, the predominant inflammatory cells are neutrophils,hich play an important role in the development of most cases

f ALI and are considered to be central to the pathogenesis ofLI/ARDS (Abraham, 2003; Cepkova and Matthay, 2006). A delay ineutrophil apoptosis may exacerbate organ dysfunction by extend-

ng the function of neutrophils at sites of inflammation, includinghe injured lung (Fujishima and Aikawa, 1995). As expected, micexposed to LPS exhibited a massive recruitment of inflammatoryells including neutrophils in the airways. In contrast, treatmentith Taraxacum officinale inhibited the LPS-induced increase inumber of total cells and neutrophils in the BALF. Consistent withistological analysis of the lung, there was substantial infiltrationf neutrophils in mice with LPS-induced ALI; Taraxacum officinaleuccessfully abated lung inflammation and reduced tissue neu-rophilia, this corroborated our findings in the BALF. These findingsonfirm that the protective effect of Taraxacum officinale on ALInduced by LPS is related to an attenuation of inflammatory cellequestration and migration into the lung tissue.

MPO is an enzyme located mainly in the primary granules ofeutrophils, thus MPO activity in the parenchyma reflects the adhe-ion and margination of neutrophils in the lung (Klebanoff, 2005).eutrophils excrete MPO in the extracellular medium, bringingbout an accumulation of HOCl and several other reactive oxygenerivatives and leading to an oxidative modification of proteinsr cellular structures (van Antwerpen et al., 2007). The presenttudy showed that LPS induced a significant enhancement of MPOctivity in mouse lung parenchyma after LPS challenge in com-arison to control mice, indicating a significant recruitment of

eutrophils in lung parenchyma. Taraxacum officinale inhibitedulmonary parenchymal MPO activity and was consistent withecreased number of neutrophils in the BALF, suggesting a mecha-ism by which Taraxacum officinale inhibited LPS-induced ALI. SOD

s an enzyme that exists in cells removing oxyradicals, whose activ-

acology 130 (2010) 392–397

ity variation may represent degree of tissue injury (Macarthur et al.,2000). In this study, Taraxacum officinale enhanced SOD activity,suggesting Taraxacum officinale may effectively scavenge oxyradi-cals during the inflammatory response to LPS-induced ALI.

LPS is known to induce the production of several inflammatoryand chemotactic cytokines. Pro-inflammatory cytokines TNF-� andIL-6 appear in the early phase of an inflammatory response, playa critical role in the pathophysiology of inflammation in ALI, andcontribute to the severity of lung injury (Giebelen et al., 2007).Many sequelae associated with ALI result from excessive produc-tion of cytokines (such as TNF-� and IL-6) by activated monocytes(Ward, 1996). High levels of TNF-� and IL-6 in the BALF have beennoted in patients with ALI/ARDS, and the persistent elevation ofpro-inflammatory cytokines in humans with ALI or sepsis has beenassociated with more severe outcomes (Minamino and Komuro,2006). In the present study, we found that LPS induced the pro-duction of large amounts of TNF-� and IL-6 in the BALF of mice;Taraxacum officinale downregulated TNF-� and IL-6 secretion at6 h after LPS challenge. Therefore, Taraxacum officinale may pro-tect against LPS-induced ALI by decreasing the production of thesepro-inflammatory cytokines.

Several major families of compounds were present in Tarax-acum officinale and may play a role in the anti-inflammatoryactivity: triterpenes (arnidiol, faradiol), phytosterols (taraxasterol,�-taraxasterol, stigmasterol, and �-sitosterol), phenolic acids (caf-feic acid, p-coumaric acid, chlorogenic acid, quinic acid, andtartaric acid) and flavonoids (luetolin-7-O-glucoside, luetolin-4′-O-glucoside, chrysoeriol, luteolin, quercetin glycosides, andluetolin-7-O-rutinoside) (Schütz et al., 2006). Previous studies haveshown that two flavonoid compounds, luteolin and luteolin-7-O-glucoside, rich in the ethyl acetate fraction of Taraxacum officinalesuppress production of nitric oxide (NO) and prostaglandin E2 inLPS-activated RAW 264.7 macrophage cells (Hu and Kitts, 2004).Taraxacum officinale extract has also been found to inhibit produc-tion of TNF-� by inhibiting IL-1 production in primary culturesof rat astrocytes stimulated with LPS and substance P, indicatingan anti-inflammatory activity of Taraxacum officinale in the centralnervous system (Kim et al., 2000). The water extract of Taraxacumofficinale contains many bioactive compounds. However, up to now,we do not know which compounds are responsible for the protec-tive effect on ALI. Thus, it will be important to perform additionalexperiments to identify the efficient compounds from Taraxacumofficinale. We are currently separating Taraxacum officinale extractand testing their anti-inflammatory activity.

In conclusion, our study shows that Taraxacum officinale hasa protective effect on LPS-induced ALI. Pretreatment with Tarax-acum officinale reduces lung W/D ratio, protein leakage in the BALF,inflammatory cell infiltration into lung tissue, and MPO activityand enhances SOD activity. Histological examination also showsthat Taraxacum officinale has a significant anti-inflammatory activ-ity during LPS-induced ALI. Moreover, we found that the protectionof Taraxacum officinale may be related to its ability to regulate pro-inflammatory cytokine production.

Acknowledgment

This work was supported by a grant from the Department ofEducation of Jilin Province (No. 2008007).

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