Zu-Qing Su

Usnic acid protects LPS-induced acute lung injury in mice through attenuating inflammatory responses and oxidative stress

Usnic acid is a dibenzofuran derivative found in several lichen species, which has been shown to possess several activities, including antiviral, antibiotic, antitumoral, antipyretic, analgesic, antioxidative and anti-inflammatory activities. However, there were few reports on the effects of usnic acid on LPS-induced acute lung injury (ALI). The aim of our study was to explore the effect and possible mechanism of usnic acid on LPS-induced lung injury. In the present study, we found that pretreatment with usnic acid significantly improved survival rate, pulmonary edema. In the meantime, protein content and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) significantly decreased, and the levels of MPO, MDA, and H2O2 in lung tissue were markedly suppressed after treatment with usnic acid. Meanwhile, the activities of SOD and GSH in lung tissue significantly increased after treatment with usnic acid. Additionally, to evaluate the anti-inflammatory activity of usnic acid, the expression of pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and anti-inflammatory cytokine IL-10, and chemokines interleukin-8 (IL-8) and macrophage inflammatory protein-2 (MIP-2) in BALF were studied. The results in the present study indicated that usnic acid attenuated the expression of TNF-α, IL-6, IL-8 and MIP-2. Meanwhile, the improved level of IL-10 in BALF was observed. In conclusion, these data showed that the protective effect of usnic acid on LPS-induced ALI in mice might relate to the suppression of excessive inflammatory responses and oxidative stress in lung tissue. Thus, it was suggested that usnic acid might be a potential therapeutic agent for ALI.

Protective effects of pogostone from Pogostemonis Herba against ethanol-induced gastric ulcer in rats

We examined the protective effect of pogostone (PO), a chemical constituent isolated from Pogostemonis Herba, on the ethanol-induced gastric ulcer in rats. Administration of PO at doses of 10, 20 and 40 mg/kg body weight prior to ethanol ingestion effectively protected the stomach from ulceration. The gastric lesions were significantly ameliorated by all doses of PO as compared to the vehicle group. Pre-treatment with PO prevented the oxidative damage and the decrease of prostaglandin E2 (PGE2) content. In addition, PO pretreatment markedly increased the mucosa levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT), and decreased gastric malonaldehyde (MDA), relative to the vehicle group. In the mechanistic study, significant elevation of non-protein-sulfhydryl (NP-SH) was observed in the gastric mucosa pretreated by PO. Analysis of serum cytokines indicated that PO pretreatment obviously elevated the decrease of interleukin-10 (IL-10) level, while markedly mitigated the increment of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) secretions in ethanol-induced rats. Taken together, these results strongly indicate that PO could exert a gastro-protective effect against gastric ulceration, and the underlying mechanism might be associated with the stimulation of PGE2, improvement of antioxidant and anti-inflammatory status, as well as preservation of NP-SH.

Gastroprotective effect of andrographolide sodium bisulfite against indomethacin-induced gastric ulceration in rats.

Andrographolide sodium bisulfite (ASB), a water-soluble sulfonate of andrographolide has been shown to possess anti-inflammatory, antipyretic and analgesic activities. However, there is no report on the gastroprotective effect of ASB against indomethacin-induced gastric ulcer. Here we investigated the possible anti-ulcerogenic potential of ASB and the underlying mechanism against indomethacin-induced gastric ulcer in rats. The ulcer area, histopathological assessment, contents of gastric mucosal glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), malonaldehyde (MDA) and prostaglandin E2 (PGE2) were examined. In addition, cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) mRNA expression and immunohistochemical evaluation of HSP70, Bcl-2 and Bax proteins were also investigated. Results indicated that ASB pre-treatment significantly reduced the ulcer areas induced by indomethacin compared with the vehicle group. The gastric levels of GSH, CAT and SOD were markedly increased by ASB while the level of MDA was decreased. In addition, ASB pretreatment significantly promoted the gastric PGE2 levels and up-regulated the COX-1 and COX-2 mRNA expression in comparison with the vehicle group. Immunohistochemistry analysis showed obvious up-regulation of HSP70 and Bcl-2 protein expression while suppression of Bax protein in the gastric tissue of ASB-pretreated group. Taken together, these findings indicated that the gastroprotective effect of ASB might be associated with the improvement of antioxidative status, activation of COX-mediated PGE2 synthesis, down-regulation of Bax proteins and up-regulation of Bcl-2 and HSP70 proteins. ASB might have the potential for further development as a promising alternative for antiulcer treatment.

Inactivation of jack bean urease by scutellarin: Elucidation of inhibitory efficacy, kinetics and mechanism

In the present study, the inactivation effect of scutellarin (SL) on jack bean urease was investigated to elucidate the inhibitory potency, kinetics and mechanism of inhibition. It was revealed that SL acted as a concentration- and time-dependent inactivator of urease characteristic of slow-binding inhibition with an IC50 of 1.35±0.15 mM. The rapid formation of the initial SL-urease complex with an inhibition constant of Ki=5.37×10(-2) mM was followed by a slow isomerization into the final complex with the overall inhibition constant of Ki*=3.49×10(-3) mM. High effectiveness of thiol protectors, such as L-cysteine (L-cys), 2-mercaptoethanol (2-ME) and dithiothreitol (DTT) significantly slowed down the rate of inactivation, indicating the strategic role of the active site sulfhydryl group in the blocking process. While the insignificant protection by boric acid and fluoride from the inactivation further confirmed that the active site cysteine should be obligatory for urease inhibition, which was also rationalized by the molecular docking study. The inhibition of SL on urease proved to be reversible since SL-blocked urease could be reactivated by DTT application and multidilution. The results obtained indicated that urease inactivation resulted from the reaction between SL and the sulfhydryl group.

Protective effects of pogostone against LPS-induced acute lung injury in mice via regulation of Keap1-Nrf2/NF-κB signaling pathways.

Pogostone, a major component of Pogostemon cablin, has been demonstrated to possess antibacterial, anti-fungal, immunosuppressive and anti-inflammatory properties. To investigate the potential therapeutic effect of pogostone on lipopolysaccharide (LPS)-induced acute lung injury (ALI), mice were pretreated with pogostone prior to LPS exposure. After LPS challenge, the lungs were excised and the histological changes, wet to dry weight ratios, MPO activity reflecting neutrophil infiltration, and MDA activity reflecting oxidative stress were examined. The inflammatory cytokines in the BALF were determined by ELISA assay. Moreover, the expressions of p65 and phosphorylated p65 subunit of NF-κB, and Nrf2 in the nucleus in lung tissues were measured by Western blot analysis, and meanwhile the dependent genes of NF-κB and Nrf2 were assessed by RT-qPCR. The results showed that pretreatment with pogostone markedly improved survival rate, attenuated the histological alterations in the lung, reduced the MPO and MDA levels, decreased the wet/dry weight ratio of lungs, down-regulated the level of pro-inflammatory mediators including TNF-a, IL-1β and IL-6. Furthermore, pretreatment with pogostone enhanced the Nrf2 dependent genes including NQO-1, GCLC and HO-1 but suppressed NF-κB regulated genes including TNF-α, IL-1β and IL-6. The mechanism behind the protective effect was correlated with its regulation on the balance between Keap1-Nrf2 and NF-κB signaling pathways. Therefore, pogostone may be considered as a potential therapeutic agent for preventing and treating ALI.

The gastroprotective effect of pogostone from Pogostemonis Herba against indomethacin-induced gastric ulcer in rats.

Pogostemonis Herba, known as “Guang-Huo-Xiang” in Chinese, has been widely used in the treatment of gastrointestinal dysfunction. Pogostone is one of the major constituents of Pogostemonis Herba. The aim was to scientifically evaluate the possible gastroprotective effect and the underlying mechanisms of pogostone against indomethacin-induced gastric ulcer in rats. Rats were orally treated with vehicle, lansoprazole (30 mg/kg) or pogostone (10, 20 and 40 mg/kg) and subsequently exposed to acute gastric lesions induced by indomethacin. Gross evaluation, histological observation, gastric mucosal superoxide dismutase activity, glutathione content, catalase activity, malonaldehyde level and prostaglandin E2 production were performed. Immunohistochemistry and reverse transcription polymerase chain reaction for cyclooxygenase-1 and cyclooxygenase-2, as well as terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, immunohistochemistry for heat-shock protein 70, B-cell lymphoma-2 and Bax were conducted. Results indicated that rats pretreated with pogostone showed remarkable protection from the gastric mucosa damage compared to vehicle-treated rats based on the ulcer index and inhibition percentage. Histologically, oral administration of pogostone resulted in observable improvement of gastric injury, characterized by reduction of necrotic lesion, flattening of gastric mucosa and alleviation of submucosal edema with hemorrhage. Pogostone pretreatment significantly raised the depressed activities of superoxide dismutase, glutathione and catalase, while reduced the elevated malonaldehyde level compared with indomethacin-induced group. Pogostone-pretreated group induced a significant increase in gastric mucosal prostaglandin E2 level and obvious up-regulation of protein levels and mRNA expressions of cyclooxygenase-1 and cyclooxygenase-2. Furthermore, antiapoptotic effect of pogostone was verified by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and the apoptotic process triggered by pogostone involved the up-expression of heat-shock protein70 and B-cell lymphoma-2 protein, and suppression of Bax protein expressions in the ulcerated tissues. It is speculated that the gastroprotective effect of pogostone against indomethacin-induced gastric ulceration might be associated with its stimulation of cyclooxygenase-mediated prostaglandin E2, antioxidant and antiapoptotic effect.

Anti-Inflammatory Property of the Ethanol Extract of the Root and Rhizome of Pogostemon cablin (Blanco) Benth

The aim of this study was to investigate the anti-inflammatory property of the ethanol extract of the root and rhizome of Pogostemon cablin (ERP). The anti-inflammatory effect was evaluated using four animal models including xylene-induced mouse ear edema, acetic acid-induced mouse vascular permeability, carrageenan-induced mouse pleurisy, and carrageenan-induced mouse hind paw edema. Results indicated that oral administration of ERP (120, 240, and 480 mg/kg) significantly attenuated xylene-induced ear edema, decreased acetic acid-induced capillary permeability, inhibited carrageenan-induced neutrophils recruitment, and reduced carrageenan-induced paw edema, in a dose-dependent manner. Histopathologically, ERP (480 mg/kg) abated inflammatory response of the edema paw. Preliminary mechanism studies demonstrated that ERP decreased the level of MPO and MDA, increased the activities of anti-oxidant enzymes (SOD, GPx, and GRd), attenuated the productions of TNF-α, IL-1β, IL-6, PGE2 and NO, and suppressed the activities of COX-2 and iNOS. This work demonstrates that ERP has considerable anti-inflammatory potential, which provided experimental evidences for the traditional application of the root and rhizome of Pogostemon cablin in inflammatory diseases.

Kinetics and Mechanism Study of Competitive Inhibition of Jack-Bean Urease by Baicalin

Baicalin (BA) is the principal component of Radix Scutellariae responsible for its pharmacological activity. In this study, kinetics and mechanism of inhibition by BA against jack-bean urease were investigated for its therapeutic potential. It was revealed that the IC50 of BA against jack-bean urease was 2.74 ± 0.51 mM, which was proved to be a competitive and concentration-dependent inhibition with slow-binding progress curves. The rapid formation of initial BA-urease complex with an inhibition constant of K i = 3.89 × 10−3 mM was followed by a slow isomerization into the final complex with an overall inhibition constant of K i* = 1.47 × 10−4 mM. High effectiveness of thiol protectors against BA inhibition indicated that the strategic role of the active-site sulfhydryl group of the urease was involved in the blocking process. Moreover, the inhibition of BA was proved to be reversible due to the fact that urease could be reactivated by dithiothreitol but not reactant dilution. Molecular docking assay suggested that BA made contacts with the important activating sulfhydryl group Cys-592 residues and restricted the mobility of the active-site flap. Taken together, it could be deduced that BA was a competitive inhibitor targeting thiol groups of urease in a slow-binding manner both reversibly and concentration-dependently, serving as a promising urease inhibitor for treatments on urease-related diseases.

(-)-Patchouli alcohol protects against Helicobacter pylori urease-induced apoptosis, oxidative stress and inflammatory response in human gastric epithelial cells.

(-)-Patchouli alcohol (PA), the major active principle of Pogostemonis Herba, has been reported to have anti-Helicobacter pylori and gastroprotective effects. In the present work, we aimed to investigate the possible protective effect of PA on H. pylori urease (HPU)-injured human gastric epithelial cells (GES-1) and to elucidate the underlying mechanisms of action. Results showed that pre-treatment with PA (5.0, 10.0, 20.0μM) was able to remarkably ameliorate the cytotoxicity induced by 17.0U/mg HPU in GES-1 cells. Flow cytometric analysis on cellular apoptosis showed that pre-treatment with PA effectively attenuated GES-1 cells from the HPU-induced apoptosis. Moreover, the cytoprotective effect of PA was found to be associated with amelioration of the HPU-induced disruption of MMP, attenuating oxidative stress by decreasing contents of intracellular ROS and MDA, and increasing superoxide dismutase (SOD) and catalase (CAT) enzymatic activities. In addition, pre-treatment with PA markedly attenuated the secretion of nitric oxide (NO) and pro-inflammatory cytokines such as interleukin-2 (IL-2), interleukin-4 (IL-4) and tumor necrosis factor-α (TNF-α), whereas elevated the anti-inflammatory cytokine interleukin-13 (IL-13) in the HPU-stimulated GES-1 cells. Molecular docking assay suggested that PA engaged in the active site of urease bearing nickel ions and interacted with important residues via covalent binding, thereby restricting the active urease catalysis conformation. Our experimental findings suggest that PA could inhibit the cellular processes critically involved in the pathogenesis of H. pylori infection, and its protective effects against the HPU-induced cytotoxicity in GES-1 cells are believed to be associated with its anti-apoptotic, antioxidative, anti-inflammatory and HPU inhibitory actions.

Enhanced anti-tumor activity and reduced toxicity by combination andrographolide and bleomycin in ascitic tumor-bearing mice

Bleomycin (BLM) is an effective anti-carcinogen. With the main detrimental effects of inducing pulmonary fibrosis on patients, its clinical use is limited. Developing agents that enhance the efficacy and attenuate the side effects of cancer chemotherapy are critical. Andrographolide (Andro), an active diterpenoid labdane component extracted from Andrographis panicula, is generally prescribed for treatment of inflammatory associated diseases. The study showed that BLM combined with Andro was significantly more effective than BLM alone on inhibiting the tumor growth, arresting the cell cycle at G0/G1 phase, promoting the capase-3 and capase-8 activity to induce cancer cell apoptosis. The underlying mechanisms may be related to the transcriptional regulation of P53/P21/Cyclin pathways. Moreover, BLM induced pulmonary fibrosis in tumor-bearing mice, but BLM combined with Andro dramatically alleviated the lesion in pulmonary fibrosis by activating the SOD, suppressing MDA and HYP production, in the meanwhile attenuating the IL-1β, TNF- α, IL-6 and TGF-β1 level. These mechanisms were associated with its effect on inhibition of protein expression of TGF-β, α-SMA, p-Smad2/3, enhanced expression of Smad7. Thus, it demonstrated that Andro might be a potential adjuvant therapeutic agent for BLM.