Xiao-Ying Chen

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.

Gastroprotective effect and mechanism of patchouli alcohol against ethanol, indomethacin and stress-induced ulcer in rats

Pogostemonis Herba is an important Chinese medicine widely used in the treatment of gastrointestinal dysfunction. Patchouli alcohol (PA), a tricyclic sesquiterpene, is the major active constituent of Pogostemonis Herba. This study aimed to investigate the possible anti-ulcerogenic potential of PA and the underlying mechanism against ethanol, indomethacin and water immersion restraint-induced gastric ulcers in rats. Gross and histological gastric lesions, biochemical and immunological parameters were taken into consideration. The gastric mucus content and the antisecretory activity were analyzed through pylorus ligature model in rats. Results indicated that oral administration with PA significantly reduced the ulcer areas induced by ethanol, indomethacin and water immersion restraint. PA pretreatment significantly promoted gastric prostaglandin E2 (PGE2) and non-protein sulfhydryl group (NP-SH) levels, upregulated the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) mRNA expression, and considerably boosted the gastric blood flow (GBF) and gastric mucus production in comparison with vehicle. In addition, PA modulated the levels of interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α). The levels of glutathione (GSH), catalase (CAT) and malonaldehyde (MDA) were also restored by PA. However, the gastric secretion parameters (pH, volume of gastric juice and pepsin) did not show any significant alteration. These findings suggest that PA exhibited significant gastroprotective effects against gastric ulceration. The underlying mechanisms might involve the stimulation of COX-mediated PGE2, improvement of antioxidant and anti-inflammatory status, preservation of GBF and NP-SH, as well as boost of gastric mucus production.

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.

Anti-inflammatory activity of β-patchoulene isolated from patchouli oil in mice.

β-Patchoulene (β-PAE) is a tricyclic sesquiterpene isolated from the oil of Pogostemon cablin (patchouli oil), which has been widely used in traditional Chinese medicine for the treatment of inflammatory diseases. However, as one of the major principle of patchouli oil, the biological activity of β-PAE has not been explored so far. In the present study, the anti-inflammatory activity in vivo, and the underlying mechanism, of β-PAE was investigated on experimental mice models of acute inflammation, i.e. xylene-induced ear edema, acetic acid-induced vascular permeability and carrageenan-induced paw edema. The results showed that β-PAE evoked a significant dose-dependent inhibition of ear edema induced by xylene, paw edema induced by carrageenan and suppressed the increase of vascular permeability elicited by acetic acid. Histopathological analysis indicated that β-PAE could markedly decrease the cellular infiltration in paw tissue. β-PAE was also shown to significantly decrease the malondialdehyde (MDA) level and myeloperoxidase (MPO) activity in edema paw. In addition, carrageenan-induced production of some pro-inflammatory cytokines: tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), prostaglandin E2 (PGE2) and nitric oxide (NO), were suppressed in a dose-dependent manner in mice subjected to β-PAE pretreatment, and it also significantly down-regulated the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Further analysis revealed that β-PAE also inhibited the translocation of nuclear factor-κB (NF-κB) from the cytoplasm to the nucleus and stabilize the conversion of nuclear factor-κBα (IκBα) level. These results provided additional chemical and pharmacological basis for the traditional application of P. cablin in inflammatory disorders.

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.

Comparison of Helicobacter pylori Urease Inhibition by Rhizoma Coptidis, Cortex Phellodendri and Berberine: Mechanisms of Interaction with the Sulfhydryl Group

Rhizoma Coptidis, Cortex Phellodendri, and berberine were reported to inhibit Helicobacter pylori. However, the underlying mechanism remained elusive. Urease plays a vital role in H. pylori colonization and virulence. In this work, aqueous extracts of Rhizoma Coptidis, Cortex Phellodendri of different origins, and purified berberine were investigated against H. pylori urease and jack bean urease to elucidate the inhibitory capacity, kinetics, and mechanism. Results showed that berberine was the major chemical component in Rhizoma Coptidis and Cortex Phellodendri, and the content of berberine in Rhizoma Coptidis was higher than in Cortex Phellodendri. The IC50 values of Rhizoma Coptidis were significantly lower than those Cortex Phellodendri and purified berberine, of which Coptis chinensis was shown to be the most active concentration- and time-dependent urease inhibitor. The Lineweaver-Burk plot analysis indicated that the inhibition pattern of C. chinensis against urease was noncompetitive for both H. pylori urease and jack bean urease. Thiol protectors (L-cysteine, glutathione, and dithiothreithol) significantly protected urease from the loss of enzymatic activity, while fluoride and boric acid showed weaker protection, indicating the active-site sulfhydryl group was possibly responsible for its inhibition. Furthermore, the urease inhibition proved to be reversible since C. chinensis-blocked urease could be reactivated by glutathione. The results suggested that the anti-urease activity of Rhizoma Coptidis was superior to that of Cortex Phellodendri and berberine, which was believed to be more likely to correlate to the content of total alkaloids rather than berberine monomer. The concentration- and time-dependent, reversible, and noncompetitive inhibition against urease by C. chinensis might be attributed to its interaction with the sulfhydryl group of the active site of urease.

White Pepper and Piperine Have Different Effects on Pharmacokinetics of Puerarin in Rats

This study attempted to explore the effects of white pepper and its major component piperine on puerarin administered to rats. Pharmacokinetic parameters of puerarin in rats were determined by oral administration (400 mg/kg) or intravenous injection (40 mg/kg) of puerarin, pretreated with or without white pepper and piperine given orally. Compared to the control group given oral puerarin only, the combined use of piperine (10 or 20 mg/kg) increased the C max of puerarin by 1.30-fold or 1.64-fold and the AUC0–∞ by 133% or 157%, respectively. In contrast, coadministration of white pepper (125 or 250 mg/kg) decreased oral absorption of puerarin to 83% or 74%, respectively. On the other hand, pretreatment with piperine orally did not alter the intravenous pharmacokinetics of puerarin, while the AUC of puerarin after intravenous administration was increased by pretreatment with white pepper. The results indicate that pretreatment with piperine or pepper exerts different effects on pharmacokinetics of puerarin administrated via intragastric and intravenous routes. Therefore, it is suggested that the combined application of piperine or white pepper with puerarin should be carefully monitored for potential diet-drug interactions.

β-Patchoulene from patchouli oil protects against LPS-induced acute lung injury via suppressing NF-κB and activating Nrf2 pathways

Abstract &bgr;‐Patchoulene (&bgr;‐PAE), a tricyclic sesquiterpene isolated from the essential oil of the leaves and stems of Pogostemon cablin (Blanco) Benth., has been reported to have potent anti‐inflammatory activity. The aim of this study was to evaluate the potential protective effect of &bgr;‐PAE on lipopolysaccharide (LPS)‐induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. ALI was induced by intracheal instillation of LPS into lung, and dexamethasone (DEX) was used as a positive control. Results indicated that pretreatment with &bgr;‐PAE significantly decreased the mortality rate of mice and lung W/D weight ratio, ameliorated lung pathological changes as compared to model group. Meanwhile, &bgr;‐PAE pretreatment markedly inhibited the increase of TNF‐&agr;, IL‐6 and IL‐1&bgr; secretions in the bronchoalveolar lavage fluid, and prevented LPS‐induced elevations of MPO activity and MDA level in the lung. Additionally, &bgr;‐PAE pretreatment significantly elevated miR‐146a expression and suppressed the LPS‐induced activation of NF‐&kgr;B and expression of its mediated genes (TNF‐&agr;, IL‐6 and IL‐1&bgr;). &bgr;‐PAE was also observed to markedly upregulate the Nrf2 and HO‐1 expression and activate the antioxidant genes (NQO‐1, GCLC and HO‐1). Taken together, &bgr;‐PAE possessed protective effect against LPS‐induced ALI, which might be associated with its differential regulation of NF‐&kgr;B and Nrf2 activities and up‐regulation of expression of miR‐146a. The results rendered &bgr;‐PAE a promising anti‐inflammatory agent worthy of further development into a pharmaceutical drug for the treatment of ALI. Highlights&bgr;‐PAE significantly decreased the mortality rate of mice and lung W/D weight ratio, ameliorated lung pathological changes.&bgr;‐PAE pretreatment markedly inhibited the increase of TNF‐&agr;, IL‐6 and IL‐1&bgr; secretions in the bronchoalveolar lavage fluid.&bgr;‐PAE prevented LPS‐induced elevations of MPO activity and MDA level in the lung.ß‐PAE possessed protective effect against LPS‐induced ALI by inhibiting NF‐&kgr;B and activating Nrf2 pathways.