Zhi-Zhun Mo

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.

Selective antibacterial activity of patchouli alcohol against Helicobacter Pylori based on inhibition of urease

The aim of this study is to evaluate the antibacterial activity and urease inhibitory effects of patchouli alcohol (PA), the bioactive ingredient isolated from Pogostemonis Herba, which has been widely used for the treatment of gastrointestinal disorders. The activities of PA against selected bacteria and fungi were determined by agar dilution method. It was demonstrated that PA exhibited selective antibacterial activity against Helicobacter pylori, without influencing the major normal gastrointestinal bacteria. Noticeably, the antibacterial activity of PA was superior to that of amoxicillin, with minimal inhibition concentration value of 78 µg/mL. On the other hand, PA inhibited ureases from H. pylori and jack bean in concentration‐dependent fashion with IC50 values of 2.67 ± 0.79 mM and 2.99 ± 0.41 mM, respectively. Lineweaver‐Burk plots indicated that the type of inhibition was non‐competitive against H. pylori urease whereas uncompetitive against jack bean urease. Reactivation of PA‐inactivated urease assay showed DL‐dithiothreitol, the thiol reagent, synergistically inactivated urease with PA instead of enzymatic activity recovery. In conclusion, the selective H. pylori antibacterial activity along with urease inhibitory potential of PA could make it a possible drug candidate for the treatment of H. pylori infection. Copyright

Epiberberine, a natural protoberberine alkaloid, inhibits urease of Helicobacter pylori and jack bean: Susceptibility and mechanism

Abstract In our previous study, Rhizoma Coptidis extract was found to exert more potent inhibitory effect than its major component berberine towards urease from Helicobacter pylori (HPU) and jack bean (JBU). In continuation of our work, the present study was designed to further comparatively investigate the urease inhibitory activities of five major protoberberine alkaloids in Rhizoma Coptidis, namely berberine, palmatine, coptisine, epiberberine, jateorhizine to identify the bioactive constituent, and illuminate the potential mechanism of action. Results indicated that the five protoberberine alkaloids acted as concentration‐dependent inactivators of urease with IC50 values ranging between 3.0 and 5087 &mgr;M for HPU and 2.3–> 10,000 &mgr;M for JBU, respectively. Notably, epiberberine (EB) was found to be the most potent inhibitor against both ureases with IC50 values of 3.0 ± 0.01 &mgr;M for HPU and 2.3 ± 0.01 &mgr;M for JBU, which was more effective than the standard urease inhibitor, acetohydroxamic acid (83 ± 0.01 &mgr;M for HPU and 22 ± 0.01 &mgr;M for JBU, respectively). Further kinetic analysis revealed that the type of EB inhibition against HPU was slow‐binding and uncompetitive, with Ki of 10.6 ± 0.01 &mgr;M, while slow‐binding and competitive against JBU with Ki of 4.6 ± 0.01 &mgr;M. Addition of thiol reagents, such as l‐cysteine, glutathione and dithiothreitol, significantly abolished the inhibition, while Ni2+ competitive inhibitors, boric acid and sodium fluoride, synergetically inhibited urease with EB, indicating the obligatory role of the active site sulfhydryl group for the inhibition. In addition, binding of EB with the urease proved to be reversible, as about 65% and 90% enzymatic activity of HPU and JBU, respectively, could be restored by dithiothreitol application. These findings highlighted the potential role of Rhizoma Coptidis protoberberine alkaloids, especially EB, as a lead urease inhibitor in the treatment of diseases associated with ureolytic bacteria. Thus, EB had good potential for further development into a promising therapeutic approach for the treatment of urease‐related diseases. Graphical Abstract Figure. No Caption available.

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.

Inhibition of Helicobacter pylori and Its Associated Urease by Palmatine: Investigation on the Potential Mechanism

In this paper, we evaluated the anti-Helicobacter pylori activity and the possible inhibitory effect on its associated urease by Palmatine (Pal) from Coptis chinensis, and explored the potential underlying mechanism. Results indicated that Pal exerted inhibitory effect on four tested H. pylori strains (ATCC 43504, NCTC 26695, SS1 and ICDC 111001) by the agar dilution test with minimum inhibitory concentration (MIC) values ranging from 100 to 200 μg/mL under neutral environment (pH 7.4), and from 75 to 100 μg/mL under acidic conditions (pH 5.3), respectively. Pal was observed to significantly inhibit both H. pylori urease (HPU) and jack bean urease (JBU) in a dose-dependent manner, with IC50 values of 0.53 ± 0.01 mM and 0.03 ± 0.00 mM, respectively, as compared with acetohydroxamic acid, a well-known urease inhibitor (0.07 ± 0.01 mM for HPU and 0.02 ± 0.00 mM for JBU, respectively). Kinetic analyses showed that the type of urease inhibition by Pal was noncompetitive for both HPU and JBU. Higher effectiveness of thiol protectors against urease inhibition than the competitive Ni2+ binding inhibitors was observed, indicating the essential role of the active-site sulfhydryl group in the urease inhibition by Pal. DTT reactivation assay indicated that the inhibition on the two ureases was reversible, further supporting that sulfhydryl group should be obligatory for urease inhibition by Pal. Furthermore, molecular docking study indicated that Pal interacted with the important sulfhydryl groups and inhibited the active enzymatic conformation through N-H ∙ π interaction, but did not interact with the active site Ni2+. Taken together, Pal was an effective inhibitor of H. pylori and its urease targeting the sulfhydryl groups, representing a promising candidate as novel urease inhibitor. This investigation also gave additional scientific support to the use of C. chinensis to treat H. pylori-related gastrointestinal diseases in traditional Chinese medicine. Pal might be a potentially beneficial therapy for gastritis and peptic ulcers induced by H. pylori infection and other urease-related diseases.

Chongcao-Shencha Attenuates Liver and Kidney Injury through Attenuating Oxidative Stress and Inflammatory Response in D-Galactose-Treated Mice

The Chongcao-Shencha (CCSC), a Chinese herbal compound formula, has been widely used as food material and medicine for enhancing physical strength. The present study investigated the possible effect of CCSC in alleviating the liver and kidney injury in D-galactose- (D-gal-) treated mice and the underlying mechanism. Mice were given a subcutaneous injection of D-gal (200 mg/kg) and orally administered CCSC (200, 400, and 800 mg/kg) daily for 8 weeks. Results indicated that CCSC increased the depressed body weight and organ index induced by D-gal, ameliorated the histological deterioration, and decreased the levels of ALT, AST, BUN, and CRE as compared with D-gal group. Furthermore, CCSC not only elevated the activities of antioxidant enzymes SOD, CAT, and GPx but also upregulated the mRNA expression of SOD1, CAT, and GPx1, while decreasing the MDA level in D-gal-treated mice. Results of western blotting analysis showed that CCSC significantly inhibited the upregulation of expression of nuclear factor kappa B (NF-κB) p65, p-p65, p-IκBα, COX2, and iNOS and inhibited the downregulation of IκBα protein expression caused by D-gal. This study demonstrated that CCSC could attenuate the liver and kidney injury in D-gal-treated mice, and the mechanism might be associated with attenuating oxidative stress and inflammatory response.