The essential oil from Baccharis trimera (Less.) DC improves gastric ulcer healing in rats through modulation of VEGF and MMP-2 activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Baccharis trimera (Less.) DC known as "carqueja" in Brazil has been acknowledged as a medicinal plant in folk medicine for the treatment of stomach aches and gastrointestinal disorders. AIM OF THE STUDY: The present study aimed to evaluate the gastroprotective and healing effects of essential oil from B. trimera (EOBT) against gastric ulcer lesions caused by absolute ethanol and acetic acid, respectively, and to identify the mechanism of action of this essential oil in male Wistar rats. MATERIALS AND METHODS: The plant material used to obtain EOBT was collected in the southern region of Brazil and was analyzed by chromatography-mass spectrometry (GCMS) demonstrate its characteristic chemical composition, with carquejyl acetate as its main component. Different doses of EOBT (50, 100, and 200 mg/kg) were administered orally in male Wistar rats as an acute treatment against absolute ethanol-induced gastric lesions. The gastric healing effect of EOBT (100 mg/kg) was evaluated once a day after 7, 10, and 14 days of treatment. After treatment, the stomachs of rats from all groups were collected to measure the lesion area (mm2), the activity of myeloperoxidase (MPO), and the relative expression of caspases -3, -8, -9, cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). The zymography method was used to elucidate the activity of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in the healing action of EOBT. We also analyzed toxicological parameters (body weight evolution and biochemical parameters) that could result after treatment with this essential oil for 14 days. RESULTS: Pretreatment with EOBT (100 and 200 mg/kg) significantly decreased the severity of gastric damage induced by absolute ethanol and decreased MPO activity in gastric tissue. After 10 and 14 days of treatment with EOBT (100 mg/kg) once a day, the lesion area was significantly reduced by 61% and 65.5%, respectively, compared to the negative control group. The gastric healing effect of EOBT was followed by a decrease in the expression of COX-1 compared to that in the negative control group. Notably, treatment with EOBT for 14 days increased the expression of VEGF compared to that using an anti-ulcer drug (lansoprazole). Additionally, analyses of MMP-2 and MMP-9 activities in the gastric mucosa confirmed the accelerated gastric healing effect of EOBT, with a significant decrease in the activity of pro-MMP-2. No sign of toxicity was observed after treatment with EOBT for 14 consecutive days. CONCLUSION: These findings indicated that EOBT was effective in preventing and accelerating ulcer healing by decreasing MPO activity, increasing VEGF expression, and decreasing MMP-2 activity. These actions collectively contribute to the rapid recovery of gastric mucosa following treatment with EOBT, without any observed toxicity.

Hypothermic Effect of Acute Citral Treatment during LPS-induced Systemic Inflammation in Obese Mice: Reduction of Serum TNF-α and Leptin Levels.

Citral is a mixture of monoterpenes present in the essential oil of several plants, such as Cymbopogon citratus and Zingiber officinale, possessing anti-inflammatory, anti-ulcerogenic, and antipyretic actions. We investigated the action of citral on body temperature (Tb) and inflammatory signaling in eutrophic and obese mice during Systemic Inflammation (SI) induced by Lipopolysaccharide (LPS). Thus, we assessed the effect of citral (25, 100, and 300 mg/kg) and ibuprofen in LPS-induced SI in Swiss male mice fed a standard diet (SD) or high-fat diet (HFD) for 12 weeks. Following SI induction, we measured Tb and collected the serum, hypothalamus, and gastric mucosa for biochemical measurements. Acute treatment with citral decreased the Tb of both SD and HFD-fed animals. Citral (300 mg/kg) treatment caused a significantly lower Tb variation in HFD-fed animals than in those fed the SD. Citral reduced peripheral levels of tumor necrosis factor (TNF)-α in SD and HFD mice and decreased serum leptin concentration in HFD mice 90 min after the LPS challenge. Furthermore, citral also reduced interleukin (IL)-6 levels in the hypothalamus of obese mice. In summary, citral effectively reduced Tb during SI by reducing inflammatory mediators with a distinct action profile in HFD mice when compared with SD.

Terminalia catappa L. infusion accelerates the healing process of gastric ischemia-reperfusion injury in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Terminalia catappa L. (Combretaceae), known as "amendoeira da praia" in Brazil, has been recognized as a medicinal plant in folk medicine for the treatment of gastrointestinal disorders and other inflammatory conditions. The present study aimed to investigate the preventive and healing effects of the infusion of leaves of T. catappa (ILTC) against gastric lesions caused by ischemia and reperfusion (I/R) injury and characterize its mechanism of action in the gastric mucosa of rats. MATERIALS AND METHODS: Different doses (30, 100, and 300 mg/kg) of ILTC were orally administered as acute and subacute treatments against I/R-induced gastric lesion in rats. After treatment, the stomach of rats was collected to measure the lesion area, redox parameters malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) and inflammatory parameters myeloperoxidase activity (MPO), interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α). The activities of matrix metalloproteinases 2 and 9 (MMPs 2 and 9) were assessed by zymography method to clarify the mechanisms of the healing acceleration promoted by ILTC. RESULTS: Pretreatment with ILTC (100 mg/kg) was effective in preventing the aggravation of lesions in the acute model by reducing MPO activity by 38% relative to control group, despite the lack of clarity of this action at the macroscopical level at the lesion area (p < 0.05). After three days of treatment with ILTC (30 and 100 mg/kg), this infusion significantly reduced the lesion area by 95% and 89%, respectively, compared the control (p < 0.05). The gastric healing effect of all doses of ILTC was followed by a reduction in MPO activity (decrease by 70-78%). Compared to the negative control, an improvement in gastric healing owing to treatment with ILTC was observed and this was followed by an increase in MMP-2 (20-47%) (p < 0.05). CONCLUSION: Three days of treatment with ILTC could accelerate the healing process in I/R-induced lesions in rats. By decreasing MPO levels, ILTC enabled the action of MMP-2, which led to tissue recovery in the gastric mucosa.

Large-Scale Synonymous Substitutions in Cucumber Mosaic Virus RNA 3 Facilitate Amino Acid Mutations in the Coat Protein.

The effect of large-scale synonymous substitutions in a small icosahedral, single-stranded RNA viral genome on virulence, viral titer, and protein evolution were analyzed. The coat protein (CP) gene of the Fny stain of cucumber mosaic virus (CMV) was modified. We created four CP mutants in which all the codons of nine amino acids in the 5' or 3' half of the CP gene were replaced by either the most frequently or the least frequently used synonymous codons in monocot plants. When the dicot host (Nicotiana benthamiana) was inoculated with these four CP mutants, viral RNA titers in uninoculated symptomatic leaves decreased, while all mutants eventually showed mosaic symptoms similar to those for the wild type. The codon adaptation index of these four CP mutants against dicot genes was similar to those of the wild-type CP gene, indicating that the reduction of viral RNA titer was due to deleterious changes of the secondary structure of RNAs 3 and 4. When two 5' mutants were serially passaged in N. benthamiana, viral RNA titers were rapidly restored but competitive fitness remained decreased. Although no nucleic acid changes were observed in the passaged wild-type CMV, one to three amino acid changes were observed in the synonymously mutated CP of each passaged virus, which were involved in recovery of viral RNA titer of 5' mutants. Thus, we demonstrated that deleterious effects of the large-scale synonymous substitutions in the RNA viral genome facilitated the rapid amino acid mutation(s) in the CP to restore the viral RNA titer.IMPORTANCE Recently, it has been known that synonymous substitutions in RNA virus genes affect viral pathogenicity and competitive fitness by alteration of global or local RNA secondary structure of the viral genome. We confirmed that large-scale synonymous substitutions in the CP gene of CMV resulted in decreased viral RNA titer. Importantly, when viral evolution was stimulated by serial-passage inoculation, viral RNA titer was rapidly restored, concurrent with a few amino acid changes in the CP. This novel finding indicates that the deleterious effects of large-scale nucleic acid mutations on viral RNA secondary structure are readily tolerated by structural changes in the CP, demonstrating a novel part of the adaptive evolution of an RNA viral genome. In addition, our experimental system for serial inoculation of large-scale synonymous mutants could uncover a role for new amino acid residues in the viral protein that have not been observed in the wild-type virus strains.

Effect of an MCM4 mutation that causes tumours in mouse on human MCM4/6/7 complex formation.

It has been reported that a point mutation of minichromosome maintenance (MCM)4 causes mammary carcinoma, and it deregulates DNA replication to produce abnormal chromosome structures. To understand the effect of this mutation at level of MCM2-7 interaction, we examined the effect of the same mutation of human MCM4 on the complex formation with MCM6 and MCM7 in insect cells. Human MCM4/6/7 complexes containing the mutated MCM4 were formed, but the hexameric complex formation was not evident in comparison with those containing wild-type MCM4. In binary expression of MCM4 and MCM6, decreased levels of MCM6 were recovered with the mutated MCM4, compared with wild-type MCM4. These results suggest that this mutation of MCM4 perturbs proper interaction with MCM6 to affect complex formation of MCM4/6/7 that is a core structure of MCM2-7 complex. Consistent with this notion, nuclear localization and MCM complex formation of forcedly expressed MCM4 in human cells are affected by this mutation. Thus, the defect of this mutant MCM4 in interacting with MCM6 may generate a decreased level of chromatin binding of MCM2-7 complex.