Search

The p-coumaric acid is a phenolic compound present in large quantities in the extract of Baccharis dracunculifolia DC, a Brazilian medicinal plant used to treat gastric ulcer. Given the necessity for finding new chemical components capable of accelerating gastric healing, in this study, the effects of the p-coumaric acid were evaluated in the acetic acid-induced ulcer model in rats, where histological, inflammatory, and oxidative parameters were analyzed. The healing property was also evaluated in the scratch assay on fibroblast cells (L929) and the cytotoxicity of p-coumaric acid was assessed in both L929 and human gastric adenocarcinoma (AGS) cells by MTT assay. The treatment with p-coumaric acid (10 mg/kg, p.o.) for 7 days, twice a day, decreased by 44.6% the acetic acid-induced gastric ulcer compared with the vehicle-treated group. The vehicle control-treated group showed a larger extension of the ulcer base and an extensive damage into the mucosa and submucosa layers, which were mitigated by the treatment with p-coumaric acid. This beneficial effect was also associated with increased levels of mucin and reduced glutathione, decreased amount of lipid hydroperoxides, and increased superoxide dismutase and catalase activities without interfering with the activity of myeloperoxidase in the gastric tissue. The compound promoted the restructuring of the cell monolayer in the scratch test and did not show toxicity in the L929 cell line, while reduced the viability of the AGS, a lineage of human gastric adenocarcinoma. Thus, p-coumaric acid may be considered a natural source for the treatment of gastric ulcers, by reinforcing protective factors of gastric mucosa and by accelerating gastric healing.

Although present in the leaves of Mimosa bimucronata (DC.) and many other medicinal plants commonly used to augment urinary volume excretion, the effects of gallic acid as a diuretic agent remain to be studied. Wistar rats were orally treated with vehicle, hydrochlorothiazide, or gallic acid. The effects of gallic acid in the presence of hydrochlorothiazide, furosemide, amiloride, L-NAME, atropine, and indomethacin were also investigated. Diuretic index, pH, conductivity, and electrolyte excretion were evaluated at the end of the experiment (after 8 or 24 h). Gallic acid induced diuretic and saluretic (Na + and Cl - ) effects, without interfering with K + excretion, when orally given to female and male rats at a dose of 3 mg/kg. These effects were associated with increased creatinine and conductivity values while pH was unaffected by any of the treatments. Plasma Na + , K + , and Cl - levels were not affected by any of the acute treatments. The combination with hydrochlorothiazide or furosemide was unable to intensify the effects of gallic acid when compared with the response obtained with each drug alone. On the other hand, the treatment with amiloride plus gallic acid amplified both diuresis and saluresis, besides to a marked potassium-sparing effect. Its diuretic action was significantly prevented in the presence of indomethacin, a cyclooxygenase inhibitor, but not with the pretreatments with L-NAME or atropine. Although several biological activities have already been described for gallic acid, this is the first study demonstrating its potential as a diuretic agent.

According to the Brazilian folk medicine, the leaves of Plinia edulis (Vell.) Sobral (Myrtaceae), known as cambuca, are indicated in the treatment of gastric disorders. Infusions of P. edulis leaves were previously demonstrated to contain both maslinic (MA) and ursolic acids (UA). Both triterpenes have also been identified in the methanolic extract of peels from P. edulis fruit (MEPPE); however, the antiulcer effects of MEPPE have not yet been studied. This study therefore evaluates the gastroprotective potential of MEPPE, MA, and UA using ethanol/HCl- and indomethacin-induced gastric ulcers in mice. In addition, the in vitro effects of these compounds on the H + , K + -ATPase activity and on the free radical DPPH were measured. When used at concentration of 100 μg/mL, both MEPPE and UA were found to reduce the DPPH radical levels by 78.66 and 60.14%, respectively. However, MA did not reduce DPPH radical levels. Our results illustrated the antiulcer effects of MEPPE, MA, and UA against experimental ulcer models when administered by either the oral or the intraperitoneal routes. In addition, MEPPE reduced the size of ethanol/HCl-induced ulcers in a dose-dependent manner (log half-maximal effective oral dose, LogED 50  = 1.09). Interestingly, UA promoted gastroprotection at lower doses than MA by increasing the production of mucin levels at 692%; however, it does not alter the activity of H + , K + -ATPase. In contrast, both MEPPE and MA, when incubated at concentrations of 10 and 100 μg/mL, inhibited H + , K + -ATPase activity in 61.81, 68.37, 54.04, and 70.45%, respectively. These results confirm that MEPPE, MA, and UA display gastroprotective activity through different modes of action; MA inhibits H + , K + -ATPase activity, whereas UA favour the mucus barrier.

This study evaluated the gastroprotective potential of methanolic extract from fruits of Campomanesia reitziana (MECR) and its isolated chalcone dimethyl cardamonin (DMC). The phenolic compound in the extract, and the free radical scavenging activity of MECR and DMC, were quantified. The gastroprotective activity of MECR (30-300 mg/kg, p.o) and DMC (1 and 3 mg/kg, p.o) was determined by ethanol/HCl-induced gastric ulcers in mice. Histological, histochemical, and biochemical analyses were performed in the ulcerated tissue. MECR showed a high content of phenolic compounds, including DMC, and was able to scavenge DPPH radicals by 29.58% at 1000 μg/mL. However, DCM (1-1000 μg/mL) did not reduce DPPH radicals. Pre-treatment with MECR at doses of 100 and 300 mg/kg reduced the gastric lesions by 35.07 and 79.47%, respectively (ulcerated-vehicle group 10.72 ± 0.88 mm 2 ). Moreover, the extract increased the mucin content by 1044.44% and superoxide dismutase activity by 20.04%, and decreased the lipoperoxide levels by 39.39%, compared to the ulcerated-vehicle group (0.27 ± 0.04 pixels × 10 3 /field; 57.37 ± 1.59 U SOD/mg of protein and 29.57 ± 2.99 mmol LOOH/mg of tissue, respectively). However, MECR did not prevent the depletion of reduced glutathione or the decrease in catalase activity. Pre-treatment with DMC, at 1 and 3 mg/kg, also reduced the gastric ulcers by 53.83 and 52.64%, respectively. In summary, these findings confirm the gastroprotective activity of MECR and DMC, and open an interesting field concerning the gastroprotective potential of dimethyl cardamonin, given its potent antinociceptive and anti-inflammatory activity already described.

Although diuretics have been widely used to treat hypertension along with others cardiovascular and renal disorders, no scientific data have been recorded to support the diuretic properties of Rubus rosaefolius Sm. (Rosaceae), a plant popularly used in Brazil to treat hypertension. Male Wistar rats were orally treated with: vehicle; hydrochlorothiazide; aqueous (AERR) and methanolic (MERR) extracts; dichloromethane (DCM), hexane (HEX) and ethyl acetate (EA) fractions; and the isolated compounds 2α,3β,19α-trihydroxy-urs-12-en-28-oic acid (TUA) and 5-hydroxy-3,6,7,8,4'-pentamethoxyflavone (PMF). At the end of the experiment (after 8 or 24 h), urine volume and other urine or plasma parameters were measured. AERR and MERR, at 100 and 30 mg/kg, respectively, induced diuretic, natriuretic and kaliuretic effect. Additionally, the DCM and HEX, but not EA, at 10 mg/kg, also increased urine volume and Na + and K + excretion. Both active constituents, TUA and PMF, at doses of 1 and 3 mg/kg, showed an augmented diuretic and natriuretic index. While TUA revealed a kaliuretic action, PMF did not interfere with potassium excretion. The compounds increased urinary creatinine, but not urea, levels. TUA was able to decrease calcium excretion, as well as HCTZ, while PMF effect was associated with increased urinary prostaglandin E 2 levels. The non-selective muscarinic receptor antagonist (atropine) prevented TUA-induced diuresis. In addition, indomethacin (a cyclooxygenase inhibitor) and atropine, exhibited the ability to block the diuretic effects prompted by PMF. Our study demonstrates the diuretic effect of extracts, fractions and two natural compounds obtained from R. rosaefolius leaves in rats.

Ethanol is a psychoactive substance highly consumed around the world whose health problems include gastric lesions. Baccharis trimera is used in folk medicine for the treatment of gastrointestinal disorders. However, few studies have evaluated its biological and toxic effects. To validate the popular use of B. trimera and elucidate its possible antiulcerogenic and cytotoxic mechanisms, a hydroethanolic extract of B. trimera (HEBT) was evaluated in models of gastric lesions. Rats and mice were used to evaluate the protective and antiulcerogenic effects of HEBT on gastric lesions induced by ethanol, acetic acid, and chronic ethanol consumption. The effects of HEBT were also evaluated in a pylorus ligature model and on gastrointestinal motility. The LD50 of HEBT in mice was additionally estimated. HEBT was analyzed by nuclear magnetic resonance, and a high-performance liquid chromatography fingerprint analysis was performed. Oral HEBT administration significantly reduced the lesion area and the oxidative stress induced by acute and chronic ethanol consumption. However, HEBT did not protect against gastric wall mucus depletion and did not alter gastric secretory volume, pH, or total acidity in the pylorus ligature model. Histologically, HEBT accelerated the healing of chronic gastric ulcers in rats, reflected by contractions of the ulcer base. Flavonoids and caffeoylquinic acids were detected in HEBT, which likely contributed to the therapeutic efficacy of HEBT, preventing or reversing ethanol- and acetic acid-induced ulcers, respectively. HEBT antiulcerogenic activity may be partially attributable to the inhibition of free radical generation and subsequent prevention of lipid peroxidation. Our results indicate that HEBT has both gastroprotective and curative activity in animal models, with no toxicity.

Green tea is an infusion of unfermented leaves of Camellia sinensis (L.) Kuntze (Theaceae), traditionally used for the treatment of obesity, hypercholesterolemia, and gastric complaints. This study evaluated the mechanisms involved in the gastric ulcer healing of the hydroalcoholic extract from green tea (GEt), its ethyl acetate fraction, (GEAc) and epigallocatechin gallate (EGCG) using the model of acetic acid-induced gastric ulcer in rats. The chronic gastric ulcer was induced by application of 80 % acetic acid on serosal mucosa of rats. After 7 days of oral treatment with GEt and GEAc, the ulcer area, mucin content, inflammatory parameters (MPO and NAG), and antioxidant system (GSH and LOOH levels, SOD and GST activities) were evaluated. In vitro, the scavenging activity of GEt and GEAc were also measured. The antisecretory action was studied on the pylorus ligature method in rats. Oral treatment with GEt and GEAc reduced significantly the gastric ulcer area induced by acetic acid. The gastric ulcer healing was accompanied by increasing of mucin content, restoration of GSH levels and SOD activity, and reduction of MPO and LOOH levels. In addition, GEt and GEAc reduced the DPPH free radicals in vitro. Furthermore, the oral treatment of animals with GEt and GEAc did not alter the gastric acid secretion or cause signs of toxicity. Collectively, these results showed that GEt had a pronounced antiulcer effect, possibly through maintenance of mucin content and reduction of inflammation and oxidative stress. In addition, the compounds present in its ethyl acetate fraction could be responsible for the extract activity.