Graciela H. Wendel

Antimicrobial activity of Artemisia douglasiana and dehydroleucodine against Helicobacter pylori.

ETHNOPHARMACOLOGICAL RELEVANCE The increasing resistance of Helicobacter pylori to antibiotics demands the search for novel compounds from plant based sources. Artemisia douglasiana Besser is widely used in Cuyo region (Argentina) as folk medicine for the treatment of gastric ailments. AIM OF STUDY Based on our previous studies that Artemisia douglasiana exert cytoprotective actions against ethanol-induced gastric mucosal injury we assayed the anti-Helicobacter pylori effect of the Artemisia douglasiana extract and its active compound, dehydroleucodine. MATERIALS AND METHODS The in vitro anti-bacterial activity of Artemisia douglasiana extract and its active compound, dehydroleucodine were determined against one standard strain and six clinical isolates of Helicobacter pylori by using the agar dilution methods. RESULTS The results showed that both dehydroleucodine and Artemisia douglasiana extract had activity against the microorganism with MICs between 1-8 and 60-120 mg/L, respectively. CONCLUSIONS Artemisia douglasiana may be a useful alternative treatment strategy principally in eradication of metronidazole and clarithromycin-resistant strain.

Reduction in voluntary ethanol intake following repeated oral administration of Jodina rhombifolia lyophilized aqueous extract in male Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE The leaves of Jodina rhombifolia (Hook. & Arn.) Reissek (SANTALACEAE) is utilized in Argentine folk medicine for the treatment of alcoholism. AIM OF THE STUDY To evaluate the antialcoholic activity of Jodina rhombifolia lyophilized aqueous extract (JRLE) in male Wistar rats. MATERIALS AND METHODS Rats were housed individually in standard plastic cages with wood chip bedding. Throughout the duration of experiment, ethanol was offered in the standard home-cage; two-bottle free-choice regimen between an ethanolic solution (20% in tap water, v/v) and tap water with unlimited access for 24h per day for 10 consecutive days. Rats were administrated intragastrically twice daily (1 ml/200 g) for 10 consecutive days, with the control vehicle (distilled water) or one of the doses of JRLE (125, 250 and 500 mg/Kg weight). Body weight, ethanol, water and food intake were measured every day at the same hour during the 10 days of experimentation. RESULTS The reducing effect of JRLE on daily ethanol intake was evidenced from the first day of treatment and persisted throughout the entire treatment period. The treatment did not significantly affect daily water intake neither the body weight gain. Daily food intake was higher in rat groups treated with JRLE. CONCLUSION The results obtained in the present preliminary study show that repeated administration of JRLE, markedly reduces ethanol voluntary intake in male Wistar rats. The reduction of consumption was of remarkable magnitude and stable during the treatment 10-days.

Effect of dehydroleucodine on intestinal transit: structural basis of the interaction with the α(2)-adrenergic receptor.

The activity of dehydroleucodine, a sesquiterpene lactone obtained from Artemisia douglasiana, was studied in mice small intestinal transit. Its mechanism was evaluated in the presence of several adrenergic and cholinergic antagonist drugs and one opioid antagonist. Docking of dehydroleucodine into the homology model of the α2-adrenergic receptor allowed us to analyze the structural basis of their interactions. The experiments showed that dehydroleucodine delayed intestinal transit. The docking of dehydroleucodine showed a unique binding site, equivalent to the binding site of carozolol in the β-adrenergic receptor. The results suggested that dehydroleucodine produced an inhibitory effect on intestinal transit. Its action could be mediated, at least in part, through the α2-adrenergic receptor.

Records of Medicinal Plants Utilized as Gastroprotective and for Treatment of Gastrointestinal Ulcers, Gastritis, and Heartburn in Argentina: A Survey of the Literature

Traditional knowledge available on 148 plant species used in Argentina for gastroprotection and treating gastrointestinal ulcers, gastritis, and heartburn, was compiled to analyze their taxonomic grouping, floristic richness, the life form, and organs used, and to determine their susceptibility to over-collection.

Intrarectal Dehydroleucodine Suppresses Trinitrobenzene Sulfonic Acid–Induced Colitis in Rats, A Model for Inflammatory Bowel Disease

Abstract Dehydroleucodine (DhL), isolated from Artemisia douglasiana. Besser (Asteraceae), prevents damage in acetic acid–induced colitis in rats. The trinitrobenzene sulfonic acid (TNBS)-induced model of chronic inflammation of the rat colon was used to determine the efficacy of DhL, at dose of 40 mg/kg, administered in enema form. All rats were sacrificed on day 7 and the colon excised, weighed, and rated macroscopically. Sections of colon were processed for light microscopy. Macroscopic scoring showed a decrease (p < 0.001) in the degree of damage in the DhL group compared with the group of rats treated with TNBS. Colon mass decreased (p < 0.05) in the DhL group compared with the TNBS group. Treatment with DhL resulted in a reduction in the incidence of diarrhea. Light-microscopic examination revealed preservation of mucosal architecture in the DhL-treated rats. DhL had an effective healing capacity at both macroscopic and microscopic levels. We conclude that DhL decreases injury and/or promotes healing in this model.

Cytoprotective Activity of Minor Constituents of Artemisia Douglasiana

Abstract 3α-Hydroxycarvotagenone and its epimer 3β-hydroxy carvotagenone were isolated as a minor mixture and its structure determined by spectral means. The mixture was then used in cytoprotection experiments. The mixture, in spite of possessing a Michael acceptor, did not show cytoprotective activity. The lack of activity was attributed to the presence of a -OH group next to the β-carbon of the Michael acceptor. This -OH group could react in a intramolecular way yielding an epoxide which would produce the inhibition of the Michael acceptor. In order to confirm this, the mixture was acetylated and the mixture of acetates used in our cytoprotection experiments. The mixture of acetates showed a moderate but significant cytoprotection probing the existence of some kind of stereoelectronic interaction between the acceptor and the nucleophile.

Antidiarrhoeal activity of Aristolochia argentina Gris. (Aristolochiaceae) in rodents

The roots of Aristolochia argentina are used in folk medicine for the treatment of colitis, diarrhoea and hemorrhoids. In this study, based on ethnobotanical lead, we evaluated the antidiarrhoeal activity of Aristolochia argentina lyophilized aqueous extract (AALE) in rats and mice using various models. The castor oil and magnesium sulphate induced diarrhoea, the small intestinal transit in mice and the intestinal fluid accumulation were used in this study. At the doses of 62.5, 125 and 250 mg/kg p.o., the AALE showed significant antidiarrhoeal activity in both models. The AALE significantly reduced the intestinal fluid accumulation in the castor oil induced enteropooling. AALE delays small intestinal transit possibly, at least in part, involving opioid and α2-adrenergic receptors. The phytochemical analysis revealed the presence of carbohydrates, flavonoids, tannins, saponins and anthraquinones. The results suggest that AALE showed antidiarrhoeal activity by inhibiting intestinal motility and enteropooling property, justify its use in traditional medicine.