Erika Gomez-Chang

Helicobacter pylori is the main etiological factor of gastritis, peptic ulcers, and gastric cancer. This bacterium’s antibiotic resistance has led to a lower eradication rate; therefore, new drugs with anti-H. pylori activity are needed. Curcumin exhibits multiple biological activities, but it has low stability and poor bioavailability. To overcome these disadvantages, different metal complexes have been synthesized. The objective of this study was to determine the in vitro anti-H. pylori activity of diacetylcurcumin (DAC), DAC₂-Cu, DAC₂-Zn, DAC₂-Mn, and DAC₂-Mg by obtaining the minimum inhibitory concentration of bacterial growth, and to investigate some mechanisms by which they could affect the bacteria (urease and DNA gyrase activities). Moreover, their gastroprotective potential was assayed in an ethanol-induced gastric ulcer model in mice. The results showed that DAC₂-Cu and DAC₂-Zn have good anti-H. pylori activity, exhibit specific activity against this bacterium, inhibit the urease activity, and provide 70% gastroprotection at a dose of 200 mg/kg of body weight. In a subacute toxicity study in mice, DAC₂-Cu and DAC₂-Zn did not cause death or any deleterious symptoms, nor did they have a significant effect on serum and urine biochemical parameters compared to control mice. These compounds are promising candidates for use in H. pylori eradication schemes.

Artemisia ludoviciana subsp. mexicana has been traditionally used for the treatment of digestive ailments such as gastritis, whose main etiological agent is Helicobacter pylori. In a previous screening study, the aqueous extract exhibited a good in vitro anti-H. pylori activity. With the aim of determining the efficacy of this species as a treatment for H. pylori related diseases and finding bioactive compounds, its aqueous extract was subjected to solvent partitioning and the fractions obtained were tested for their in vitro anti-H. pylori effect, as well as for their in vivo gastroprotective and anti-inflammatory activities. The aqueous extract showed a MIC = 250 µg/mL. No acute toxicity was induced in mice. A gastroprotection of 69.8 ± 3.8%, as well as anti-inflammatory effects of 47.6 ± 12.4% and 38.8 ± 10.2% (by oral and topical administration, respectively), were attained. Estafiatin and eupatilin were isolated and exhibited anti-H. pylori activity with MBCs of 15.6 and 31.2 µg/mL, respectively. The finding that A. ludoviciana aqueous extract has significant anti-H. pylori, gastroprotective and anti-inflammatory activities is a relevant contribution to the ethnopharmacological knowledge of this species. This work is the first report about the in vivo gastroprotective activity of A. ludoviciana and the anti-H. pylori activity of eupatilin and estafiatin.

“Quelites” are edible plants that are part of the traditional agro-ecosystems in Mexico. These plants, despite their already known nutritional properties, are now considered neglected and underutilized species. With the objective of promoting their reinsertion in the markets and mainly, in daily diets, efforts have been made to study them from multidisciplinary approaches to demonstrate their beneficial properties. To generate evidence of an added health-promoting value that would encourage quelites consumption, in the present work, the anti- Helicobacter pylori activity of three representative quelite species, Anoda cristata (Alache), Cnidoscolus aconitifolius (Chaya), and Crotalaria pumila (Chepil), was tested. H. pylori is considered the etiological agent of gastritis, ulcer, and gastric cancer, and represents a public health problem in Mexico and worldwide. Aqueous (AQ) and dichloromethane–methanol (DM) extracts were obtained from the three species of quelites to investigate their effect on H. pylori growth and on two of its colonization factors (adherence and urease activity). DM extracts from Chaya, Chepil, and Alache exert the best inhibitory effect on bacterial growth, with minimum inhibitory concentrations of 62.5, 125, and 250 μ g/mL, respectively. AQ and DM extracts inhibit bacterial adhesion by 30% to 50%. None of them has an effect on urease activity. The two flavonoids present in A. cristata , acacetin and diosmetin, inhibit H. pylori growth by ∼90% with 3.9 μ g/mL. These results provide new information about the anti- H. pylori potential of three edible quelites, and give an added value, since their routine consumption may impact on the prevention and/or control of H. pylori- associated diseases.

Gastric ulcers are a worldwide health problem and their poor healing is one of the most important causes for their recurrence. We have previously reported the remarkable gastroprotective and anti‐Helicobacter pylori activities of the methanolic extract (CpMet) of Cyrtocarpa procera bark. This work investigates, in a murine model, the CpMet gastroprotective mechanism and establishes its preclinical efficacy in the resolution of ethanol‐induced gastric ulcers. The results showed that the gastroprotective activity of CpMet is mainly associated with endogenous NO and prostaglandins, followed by sulfhydryl groups and K_ATP channels. Furthermore, CpMet (300 mg/kg, twice a day) orally administered during 20 consecutive days promoted an ulcer area reduction of 62.65% at the 20th day of the treatment. The effect was confirmed macroscopically by the alleviation of gastric mucosal erosions and microscopically by an increase in mucin content and a reduction in the inflammatory infiltration at the site of the ulcer. No clinical symptoms or signs of toxicity were observed in the treated animals. The results indicate the safety and efficacy of CpMet in promoting high quality of ulcer healing by different mechanisms, but mostly through cytoprotective and anti‐inflammatory effects, making it a promising phytodrug for ulcer treatment.