Irma Romero

Curcumin (CUR) is the primary metabolite isolated from the Curcuma longa L. rhizome. Most synthetic and biological studies have focused mainly on the curcumin molecule due to its essential biological activity as an antioxidant, anti-cancer, and anti-Alzheimer’s disease agent. However, the natural extract of turmeric also contains two essential curcuminoids (demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC)), which altogether comprise the so-called C-3 complex. They are present in commercial compositions for treating biliary or digestive ailments. The vegetal rhizome’s extraction typically leads to a mixture of the three main curcuminoids, CUR, DMC, and BDMC, in variable proportions, and each of these metabolites has reported specific synthetic routes. Herein, we have performed the synthesis and isolation of the three major curcuminoids using the method called scrambling of aldehydes followed by aldol di-condensation reactions. A density functional theory (DFT) approach supported the experimental results by inspecting the predicted energies for the aldol condensation. Thus, the di-condensation reaction is substantially favoured (ΔG° = −2685.9 kJ/mol) over the mono-condensation reaction (ΔG° = −1393.753 kJ/mol). Our approach allows us to mimic closely the proportions of these curcuminoids found in extracts from natural sources that follow the order CUR > DMC > BDMC, respectively. The proportion of aldehydes can be modified in the scrambling reaction with an adequate mixture of aldehydes to render the order DMC > CUR > BDMC. This is an advantageous way to increase the amount of the unsymmetric DMC metabolite.

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.

The objective of this study was to determine the pharmacological interaction of some common NSAIDs in the presence of quercetin (QUER). Indomethacin (IND), ketorolac (KET), or celecoxib (CEL) were assessed alone and in combination with QUER using experimental gout-arthritic pain and the carrageenan-induced edema test in rats to evaluate their antinociceptive and anti-inflammatory effects, respectively. The antinociceptive effect of each NSAID was also analyzed after the repeated administration of QUER for 10 days. Molecular docking analysis on COX-1/COX-2 with each drug was explored to analyze the pharmacological interaction. QUER produced minimal antinociceptive or anti-inflammatory effects on experimental gout-arthritic pain or on the carrageenan-induced edema in rats. Additionally, QUER reduced the antinociceptive effect of NSAIDs, mainly those COX-1 inhibitors (IND and KET), when they were combined. However, QUER did not modify the anti-inflammatory effect of these COX-1 inhibitors and slightly improved the anti-inflammatory effect of the COX-2 inhibitor (CEL). According to the docking analysis, COX-1 and COX-2 are likely implicated in these pharmacological interactions. In conclusion, QUER, a known bioactive natural product, may alter the antinociceptive efficacy of NSAIDs commonly used to relieve gout-like pain and suggests not using them together to prevent a negative therapeutic interaction in this effect.

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.

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.

Helicobacter pylori (H. pylori) is a successful pathogen that can persist in the stomach of an infected person for their entire life. It provokes chronic gastric inflammation that leads to the development of serious gastric diseases such as peptic ulcers, gastric cancer and Mucosa associated lymphoid tissue lymphoma. It is known that these ailments can be avoided if the infection by the bacteria can be prevented or eradicated. Currently, numerous antibiotic-based therapies are available. However, these therapies have several inherent problems, including the appearance of resistance to the antibiotics used and associated adverse effects, the risk of re-infection and the high cost of antibiotic therapy. The delay in developing a vaccine to prevent or eradicate the infection has furthered research into new therapeutic approaches. This review summarises the most relevant recent studies on vaccine development and new treatments using natural resources such as plants, probiotics and nutraceuticals. In addition, novel alternatives based on microorganisms, peptides, polysaccharides, and intragastric violet light irradiation are presented. Alternative therapies have not been effective in eradicating the bacteria but have been shown to maintain low bacterial levels. Nevertheless, some of them are useful in preventing the adverse effects of antibiotics, modulating the immune response, gastroprotection, and the general promotion of health. Therefore, those agents can be used as adjuvants of allopathic anti-H. pylori eradication therapy.