New pharmacologic therapies in gastrointestinal disease

Campomanesia lineatifolia Ruiz & Pavón (Myrtaceae): Isolation of major and minor compounds of phenolic-rich extract by high-speed countercurrent chromatography and anti-inflammatory evaluation

ETHNOPHARMACOLOGICAL RELEVANCE

Campomanesia lineatifolia Ruiz & Pavón (Myrtaceae), an edible species found in Brazilian Forest, possesses leaves that are traditionally used for the treatment of gastrointestinal disorders in Brazil. Extracts of C. lineatifolia are rich in phenolics and exhibit antioxidant, and gastric antiulcer properties. Furthermore, Campomanesia spp. have been described to possess anti-inflammatory properties, but studies related to chemical constituents of C. lineatifolia are scarce in the literature.

AIM OF THE STUDY

This work aims to identify the chemical composition of the phenolic-rich ethanol extract (PEE) from C. lineatifolia leaves and evaluate the anti-inflammatory activity that could be related to its ethnopharmacological use.

MATERIALS AND METHODS

The high-speed countercurrent chromatography (HSCCC), using an isocratic and a step gradient elution method, and NMR, HPLC-ESI-QTOF-MS/MS were used to isolate and identify the chemicals of PEE, respectively. Lipopolysaccharide-(LPS)-stimulated THP-1 cells were used to evaluate the anti-inflammatory activities from PEE and the two majority flavonoids isolated by measure TNF-α and NF-κB inhibition assays.

RESULTS

Fourteen compounds were isolated from the PEE, further identified by NMR and HPLC-ESI-QTOF-MS/MS, twelve of them are new compounds, and two others are already known for the species. The PEE, quercitrin and myricitrin promoted a concentration-dependent inhibition of TNF-α, and PEE promoted an inhibition of NF-κB pathway.

CONCLUSIONS

PEE from C. lineatifolia leaves demonstrated significant anti-inflammatory activity that may be related to the traditional use to treat gastrointestinal disorders.

Comparison of Pharmacodynamics between Tegoprazan and Dexlansoprazole Regarding Nocturnal Acid Breakthrough: A Randomized Crossover Study

Background/Aims

Tegoprazan, a novel potassium-competitive acid blocker, is expected to overcome the limitations of proton pump inhibitors and effectively control nocturnal acid breakthrough. To evaluate the pharmacodynamics of tegoprazan versus dexlansoprazole regarding nocturnal acid breakthrough in healthy subjects.

Methods

In a randomized, open-label, single-dose, balanced incomplete block crossover study, 24 healthy male volunteers were enrolled and randomized to receive oral tegoprazan (50, 100, or 200 mg) or dexlansoprazole (60 mg) during each of two administration periods, separated by a 7- to 10-day washout period. Blood samples were collected for pharmacokinetic parameter analysis; gastric monitoring was performed for pharmacodynamic parameter evaluation.

Results

All 24 subjects completed the study. Average maximum plasma concentration, area under the plasma concentration-time curve, and mean time with gastric pH >4 and pH >6 for tegoprazan demonstrated dose-dependent incremental increases. All the tegoprazan groups reached mean pH ≥4 within 2 hours, whereas the dexlansoprazole group required 7 hours after drug administration. Based on pharmacodynamic parameters up to 12 hours after evening dosing, 50, 100, and 200 mg of tegoprazan presented a stronger acid-suppressive effect than 60 mg of dexlansoprazole. Moreover, the dexlansoprazole group presented a comparable acid-suppressive effect with the tegoprazan groups 12 hours after dosing.

Conclusions

All the tegoprazan groups demonstrated a significantly faster onset of gastric pH increase and longer holding times above pH >4 and pH >6 up to 12 hours after evening dosing than the dexlansoprazole group.

Chemical and Pharmacological Potential of Coccoloba cowellii, an Endemic Endangered Plant from Cuba

Coccoloba cowellii Britton (Polygonaceae) is an endemic and critically endangered plant that only grows in Camagüey, a province of Cuba. In this study, a total of 13 compounds were identified in a methanolic leaf extract, employing a dereplication of the UHPLC-HRMS data by means of feature-based molecular networking (FBMN) analysis in the Global Natural Products Social Molecular Network (GNPS), together with the interpretation of the MS/MS data and comparison with the literature. The major constituents were glucuronides and glycosides of myricetin and quercetin, as well as epichatechin-3-O-gallate, catechin, epicatechin and gallic acid, all of them being reported for the first time in C. cowellii leaves. The leaf extract was also tested against various microorganisms, and it showed a strong antifungal effect against Candida albicans ATCC B59630 (azole-resistant) (IC50 2.1 µg/mL) and Cryptococcus neoformans ATCC B66663 (IC50 4.1 µg/mL) with no cytotoxicity (CC50 > 64.0 µg/mL) on MRC-5 SV2 cells, determined by the resazurin assay. Additionally, the extract strongly inhibited COX-1 and COX-2 enzyme activity using a cell-free experiment in a dose-dependent manner, being significantly more active on COX-1 (IC50 4.9 µg/mL) than on COX-2 (IC50 10.4 µg/mL). The constituents identified as well as the pharmacological activities measured highlight the potential of C. cowellii leaves, increasing the interest in the implementation of conservation strategies for this species.

Chemical Constituents, Antioxidant, Cyclooxygenase Inhibitor, and Cytotoxic Activities of Teucrium pruinosum Boiss. Essential Oil

Introduction

In traditional medicine, many pharmacological activities have already been ascribed to the genus of Teucrium plant. These include antirheumatic antispasmodic, anthelmintic, diuretic, hypoglycemic, and anticancer effects. The recent investigation aimed to characterize and estimate the chemical composition, anti-inflammatory, antioxidant, and anticancer potentials of the essential oil isolated by the microwave-ultrasonic apparatus from Teucrium pruinosum leaves collected from Palestine.

Methods

The essential oil (EO) was analyzed by Gas Chromatography equipped with mass spectrometry (GC-MS), while its anticancer activity was evaluated against HeLa cervical adenocarcinoma cells. The ability of T. pruinosum EO to inhibit the conversion of Arachidonic Acid (AA) to PGH₂ by ovine COX-1 and human recombinant COX-2 was determined using a COX inhibitor screening assay. In addition, the antioxidant activity of the EO was evaluated on the basis of the scavenging activity with a stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, while Trolox was used as a positive control.

Results

Forty-four molecules were identified in T. pruinosum EO, representing 100% of the total EO. Agarospirol was found to be the most abundant component (45.53%) followed by caryophyllene (19.35%). However, the cyclooxygenase inhibitor assay revealed that T. pruinosum has potential COX-1 and Cox-2 inhibitory activity with IC₅₀ values of 0.25 µg/ml and 0.5 µg/ml, respectively. Moreover, the T. pruinosum EO showed moderate antioxidant capacity with an IC₅₀ value of 16.98±0.84 µg/ml in comparison with the positive control Trolox, which has an antioxidant potential with an IC₅₀ value of 2.09±0.17 µg/ml. In addition, 250, 125, 62.5, 31.25, 15.625, 7.67, and 3.84 mg/ml of T. pruinosum EO treatments inhibited mitochondrial activity (cell viability) significantly and extremely by 90-95%.

Conclusion

The current study provided data that revealed that the T. pruinosum EO could be a suitable candidate for use as a novel anticancer, anti-inflammatory, and antioxidant medication. Further clinical trials would be required to ensure these effects and to allow the design of suitable pharmaceutical dosage forms from this natural oil.

Evaluation of anti-inflammatory activity of selected medicinal plants used in Indian traditional medication system in vitro as well as in vivo

The present study was carried out to evaluate in vivo and in vitro anti-inflammatory potential of selected medicinal plants used in Indian traditional medication. The sequentially extracted plant samples as, Cissus quadrangularis, Plumbago zeylanica, Terminalia bellarica and Terminalia chebula in water, ethanol and hexane were evaluated in-vitro for COX-1 and 2 inhibitory and antioxidant activities. The in vivo anti-inflammatory activity of selected samples showing promising COX-2 inhibition was assessed using carrageenan and Phorbol Myristate Acetate (PMA) induced mice edema animal model. The results obtained reveals that most of the plants were found to inhibit COX-2 activity as compared to COX-1. It was observed that the extracts of T. bellarica (73.34 %) and T. chebula (74.81 %) showed significant COX-2 selective inhibition as compared to other samples. The ethanol extract of the selected plants demonstrated effective DPPH, OH and superoxide radical scavenging activity. In vivo anti-inflammatory study shows that, T. bellarica and T. chebulla had a significant impact on inhibition of edema formation. The cytotoxicity evaluation study of ethanolic fraction of selected medicinal plants indicates that the selected samples have no effect on cell viability. HPTLC fingerprint of flavonoids of the selected samples was also prepared as a measure of quality control. The results obtained may be useful in strengthening the standardization of the selected botanicals. Moreover the selected plants can be considered as a resource for searching novel anti-inflammatory agents possessing COX-2 inhibition.

The Preventive Effect on Ethanol-Induced Gastric Lesions of the Medicinal Plant Plumeria rubra: Involvement of the Latex Proteins in the NO/cGMP/K ATP Signaling Pathway

Plumeria rubra (Apocynaceae) is frequently used in folk medicine for the treatment of gastrointestinal disorders, hepatitis, and tracheitis, among other infirmities. The aim of this study was to investigate the gastroprotective potential of a protein fraction isolated from the latex of Plumeria rubra (PrLP) against ethanol-induced gastric lesions and describe the underlying mechanisms. In a dose-dependent manner, the pretreatment with PrLP prevented ethanol-induced gastric lesions in mice after single intravenous administration. The gastroprotective mechanism of PrLP was associated with the involvement of prostaglandins and balance of oxidant/antioxidant factors. Secondarily, the NO/cGMP/K_ATP pathway and activation of capsaicin-sensitive primary afferents were also demonstrated as part of the mechanism. This study shows that proteins extracted from the latex of P. rubra prevent gastric lesions induced in experimental animals. Also, the results support the use of the plant in folk medicine.

Recent Advances in NSAIDs-Induced Enteropathy Therapeutics: New Options, New Challenges

The injurious effects of NSAIDs on the small intestine were not fully appreciated until the widespread use of capsule endoscopy. It is estimated that over two-thirds of regular NSAID users develop injury in the small intestinal injuries and that these injuries are more common than gastroduodenal mucosal injuries. Recently, chronic low-dose aspirin consumption was found to be associated with injury to the lower gut and to be a significant contributing factor in small bowel ulceration, hemorrhage, and strictures. The ability of aspirin and NSAIDs to inhibit the activities of cyclooxygenase (COX) contributes to the cytotoxicity of these drugs in the gastrointestinal tract. However, many studies found that, in the small intestine, COX-independent mechanisms are the main contributors to NSAID cytotoxicity. Bile and Gram-negative bacteria are important factors in the pathogenesis of NSAID enteropathy. Here, we focus on a promising strategy to prevent NSAID-induced small intestine injury. Selective COX-2 inhibitors, prostaglandin derivatives, mucoprotective drugs, phosphatidylcholine-NSAIDs, and probiotics have potential protective effects on NSAID enteropathy.

Mechanisms, prevention and clinical implications of nonsteroidal anti-inflammatory drug-enteropathy

This article reviews the latest developments in understanding the pathogenesis, detection and treatment of small intestinal damage and bleeding caused by nonsteroidal anti-inflammatory drugs (NSAIDs). With improvements in the detection of NSAID-induced damage in the small intestine, it is now clear that this injury and the associated bleeding occurs more frequently than that occurring in the stomach and duodenum, and can also be regarded as more dangerous. However, there are no proven-effective therapies for NSAID-enteropathy, and detection remains a challenge, particularly because of the poor correlation between tissue injury and symptoms. Moreover, recent studies suggest that commonly used drugs for protecting the upper gastrointestinal tract (i.e., proton pump inhibitors) can significantly worsen NSAID-induced damage in the small intestine. The pathogenesis of NSAID-enteropathy is complex, but studies in animal models are shedding light on the key factors that contribute to ulceration and bleeding, and are providing clues to the development of effective therapies and prevention strategies. Novel NSAIDs that do not cause small intestinal damage in animal models offer hope for a solution to this serious adverse effect of one of the most widely used classes of drugs.

Advent of novel phosphatidylcholine-associated nonsteroidal anti-inflammatory drugs with improved gastrointestinal safety

The mucosa of the gastrointestinal (GI) tract exhibits hydrophobic, nonwettable properties that protect the underlying epithelium from gastric acid and other luminal toxins. These biophysical characteristics appear to be attributable to the presence of an extracellular lining of surfactant-like phospholipids on the luminal aspects of the mucus gel layer. Phosphatidylcholine (PC) represents the most abundant and surface-active form of gastric phospholipids. PC protected experimental rats from a number of ulcerogenic agents and/or conditions including nonsteroidal anti-inflammatory drugs (NSAIDs), which are chemically associated with PC. Moreover, preassociating a number of the NSAIDs with exogenous PC prevented a decrease in the hydrophobic characteristics of the mucus gel layer and protected rats against the injurious GI side effects of NSAIDs while enhancing and/or maintaining their therapeutic activity. Bile plays an important role in the ability of NSAIDs to induce small intestinal injury. NSAIDs are rapidly absorbed from the GI tract and, in many cases, undergo enterohepatic circulation. Thus, NSAIDs with extensive enterohepatic cycling are more toxic to the GI tract and are capable of attenuating the surface hydrophobic properties of the mucosa of the lower GI tract. Biliary PC plays an essential role in the detoxification of bile salt micelles. NSAIDs that are secreted into the bile injure the intestinal mucosa via their ability to chemically associate with PC, which forms toxic mixed micelles and limits the concentration of biliary PC available to interact with and detoxify bile salts. We have worked to develop a family of PC-associated NSAIDs that appear to have improved GI safety profiles with equivalent or better therapeutic efficacy in both rodent model systems and pilot clinical trials.

Design, synthesis and in vivo anti-inflammatory activities of 2,4-diaryl-5-4H-imidazolone derivatives

A series of 2,4-diaryl-5(4H)-imidazolones were prepared and evaluated for their anti-inflammatory activities. Some selected 2,4-diaryl-5(4H)-imidazolones exhibited excellent anti-inflammatory activity in the carrageenan-induced rat paw edema model. Structure Activity Relationships within the series were studied. The substitution at the N-sulfonamide moiety by a small hydrophilic acetyl group resulted in compounds with superior in vivo anti-inflammatory properties. As expected from their COX-2 selectivity, most of the active compounds lacked gastrointestinal toxicity in vivo in rats after a 3-day treatment of 25 mg/kg/day.

Mangiferin, a natural xanthone, accelerates gastrointestinal transit in mice involving cholinergic mechanism

AIM: To investigate the effects of mangiferin on gastrointestinal transit (GIT) in normal and constipated mice, together with the possible mechanism.

METHODS: Intragastrically-administered charcoal meal was used to measure GIT in overnight starved Swiss mice. In the first experiments, mangiferin (3 mg/kg, 10 mg/kg, 30 mg/kg, and 100 mg/kg, po) or tegaserod (1 mg/kg, ip) were administered 30 min before the charcoal meal to study their effects on normal transit. In the second series, mangiferin (30 mg/kg) was tested on delayed GIT induced by several different pharmacological agonists (morphine, clonidine, capsaicin) or antagonists (ondansetron, verapamil, and atropine) whereas in the third series, mangiferin (30 mg/kg, 100 mg/kg and 300 mg/kg) or tegaserod (1 mg/kg) were tested on 6 h fecal pellets outputted by freely fed mice. The ratio of wet to dry weight was calculated and used as a marker of fecal water content.

RESULTS: Mangiferin administered orally significantly (P < 0.05) accelerated GIT at 30 mg/kg and 100 mg/kg (89% and 93%, respectively), similarly to 5-hydroxytryptamine₄ (5-HT₄) agonist tegaserod (81%) when compared to vehicle-treated control (63%). Co-administered mangiferin (30 mg/kg) totally reversed the inhibitory effect of opioid agonist morphine, 5-HT₃-receptor antagonist ondansetron and transient receptor potential vanilloid-1 receptor agonist capsaicin on GIT, but only to a partial extent with the GIT-delay induced by α₂-adrenoceptor agonist clonidine, and calcium antagonist verapamil. However, co-administered atropine completely blocked the stimulant effect of mangiferin on GIT, suggesting the involvement of muscarinic acetylcholine receptor activation. Although mangiferin significantly enhanced the 6 h fecal output at higher doses (245.5 ± 10.43 mg vs 161.9 ± 10.82 mg and 227.1 ± 20.11 mg vs 161.9 ± 10.82 mg of vehicle-treated control, at 30 and 100 mg/kg, P < 0.05, respectively), the effect of tegaserod was more potent (297.4 ± 7.42 mg vs 161.9 ± 10.82 mg of vehicle-treated control, P < 0.05). Unlike tegaserod, which showed an enhanced water content in fecal pellets (59.20% ± 1.09% vs 51.44% ± 1.19% of control, P < 0.05), mangiferin evidenced no such effect, indicating that it has only a motor and not a secretomotor effect.

CONCLUSION: Our data indicate the prokinetic action of mangiferin. It can stimulate the normal GIT and also overcome the drug-induced transit delay, via a cholinergic physiological mechanism.

Non-steroidal anti-inflammatory drug-induced enteropathy

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed drugs in the world. NSAID-induced lower gastrointestinal (GI) complications are increasing while upper GI complications are decreasing. Lower GI events accounted for 40% of all serious GI events in patients on NSAIDs. Capsule endoscopy and device assisted enteroscopy are available for detection of small intestinal lesions. Capsule endoscopy studies have demonstrated that NSAIDs use in healthy volunteers raised the incidence (55% to 75%) of intestinal damage. It appears that selective cyclooxygenase-2 inhibitors (coxibs) improved upper and lower GI safety based on results of clinical trials. Selective coxibs are still capable of triggering GI adverse events and cardiovascular toxicity issues were the main focus of concerns. Unfortunately, definite strategies are not available to prevent or heal NSAID-induced intestinal injuries. Thus, there is still a strong clinical need for effective drugs with improved safety profiles than the existing NSAIDs.

NSAID gastropathy and enteropathy: distinct pathogenesis likely necessitates distinct prevention strategies

The mechanisms underlying the ability of nonsteroidal anti-inflammatory drugs (NSAIDs) to cause ulceration in the stomach and proximal duodenum are well understood, and this injury can largely be prevented through suppression of gastric acid secretion (mainly with proton pump inhibitors). In contrast, the pathogenesis of small intestinal injury induced by NSAIDs is less well understood, involving more complex mechanisms than those in the stomach and proximal duodenum. There is clear evidence for important contributions to NSAID enteropathy of enteric bacteria, bile and enterohepatic recirculation of the NSAID. There is no evidence that suppression of gastric acid secretion will reduce the incidence or severity of NSAID enteropathy. Indeed, clinical data suggest little, if any, benefit. Animal studies suggest a significant exacerbation of NSAID enteropathy when proton pump inhibitors are co-administered with the NSAID. This worsening of damage appears to be linked to changes in the number and types of bacteria in the small intestine during proton pump inhibitor therapy. The distinct mechanisms of NSAID-induced injury in the stomach/proximal duodenum versus the more distal small intestine likely dictate distinct strategies for prevention.

Nitric oxide release is not required to decrease the ulcerogenic profile of nonsteroidal anti-inflammatory drugs

The objective of this work was to evaluate the biological properties of a new series of nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) possessing a tyrosol linker between the NSAID and the NO-releasing moiety (PROLI/NO); however, initial screening of ester intermediates without the PROLI/NO group showed the required (desirable) efficacy/safety ratio, which questioned the need for NO in the design. In this regard, NSAID ester intermediates were potent and selective COX-2 inhibitors in vitro, showed equipotent anti-inflammatory activity compared to the corresponding parent NSAID, but showed a markedly reduced gastric toxicity when administered orally. These results provide complementary evidence to challenge the currently accepted notion that hybrid NO-NSAIDs exert their cytoprotective effects by releasing NO. Results obtained in this work constitute a good body of evidence to initiate a debate about the future replacement of NSAID prodrugs for unprotected NSAIDs (possessing a free carboxylic acid group) currently in clinical use.