Studies on the possible mechanism of the gastric mucosal protection by Calotropis procera--involvement of 5-lipoxygenase pathway

Antiulcer properties of fruits and vegetables: A mechanism based perspective

Gastric ulcer is the damage caused to mucosal layer of the stomach under the action of various factors like high levels of acid and pepsin, invasion by Helicobacter pylori, etc. Although most cases have been controlled and the rate of ulcer occurrence has reduced over the last few decades, gastric ulcer still holds a prime concern today. A range of palliative medicines comprising proton pump inhibitors, H2 receptor antagonists, COX-2 inhibitors (coxibs) is widely in use and patients have also been administered with acid suppression therapies. But these remedies aggravate the condition of patients causing severe side effects, or rather impart temporary relief. Therefore, it is highly imperative to develop safe and effective therapies for the treatment of gastric ulcer. Nature provides us various fruits and vegetables that can combat gastric ulcer through multiple mechanisms; predominantly via antioxidant, anti-inflammatory, antisecretory, antimicrobial, anticholinergic and cytoprotective activity, inhibition of small intestinal propulsion etc. Various phytochemicals from fruits and vegetables such as phenolics, flavonoids, tannins and saponins play a vital role in the prevention and cure of gastric ulcer. This review is a compendium of all fruits and vegetables known for their profound antiulcer effect and their underlying mechanisms of action.

Medicinal plants, human health and biodiversity: a broad review

Biodiversity contributes significantly towards human livelihood and development and thus plays a predominant role in the well being of the global population. According to WHO reports, around 80 % of the global population still relies on botanical drugs; today several medicines owe their origin to medicinal plants. Natural substances have long served as sources of therapeutic drugs, where drugs including digitalis (from foxglove), ergotamine (from contaminated rye), quinine (from cinchona), and salicylates (willow bark) can be cited as some classical examples.Drug discovery from natural sources involve a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Accordingly, medicinal-plant-based drug discovery still remains an important area, hitherto unexplored, where a systematic search may definitely provide important leads against various pharmacological targets.Ironically, the potential benefits of plant-based medicines have led to unscientific exploitation of the natural resources, a phenomenon that is being observed globally. This decline in biodiversity is largely the result of the rise in the global population, rapid and sometimes unplanned industrialization, indiscriminate deforestation, overexploitation of natural resources, pollution, and finally global climate change.Therefore, it is of utmost importance that plant biodiversity be preserved, to provide future structural diversity and lead compounds for the sustainable development of human civilization at large. This becomes even more important for developing nations, where well-planned bioprospecting coupled with nondestructive commercialization could help in the conservation of biodiversity, ultimately benefiting mankind in the long run.Based on these findings, the present review is an attempt to update our knowledge about the diverse therapeutic application of different plant products against various pharmacological targets including cancer, human brain, cardiovascular function, microbial infection, inflammation, pain, and many more.

Protective effect of Calotropis procera latex extracts on experimentally induced gastric ulcers in rat

AIM OF THE STUDY

Calotropis procera is a wild growing plant with multifarious medicinal properties. The present study was carried out to evaluate the effect of dried latex (DL) of Calotropis procera and its methanol extract (MeDL) against gastric ulcers induced in rats.

MATERIALS AND METHODS

Aqueous suspension of DL (20 and 100mg/kg) and MeDL (10 and 50mg/kg) were given orally to 36h fasted rats and ulcers were induced by ethanol, pyloric ligation and aspirin. Parameters like ulcer score and levels of oxidative stress markers were measured in all the models. The effect on gastric hemorrhage and tissue histology was studied in ethanol model and on acidity, pH and volume of gastric secretion was evaluated in pyloric ligation model. The protective effect of DL and MeDL was compared with that of standard anti-ulcer drug famotidine (20 mg/kg).

RESULTS

DL and MeDL produced 85-95% inhibition of gastric mucosal damage in ethanol model and 70-80% inhibition in aspirin model. The protective effect of these extracts was associated with marked reduction in gastric hemorrhage, maintenance of tissue integrity and normalization of levels of oxidative stress markers like glutathione, thiobarbituric acid reactive substances and superoxide dismutase. Like famotidine, DL and MeDL decreased the gastric acidity from 376.17+/-21.47 mequiv./l to 163.88+/-6.86 and 201.48+/-8.86 mequiv./l respectively in pyloric ligation model. These extracts increased the gastric pH without affording any protection to gastric mucosa in this model.

CONCLUSION

The latex of Calotropis procera has the therapeutic potential to relieve gastric hyperacidity and to prevent gastric ulceration induced by necrotizing agents.

Anti-inflammatory activity of Acanthus ilicifolius

Acanthus ilicifolius Linn, is a perennial herb (Acanthaceae) widely found in the Sundarban mangroves and is popularly used for its wound healing effects. In the present study an attempt was made to evaluate the anti-inflammatory activity of the Acanthus ilicifolius leaves. The methanolic fraction of Acanthus ilicifolius leaf extract produced significant inhibition of rat paw oedema, when administered both prior to and after carrageenan administration, in a manner similar to BW755C a synthetic cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor. The extract decreased protein exudation and leukocyte migration in the peritoneal fluid, thereby indicating its effectiveness towards inhibiting peritoneal inflammation. It also produced significant inhibition of COX (1 and 2) and 5-LOX activity. Preincubation of the extract inhibited the production of proinflammatory cytokines (TNFalpha and IL-6) in lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs). The methanolic fraction of the extract was also found to possess significant free radical (DPPH, ABTS, superoxide and hydroxyl radical) scavenging activity. The extract on intraperitoneal administration augmented the endogenous antioxidant status, as evident from the significant increase of ferric reducing ability of plasma (FRAP) and total peroxyl radical trapping activity of plasma (TRAP).