Spices, herbal xenobiotics and the stomach: friends or foes?

Spices and herbal remedies have been used since ancient times to treat a variety of disorders. It has been experimentally demonstrated that spices, herbs, and their extracts possess antimicrobial, anti-inflammatory, antirheumatic, lipid-lowering, hepatoprotective, nephroprotective, antimutagenic and anticancer activities, besides their gastroprotective and anti-ulcer activities. Despite a number of reports on the toxicity of herbs and spices, they are generally accepted as safer alternatives to conventional therapy against gastric ulcers. To this end, it is also believed, that excessive consumption of spices may favor the pathogenesis of gastric and duodenal ulcer and some studies have substantiated this common perception. Based on various in vivo experiments and clinical studies, on the effects of spices and herbs on gastric ulcers, it has indeed been shown that certain spices do possess remarkable anti-ulcer properties mediated by antisecretory, cytoprotective, antioxidant, and anti-Helicobacter pylori effects and mechanisms regulated by nitric oxide, prostaglandins, non-protein sulfhydryl molecules and epidermal growth factor expression. Accordingly, their consumption may attenuate and help prevent peptic ulcer disease. In the present review, the beneficial effects of spices and herbal nutritive components on the gastric mucosa are discussed against the paradigm of their deleterious potential.