Gastroprotective Effect of an Aqueous Suspension of Black Cumin Nigella sativa on Necrotizing Agents-Induced Gastric Injury in Experimental Animals

Gastric ulcers, one of the most widespread diseases, is believed to be due to an imbalance between aggressive and protective factors.[1] The gastric mucosa is continuously exposed to potentially injurious agents such as acid, pepsin, bile acids, food ingredients, bacterial products (Helicobacter pylori) and drugs.[2] These agents have been implicated in the pathogenesis of gastric ulcer, including enhanced gastric acid and pepsin secretion, inhibition of protaglandin synthesis and cell proliferation growth, diminished gastric blood flow and gastric motility.[3] Drug treatment of peptic ulcers is targeted at either counteracting aggressive factors (acid, pepsin, active oxidants, platelet aggravating factor “PAF,” leukotrienes, endothelins, bile or exogenous factors including NSAIDs) or stimulating the mucosal defenses (mucus, bicarbonate, normal blood flow, prostaglandins (PG), nitric oxide).[4] The goals of treating peptic ulcer disease are to relieve pain, heal the ulcer and prevent ulcer recurrence. Currently, there is no cost-effective treatment that meets all these goals. Hence, efforts are on to find a suitable treatment from natural product sources. A large percentage of world population relies on natural remedies to treat a variety of diseases. Due to socio-economic factors, faith and ancestral experience, medicinal herbs and spices are considered as an indispensable part of traditional medicine.[5] Besides this, a large number of spices and herbs have been evaluated by various researchers for their anti-ulcer effects to achieve a favorable outcome.[6–12] The seeds of Nigella sativa L. (Rananculacene) (NS) known as Black seed or Black cumin (“Al Habbah Al Sawda” or “Habbatul-Barakah”) have long been used in folk medicine in the Middle East, Far East and in the Indian subcontinent as a traditional medicine. The Ayurvedic, Unani and herbal medicine practitioners extensively used this age old spice for a wide range of illnesses, including bronchial asthma, headache, dysentery, infections, obesity, back pain, hypertension and gastrointestinal problems as well as a diuretic, and to promote menstruation and increase lactation.[13–15] Its use in skin conditions as eczema has also been recognized worldwide.[16] NS contains more than 30% of a fixed oil and 0.40-0.45 w/w of a volatile oil. The volatile oil has been shown to contain 18-24% thymoquinone (TQ) and 46% monoterpenes.[16] Recent clinical and experimental studies have shown several therapeutic effects of NS extracts including its antioxidant hepatoprotective,[17] immunomodulatory,[18] anti-inflammatory[19] and anti-tumor[20] activities. However, recently the active principle of NS oil TQ has shown to possess a gastroprotective activity in rats.[16] In other studies, TQ has demonstrated an antimicrobial activity[21] and was beneficial for treating doxorubicin-induced nephropathy in rats.[22] Although much work has been done on crude extract of NS and its constituents, to our knowledge, there is no report available on its aqueous suspension dosage form. NS seeds are customarily consumed either in their intact or powdered forms. Therefore, the present study was undertaken to determine the effect of an aqueous suspension of NS seeds against various necrotizing agents and indomethacin-induced gastric ulcer in rats. Anti-secretory assessment was performed on pylorus-ligated Shay rats. Gastric wall mucus and non-protein sulfhydryl contents were estimated and gastric tissue was histopathologically examined.