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Abstract

Phytochemical study on Harpullia pendula pericarp resulted in isolation of the five gallotannins 1,2,3,4,6-penta-O-galloyl-ß-D-4Cr glucopyranoside (1), 1,2,3,6-tetra-O-galloyl-ß-D-4Crglucopyranoside (2), 1,3,6-tri-O-galloyl-ß-D-4C1-glucopyranoside (3), gallic acid (4), and methyl gallate (5) for the first time from the genus. Structures were established based on physical and spectroscopic data. The gastroprotective activity of pentagalloyl glucose (1) was evaluated in aspirin induced ulcer in rats, as compared to omeprazole, famotidine and melatonin. For assessment, pH of the gastric stomach juice as well as the ulcer number and severity were determined. In addition, the levels of prostaglandin, cyclooxygenase (COX-2), tumor necrosis factor-alpha (TNF-a), interleukin-1 (IL-1), glutathione (GSH) and malondialdehyde (MDA) were determined in gastric tissue homogenate. Results showed that pentagalloyl glucose induces increment of gastric juice pH, with decrement in number and severity of gastric mucosal ulcers and decreases the level of TNF-a and IL-1, as compared to the aspirin group. In addition, pentagalloyl glucose (100 and 200 mg/kg), famotidine and omeprazole normalized the elevated level of glutathione with decrease of malondialdehyde level, as compared to aspirin group. Furthermore, rats treated with either pentagalloyl glucose, famotidine, omeprazole or melatonin showed significant increase in prostaglandin level and significant decrease in gastric COX-2 level, as compared to aspirin group. Obtained results were supported by histopathological study.

Keywords

Antioxidant; aspirin; gastric mucosal damage; inflammatory cytokine; pentagalloyl glucose

Introduction

Peptic ulcer represents one of the most common disorders of the gastrointestinal tract, affecting about 5-10% of the people during their lives [1]. In addition, it is considered as one of the most important causes of morbidity and mortality during the 20th and 21st centuries [2]. Ulcers are responsible for upper gastrointestinal bleeding and major clinical problem resulting from the wide use of nonsteroidal anti-inflammatory drugs as aspirin, which is considered as one of the ulcer inducers [2,3]. Aspirin is a medication widely used for pain and inflammation treatment, in addition to its use in cardiovascular diseases due to its antiplatelet properties. The most common ulcers associated with peptic ulcer disease arise in the stomach and duodenum but the gastric ulcers are most frequently [4]. Gastric acid, cytokines, interleukin-1, tumor necrosis factor [5] represent major factors that play an important role in inducing mucosal damage [6,7]. Even the use of suitable gastrointestinal therapy may delay ulcers in...

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