title: Mechanism(s) of action involved in the gastroprotective activity of Muntingia calabura.
abstract: BACKGROUND
  Muntingia calabura L. (Muntingiaceae) is locally known as kerukup siam. Its leaves, flowers, barks and roots have been used traditionally in East Asia and South America to treat various diseases including ulcer-related diseases. The present study aimed to investigate the mechanism(s) of gastroprotective effect of methanol extract of Muntingia calabura leaves (MEMC) using the pylorus ligation induced gastric ulceration in rats.
  
  
  METHODS
  Five groups of rats (n=6) were administered orally once daily for 7 days with 8% Tween 80 (negative control), 100 mg/kg ranitidine (positive control), or MEMC (100, 250 or 500 mg/kg), followed by the ulcer induction via ligation of the pyloric part of the rat's stomach. This was followed by the macroscopic analysis of the stomach, evaluation of gastric content parameters, and quantification of mucus content. The antioxidant (measured using the superoxide anion and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging, oxygen radical absorbance capacity (ORAC) and total phenolic content (TPC) assays), anti-inflammatory (evaluated using the in vitro lipoxygenase and xanthine oxidase assays), phytoconstituents and HPLC analysis of MEMC were also carried out.
  
  
  RESULTS
  The MEMC significantly (p<0.05) reduced gastric lesion in this model. Furthermore, the extract also significantly (p<0.01) reduced the volume of gastric content whereas the total acidity was significantly (p<0.05) reduced in the doses of 100 and 500 mg/kg MEMC. Moreover, the mucus content increased significantly (p<0.01) in MEMC-treated rats. The extract also showed high antioxidant and anti-inflammatory activities in all assays tested, and demonstrated the presence of high tannins and saponins followed by flavonoids.
  
  
  CONCLUSIONS
  The MEMC exerted gastroprotective effect via several mechanisms including the anti-secretory, antioxidant and anti-inflammatory activities. These activities could be attributed to the presence of tannins, saponins and flavonoids (e.g. rutin, quercitrin, fisetin and dihydroquercetin).
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia. Electronic address: dr_zaz@yahoo.com.
authors.forename: Zainul Amiruddin
authors.initials: ZA
authors.lastname: Zakaria
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
authors.forename: Tavamani
authors.initials: T
authors.lastname: Balan
authors.affiliation: Department of Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
authors.forename: Velan
authors.initials: V
authors.lastname: Suppaiah
authors.affiliation: Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
authors.forename: Syahida
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: Natural Products Division, Forest Research Institute Malaysia (FRIM), 52109 Kepong, Selangor, Malaysia.
authors.forename: Fadzureena
authors.initials: F
authors.lastname: Jamaludin
mesh_terms: D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D005750:Gastric Juice / Q000378:metabolism; D008084:Lipoxygenase / Q000378:metabolism; D008297:Male; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D064209:Phytochemicals / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013276:Stomach Ulcer / Q000188:drug therapy / Q000378:metabolism*; D064028:Tracheophyta; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000897:Anti-Ulcer Agents; D000975:Antioxidants; D064209:Phytochemicals; D010936:Plant Extracts; D009569:Nitric Oxide; D008084:Lipoxygenase; D014969:Xanthine Oxidase
keywords: Anti-inflammation; Anti-secretory; Antioxidant; Gastric ulcer; Muntingia calabura; Muntingiaceae