Gastroprotective capability of exogenous phosphatidylcholine in experimentally induced chronic gastric ulcers in rats

The Potential for Phospholipids in the Treatment of Airway Inflammation: An Unexplored Solution

Asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) are major inflammatory respiratory diseases. Current mainstay therapy for asthma, and chronic obstructive pulmonary disease are corticosteroids, which have well-established side effect profiles. Phospholipids (PLs) are ubiquitous, diverse compounds with varying functions such as their structural role incell membrane, energy storage, and cell signaling.Recent advances in understanding PLs role as inflammatory mediators in the body as well as their widespread long-standing use as carrier molecules in drug delivery demonstrate the potential application of phospholipids in modulating inflammatory conditions. This review briefly explains the main mechanisms of inflammation in chronic respiratory diseases, currentanti-inflammatory treatments and areas of unmet need. The structural features, roles of endogenous and exogenous phospholipids, including their use as pharmaceutical excipients are reviewed. Current research on the immunomodulatory properties of PLs and their potentialapplication in inflammatory diseasesis the major section of this review. Considering the roles of PLs as inflammatory mediators and their safety profile established in pharmaceutical formulations, these small molecules demonstrate great potential as candidates in respiratory inflammation. Future studies need to focus on the immunomodulatory properties and the underlying mechanisms of phospholipids in respiratory inflammatory diseases.

Role of dietary phospholipids and phytosterols in protection against peptic ulceration as shown by experiments on rats

Geographically the prevalence of duodenal ulceration is related to the staple foods in the diet in regions of developing countries where the diet is stable. It is higher in regions where the diet is based on milled rice, refined wheat or maize, yams, cassava, sweet potato, or green bananas, and is lower in regions where the staple diet is based on unrefined wheat or maize, soya, certain millets or certain pulses. Experiments on rat gastric and duodenal ulcer models showed that it was the lipid fraction in staple foods from low prevalence areas that was protective against both gastric and duodenal ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs). It also promoted ulcer healing. The lipid from the pulse, Dolichos biflorus, horse gram which was highly protective was used to identify the fractions with protective activity in the lipid. The protective activity lay in the phospholipid, sterol and sterol ester fractions. In the phospholipid fraction phosphatidyl choline (lethicin) and phosphatidyl ethanolamine (cephalin) were predominant. In the sterol fraction the sub-fractions showing protective activity contained β-sitosterol, stigmasterol, and an unidentified isomer of β-sitosterol. The evidence from animal models shows that certain dietary phospholipids and phytosterols have a protective action against gastroduodenal ulceration, both singly and in combination. This supports the protective role of staple diets in areas of low duodenal ulcer prevalence and may prove to be of importance in the prevention and treatment of duodenal ulceration and management of recurrent ulcers. A combination of phospholipids and phytosterols could also play an important role in protection against ulceration due to NSAIDs.

Orally administered phosphatidic acids and lysophosphatidic acids ameliorate aspirin-induced stomach mucosal injury in mice

BACKGROUND

Recent investigations revealed that lysophosphatidic acid (LPA), a phospholipid with a growth factor-like activity, plays an important role in the integrity of the gastrointestinal tract epithelium.

AIM

This paper attempts to clarify the effect of orally administered phosphatidic acid (PA) and LPA on aspirin-induced gastric lesions in mice.

MATERIALS AND METHODS

Phospholipids, a free fatty acid, a diacylglycerol and a triglyceride at 1 mM (5.7 μmol/kg body weight) or 0.1 mM were orally administered to mice 0.5 h before oral administration of aspirin (1.7 mmol/kg). The total length of lesions formed on the stomach wall was measured as a lesion index. Formation of LPA from PA in the mouse stomach was examined by in vitro (in stomach lavage fluid), ex vivo (in an isolated stomach) and in vivo (in the stomach of a living mouse) examinations of phospholipase activity.

RESULTS

Palmitic acid, dioleoyl-glycerol, olive oil and lysophosphatidylcholine did not affect the aspirin-induced lesions. In contrast, phosphatidylcholine (1 mM), LPA (1 mM) and PA (0.1, 1 mM) significantly reduced the lesion index. Evidence for formation of LPA from PA in the stomach by gastric phospholipase A2 was obtained by in vitro, ex vivo and in vivo experiments. An LPA-specific receptor, LPA2, was found to be localized on the gastric surface-lining cells of mice.

CONCLUSION

Pretreatment with PA-rich diets may prevent nonsteroidal anti-inflammatory drug-induced stomach ulcers.

Intragastrically administered lysophosphatidic acids protect against gastric ulcer in rats under water-immersion restraint stress

BACKGROUND AND AIM

Lysophosphatidic acid exerts important physiological effects on many types of animal cells through its specific binding to several G protein-coupled receptors. In particular, its potent wound-healing effect has attracted much attention. To determine whether lysophosphatidic acids in a foodstuff and Chinese medicine are effective in protecting against gastric ulcer, we subjected rats to water-immersion restraint stress.

METHODS AND RESULTS

Three direct administrations of a solution of lysophosphatidic acid with a C18 fatty acyl group to the rat stomach in a concentration range of 0.001-0.1 mM resulted in a significant reduction in the number of gastric ulcers induced during water-immersion restraint stress, and the potencies were as follows: linoleoyl species=α-linolenoyl species>oleoyl species. Intragastric administrations of a solution of highly purified lysophosphatidic acid from soybean lecithin significantly protected against the stress-induced gastric ulcers at lower concentrations than partially purified lysophosphatidic acid from soybean lecithin did. In addition, administration of a decocted solution of antyu-san, and lysophosphatidic acid-rich Chinese medicine, to the stomach was more effective in protecting against stress-induced ulcer than decoctations of antyu-san lacking the corydalis tuber component that is rich in lysophosphatidic acid.

CONCLUSIONS

These results clearly show that lysophosphatidic acid is the effective component of soybean lecithin and antyu-san in protection against stress-induced gastric ulcer in the rat model, and suggest that daily intake of lysophosphatidic acid-rich foods or Chinese medicines may be beneficial for prevention of stress-induced gastric ulcer in human subjects.

Dietary Phytosterols Protective Against Peptic Ulceration

BACKGROUND

In developing countries the prevalence of duodenal ulceration is related to the staple diet and not to the prevalence of Helicobacter pylori. Experiments using animal peptic ulcer models show that the lipid fraction in foods from the staple diets of low prevalence areas gives protection against ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs), and also promotes healing of ulceration. The lipid from the pulse Dolichos biflorus (Horse gram) was highly active and used for further investigations. Further experiments showed the phospholipids, sterol esters and sterols present in Horse gram lipid were gastroprotective. Dietary phospholipids are known to be protective, but the nature of protective sterols in staple diets is not known. The present research investigates the nature of the protective phytosterols.

METHODS

Sterol fractions were extracted from the lipid in Dolichos biflorus and tested for gastroprotection using the rat ethanol model. The fractions showing protective activity were isolated and identification of the components was investigated by Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS

The protective phytosterol fraction was shown to consist of stigmasterol, β-sitosterol and a third as yet unidentified sterol, isomeric with β-sitosterol.

CONCLUSIONS

Dietary changes, affecting the intake of protective phospholipids and phytosterols, may reduce the prevalence of duodenal ulceration in areas of high prevalence and may reduce the incidence of recurrent duodenal ulceration after healing and elimination of Helicobacter pylori infection. A combination of phospholipids and phytosterols, such as found in the lipid fraction of ulceroprotecive foods, may be of value in giving protection against the ulcerogenic effect of NSAIDs.

Phospholipids and lipid-based formulations in oral drug delivery

Phospholipids become increasingly important as formulation excipients and as active ingredients per se. The present article summarizes particular features of commonly used phospholipids and their application spectrum within oral drug formulation and elucidates current strategies to improve bioavailability and disposition of orally administered drugs. Advantages of phospholipids formulations not only comprise enhanced bioavailability of drugs with low aqueous solubility or low membrane penetration potential, but also improvement or alteration of uptake and release of drugs, protection of sensitive active agents from degradation in the gastrointestinal tract, reduction of gastrointestinal side effects of non-steroidal anti-inflammatory drugs and even masking of bitter taste of orally applied drugs. Technological strategies to achieve these effects are highly diverse and offer various possibilities of liquid, semi-liquid and solid lipid-based formulations for drug delivery optimization.

TNF-alpha-induced up-regulation of pro-inflammatory cytokines is reduced by phosphatidylcholine in intestinal epithelial cells

Background

Phosphatidylcholine (PC) is a major lipid of the gastrointestinal mucus layer. We recently showed that mucus from patients suffering from ulcerative colitis has low levels of PC. Clinical studies reveal that the therapeutic addition of PC to the colonic mucus using slow release preparations is beneficial. The positive role of PC in this disease is still unclear; however, we have recently shown that PC has an intrinsic anti-inflammatory property. It could be demonstrated that the exogenous application of PC inhibits membrane-dependent actin assembly and TNF-α-induced nuclear NF-κB activation. We investigate here in more detail the hypothesis that the exogenous application of PC has anti-inflammatory properties.

Methods

PC species with different fatty acid side chains were applied to differentiated and non-differentiated Caco-2 cells treated with TNF-α to induce a pro-inflammatory response. We analysed TNF-α-induced NF-κB-activation via the transient expression of a NF-κB-luciferase reporter system. Pro-inflammatory gene transcription was detected with the help of a quantitative real time (RT)-PCR analysis. We assessed the binding of TNF-α to its receptor by FACS and analysed lipid rafts by isolating detergent resistant membranes (DRMs).

Results

The exogenous addition of all PC species tested significantly inhibited TNF-α-induced pro-inflammatory signalling. The expression levels of IL-8, ICAM-1, IP-10, MCP-1, TNF-α and MMP-1 were significantly reduced after PC pre-treatment for at least two hours. The effect was comparable to the inhibition of NF-kB by the NF-kB inhibitor SN 50 and was not due to a reduced binding of TNF-α to its receptor or a decreased surface expression of TNF-α receptors. PC was also effective when applied to the apical side of polarised Caco-2 cultures if cells were stimulated from the basolateral side. PC treatment changed the compartmentation of the TNF-α-receptors 1 and 2 to DRMs.

Conclusion

PC induces a prolonged inhibition of TNF-α-induced pro-inflammatory signalling. This inhibition may be caused by a shift of the TNF-α receptors at the surface to lipid rafts. Our results may offer a potential molecular explanation for the positive role of PC seen in clinical studies for the treatment of ulcerative colitis.

Oral phosphatidylcholine pretreatment alleviates the signs of experimental rheumatoid arthritis

INTRODUCTION

Phosphatidylcholine and phosphatidylcholine-derived metabolites exhibit anti-inflammatory properties in various stress conditions. We hypothesized that dietary phosphatidylcholine may potentially function as an anti-inflammatory substance and may decrease inflammatory activation in a chronic murine model of rheumatoid arthritis (collagen-induced arthritis).

METHODS

The experiments were performed on male DBA1/J mice. In groups 1 to 3 (n = 10 each), collagen-induced arthritis was induced by administration of bovine collagen II. In group 2 the animals were fed ad libitum with phosphatidylcholine-enriched diet as a pretreatment, while the animals of group 3 received this nourishment as a therapy, after the onset of the disease. The severity of the disease and inflammation-linked hyperalgesia were evaluated with semiquantitative scoring systems, while the venular leukocyte-endothelial cell interactions and functional capillary density were assessed by means of in vivo fluorescence microscopy of the synovial tissue. Additionally, the mRNA expressions of cannabinoid receptors 1 and 2, TNFalpha and endothelial and inducible nitric oxide synthase were determined, and classical histological analysis was performed.

RESULTS

Phosphatidylcholine pretreatment reduced the collagen-induced arthritis-induced hypersensitivity, and decreased the number of leukocyte-endothelial cell interactions and the extent of functional capillary density as compared with those of group 1. It also ameliorated the tissue damage and decreased inducible nitric oxide synthase expression. The expressions of the cannabinoid receptors and TNFalpha were not influenced by the phosphatidylcholine intake. Phosphatidylcholine-enriched food administrated as therapy failed to evoke the aforementioned changes, apart from the reduction of the inducible nitric oxide synthase expression.

CONCLUSIONS

Phosphatidylcholine-enriched food as pretreatment, but not as therapy, appears to exert beneficial effects on the morphological, functional and microcirculatory characteristics of chronic arthritis. We propose that oral phosphatidylcholine may be a preventive approach in ameliorating experimental rheumatoid arthritis-induced joint damage.

Anti-inflammatory effects of phosphatidylcholine

We recently showed that mucus from patients with ulcerative colitis, a chronic inflammatory disorder of the colon, is characterized by a low level of phosphatidylcholine (PC) while clinical studies reveal that therapeutic addition of PC using slow release preparations is beneficial. The positive role of PC in this disease is still elusive. Here we tested the hypothesis that exogenous application of PC has anti-inflammatory properties using three model systems. First, human Caco-2 cells were treated with tumor necrosis factor-alpha (TNF-alpha) to induce a pro-inflammatory response via activation of NF-kappaB. Second, latex bead phagosomes were analyzed for their ability to assemble actin in vitro, a process linked to pro-inflammatory signaling and correlating with the growth versus killing of mycobacteria in macrophages. The third system used was the rapid assembly of plasma membrane actin in macrophages in response to sphingosine 1-phosphate. TNF-alpha induced a pro-inflammatory response in Caco-2 cells, including 1) assembly of plasma membrane actin; 2) activation of both MAPKs ERK and p38; 3) transport of NF-kappaB subunits to the nucleus; and 4) subsequent up-regulation of the synthesis of pro-inflammatory gene products. Exogenous addition of most PCs tested significantly inhibited these processes. Other phospholipids like sphingomyelin or phosphatidylethanolamine showed no effects in these assays. PC also inhibited latex bead phagosome actin assembly, the killing of Mycobacterium tuberculosis in macrophages, and the sphingosine 1-phosphate-induced actin assembly in macrophages. TNF-alpha induces the activation of signaling molecules and the reorganization of the actin cytoskeleton in human intestinal cells. Exogenous application of PC blocks pro-inflammatory signaling in Caco-2 cells, in phagosomes in vitro and facilitates intracellular survival of mycobacteria. We provide further evidence that actin assembly by membranes is part of the pro-inflammatory response. Collectively, these results provide a molecular foundation for the clinical studies showing a beneficial effect of PC therapy in ulcerative colitis.

Beneficial effects of phosphatidylcholine during hindlimb reperfusion

BACKGROUND

Microcirculatory dysfunctions and mast cell (MC) reactions play important roles in hypoxic tissue injuries. The aims of this study were to characterize the effects of hindlimb ischemia-reperfusion (I-R) on the periosteal microcirculation and to define the consequences of systemic phosphatidylcholine (PC) therapy during this condition.

MATERIALS AND METHODS

Microcirculatory changes were visualized by means of fluorescence intravital videomicroscopy in anesthetized Wistar rats. There was 60 min of complete hindlimb ischemia followed by a 180-min reperfusion in the presence of PC treatment (50 mg/kg i.v.; in the second 10 min of reperfusion) or vehicle. Further two groups served as vehicle- or PC-treated sham-operated controls. The proportion of degranulated MCs and the leukocyte accumulation (myeloperoxidase, MPO assay) were determined in muscle biopsies.

RESULTS

I-R significantly increased the muscle MPO activity (from 14.94 to 63.45 mU/mg) and the proportion of degranulated MCs (to 82.5%). The periosteal capillary RBC velocity (RBCV) and the functional capillary density (FCD) had decreased, while the primary and secondary leukocyte-endothelial cell interactions had increased by the end of reperfusion (rolling from 20.8 to 40.0%, and firm adherence from 254 to 872 mm(-2)). PC treatment decreased the leukocyte rolling and sticking, preserved the FCD and improved the RBCV. The MC degranulation and MPO activity diminished significantly in the muscle layer.

CONCLUSIONS

PC administration improves I-R-induced periosteal microcirculatory dysfunctions and ameliorates secondary inflammatory reactions. Systemic PC treatment could offer a potential treatment modality during hypoperfusion or inflammatory conditions of the bones.

Electrophilic methyl groups present in the diet ameliorate pathological states induced by reductive and oxidative stress: a hypothesis

Reductive stress, characterised by an increased NADH:NAD+ ratio, may be as common and as important a consequence of redox imbalance as oxidative stress. It may also be an important predisposing cause of the generation of reactive oxygen species. Considerable experimental and indirect clinical evidence suggests that protection against reductive stress depends on biomolecules with electrophilic methyl groups (EMG) such as S-adenosylmethionine, betaine, carnitine and phosphatidylcholine. Pathological processes leading to reductive stress and their relief by such protective agents is reviewed and the proposed molecular mechanism is outlined. These and other EMG-containing biomolecules are part of the daily diet and may represent an important control system for redox balance.

Duodenal ulcer prevalence: experimental evidence for the possible role of dietary lipids

BACKGROUND AND AIMS

Mapping the geographical distribution of duodenal ulcer in relation to staple diets, and experiments on animal peptic ulcer models suggested that the lipid fraction in certain foodstuffs had a protective effect which was most marked in the lipid obtained from Horse gram (Dolichos biflorus). Lipid obtained from stored polished rice or rice bran was ulcerogenic. Further animal experiments were designed to investigate the protective and healing effects of Horse gram lipid (HGL) against peptic ulceration.

METHODS

Three effects were investigated in rats: (i) the protective effect of HGL on peptic ulceration produced by using pyloric ligation in combination with South Indian diet or rice bran oil, or by cysteamine, alcohol or aspirin; (ii) the effect of HGL on mast cell degranulation in response to pyloric ligation and rice bran oil; and (iii) the healing effect of HGL on acute gastric ulceration produced by alcohol, on chronic gastric ulceration produced by topical acetic acid or on chronic duodenal ulcer following cysteamine.

RESULTS

Horse gram lipid was shown to be protective and to promote ulcer healing in all the models used. Mast cell degranulation was inhibited.

CONCLUSION

The experiments confirm the presence of a lipid in certain staple foods that have protective and healing properties in experimental peptic ulcer animal models. The differences in the prevalence of duodenal ulceration between different regions in some developing countries with a high prevalence of Helicobacter pylori infection might be explained by the presence or absence of protective lipids or ulcerogenic factors in the staple diet.

Immunonutrition: role of biosurfactants, fiber, and probiotic bacteria

Phospholipids constitute an important part of cellular membranes, and membrane fluidity and permeability are dependent on the fatty acid composition of the phospholipid. The composition, which changes with aging and disease is, to a large degree, influenced by nutrient supply. Phospholipids have been effective in protecting cellular membranes such as those of the gastrointestinal tract to an extent not much different from that observed with external supply of established mucosa-protective drugs such as misoprostol and sucralfate. Polar lipids have also been shown to be effective in preventing microbial translocation. The effect is further potentiated by an external supply of probiotic fibers such as pectin, guar gum, and oat gum. These and many other fibers also have documented strong mucosa preventive effects. Prebiotic bacteria such as Lactobacillus plantarum have demonstrated a strong ability to preserve food and prevent spoilage. In addition, L. plantarum seems to not only preserve key nutrients such as omega-3 fatty acids, but also increases its content during storage conditions. L. plantarum alone or in combination with various fibers has demonstrated a strong ability to reduce and eliminate potentially pathogenic microorganisms both in vitro and in vivo. It has recently been shown that L. plantarum possesses the ability to adhere to and colonize intestinal mucosa. It seems unique among the lactobacilli for L. plantarum to use mannose-specific adhesins, uncommon among gram-positive, but common among gram-negative bacteria, which makes it possible that L. plantarum competes with gram-negative other potential pathogens for receptor sites at the mucosal cell surfaces. Additionally, L. plantarum seems to be effective in eliminating nitrate and producing nitric oxide. These functions of L. plantarum are among the reasons why it has been used in combination with various fibers and polar lipids to recondition the gastrointestinal mucosa. For the purpose of a L. plantarum-containing formula being produced and tried, a treatment policy is regarded as an extension of the immunonutrition program and called ecoimmunonutrition.

Econutrition and health maintenance — A new concept to prevent GI inflammation, ulceration and sepsis

The nutritional needs of the gastrointestinal mucosa per se has until today been largely neglected. It is a rather novel finding, that the lower part of the digestive tract is most dependent on luminal nutrition for maintaining its integrity, structure and function. Even the most complete parenteral nutrition (PN) regimen cannot, in the absence of adequate enteral nutrition (EN), fully prevent the development of mucosal atrophy in the lower part of the digestive tract, especially the colon. Nor can PN prevent the downregulation of the colon's many important functions. Increased microbial translocation and a predisposition to sepsis are consequences of inadequate luminal nutrition. Such developments can only be prevented by oral feeding and the local 'manufacturing' of essential nutrients in the colon. Probiotic bacteria are also important, especially with respect to the function of the colonic mucosa, which is the focus of this review.

Gastrointestinal surface protection and mucosa reconditioning

BACKGROUND

There is increasing evidence that preservation of the ecology of the gastrointestinal tract and the surface protection system--surfactants, mucus, and fiber--is important for the outcome in postoperative trauma patients, patients after bone marrow and liver transplantation, and patients with HIV or AIDS. Approximately 50% of the nourishment of the small intestine and > 80% of the nourishment of the large intestine comes from the lumen. This is especially deleterious to the large intestine. Within less than a week of intestinal starvation--even in the presence of intense parenteral nutrition--a mucosal atrophy is observed, promoting translocation of potentially pathogenic microorganisms. Enteral nutrition is crucial to the outcome in many of these conditions. If however, such a nutrition is based on simple carbohydrates, peptides, amino acids, or fatty acids, most of the nutrition administered will be absorbed in the upper gastrointestinal tract. Complex fibers and proteins can be regarded as nutrients especially destined to the lower gastrointestinal tract. They are fermented by the probiotic flora, normally colonizing the colonic mucosa, and the necessary nutrients: short-chain fatty acids and amino acids such as arginine and glutamine are produced at the level of the colonic mucosa. Careless antibiotic treatment reduces or eliminates this flora, induces local mucosal starvation, and makes the patients vulnerable to opportunistic infections and microbial intestinal translocation.

METHODS AND RESULTS

In this review the role of the different ingredients of the surface protection system are discussed. A program to recondition the intestines, particularly the colonic mucosa by resupply of species-specific lactobacilli, surfactants, amino acids (especially glutamine), and oat fiber (beta-glucans) is suggested. Extensive experience in animal models and early experience in a patient population are summarized and discussed. Oat has been chosen as a substrate for fermentation because it contains 100 times more of membrane lipids (surfactants) than any other food, has a favorable amino acid pattern (rich in glutamine), and is rich in water-soluble, fermentable-fiber beta-glucans. More than 1000 isolates of human-specific lactobacilli have been studied. Some strains, especially those of plantarum type, have proven effective in colonizing the colonic mucosa, suppressing the potentially pathogenetic flora, and may have other probiotic effects as well.

CONCLUSION

A totally new enteral formula has been designed based on probiotic bacteria and fiber and aimed at colonizing the intestinal mucosa with a local probiotic effect and fermentation of fiber.

Demonstration of a phospholipid-rich zone in the human gastric epithelium damaged by Helicobacter pylori

BACKGROUND

Recently, a hydrophobic layer has been shown by the contact angle method in human gastric biopsy specimens. The aim of this study was to show the existence of a phospholipid-rich layer in the human gastric epithelium and to investigate the influence of Helicobacter pylori on these structures.

METHODS

Biopsy specimens from the gastric antrum were obtained during gastroscopy from patients with normal gastric mucosa as well as from patients with H. pylori-positive gastritis for electron microscopical and histological examination. Structures reacting with a phospholipid-selective stain, iodoplatinate were analyzed by electron microscopy and electron-dispersive x-ray microanalysis.

RESULTS

Both methods revealed the morphological existence of a phospholipid-rich zone covering the human gastric epithelial layer. Reaction products could be localized within the cells, at the epithelium closely associated with the surface, and in connection with the mucus. In infected tissue, H. pylori affects iodoplatinate-reactive material within the mucous layer and material covering the epithelium.

CONCLUSIONS

The phospholipid-rich zone in the apical region of surface mucous cells is likely to represent an important factor of the gastric protective system in humans. The destruction of this hydrophobic layer may result in a reduction of hydrophobicity giving access to gastric acid.

Green banana protection of gastric mucosa against experimentally induced injuries in rats. A multicomponent mechanism?

The protective capacities of fresh green (unripe) sweet bananas and of phosphatidylcholine and pectin (banana ingredients) against acute (ethanol- or indomethacin-induced) and chronic (indomethacin-induced) gastric mucosal lesions were evaluated in rats. Banana pulp was mixed with saline and given by gavage, as a pretreatment in a single dose. The identical protocol was used for pectin and phosphatidylcholine solution, and the dosages were adjusted to equal the amount of ingredients in the banana mixture, but higher concentrations were also given. The banana suspension reduced acute lesions, as did pectin and phosphatidylcholine in higher concentrations, but in concentrations as in fresh fruit no protective effects were observed except by pectin against indomethacin injury. In the model of chronic ulcers the banana suspension provided an incomplete and temporary protective effect. We conclude that the protective capacity of fresh green sweet bananas cannot be confined to only one active component. Pectin and phosphatidylcholine may protect gastric mucosa by strengthening the mucous-phospholipid layer, but the mechanism of protection afforded by bananas has to be further elucidated.