RESUMEN
UNLABELLED: CONTEXT. Ribes nigrum L. (Grossulariaceae) is among the most commonly used herbal medicines and it is popularized for its alleged tonic effect and curative and restorative properties. The current practice of identifying herbal extracts is by measuring the concentration of the main botanicals. Their concentrations are used to characterize the herbal preparations and fingerprinting is recommended by the main Pharmacopeias as a potential and reliable strategy for the quality control of complex mixtures. OBJECTIVE: The aim of this research was to perform an analytical study of R. nigrum bud-preparations, in order to identify and quantify the main bioactive compounds, obtaining a specific chemical fingerprint to evaluate the single class contribution to herbal preparation phytocomplex. MATERIALS AND METHODS: The same analyses were performed using a high-performance liquid chromatograph-diode array detector both on University lab preparations and on commercial preparations from different Italian locations. Different chromatographic methods were used to analyse the macerated samples, two for polyphenols and one for terpenic compounds. RESULTS. Ribes nigrum was identified as a rich source of anti-inflammatory and antioxidant compounds. The observed analytical firgerprint demonstrated that these bud-preparations represent a rich source of terpenic and polyphenolic compounds, especially catechins and phenolic acids. DISCUSSION AND CONCLUSION: Analytical fingerprinting could be an important tool to study the assessment of chemical composition and bioactivities of plant-derived products, helping to find new sources of natural health-promoting compounds: this study allowed the development of an effective tool for quality control through botanical fingerprinting of bud preparations.
Asunto(s)
Antiinflamatorios/análisis , Antioxidantes/análisis , Cromatografía Líquida de Alta Presión , Extractos Vegetales/análisis , Ribes/química , Antiinflamatorios/clasificación , Antioxidantes/clasificación , Catequina/análisis , Hidroxibenzoatos/análisis , Fitoterapia , Componentes Aéreos de las Plantas , Extractos Vegetales/clasificación , Plantas Medicinales , Polifenoles/análisis , Terpenos/análisisRESUMEN
There is a lack of published microsatellite data which characterizes Ribes spp. To address this, an initial study of simple sequence repeat (SSR) variation was undertaken in 41 cultivars belonging to four species of the genus Ribes to evaluate its genetic variability. The cultivars were collected in Piedmont, northwest Italy, together with one cultivar from Switzerland. Twenty SSRs were screened for amplification and polymorphism. Seven failed to amplify, and therefore the remaining 13 were selected and used to fingerprint all the cultivars. Microsatellite analysis resulted in the identification of 38 genotypes, suggesting the existence of possible clonal genotypes and synonyms. Among the cultivars analyzed, two tetraploid accessions were found. The evaluation of genetic variability in Ribes is of fundamental importance for future nutritional breeding programs and to preserve genetic resources, as cultivar characterization permits better management of plant collections.
Asunto(s)
ADN de Plantas/genética , Repeticiones de Microsatélite/genética , Ribes/genética , Filogenia , Polimorfismo Genético , Ribes/clasificaciónRESUMEN
The glutathione (GSH) antioxidant system is foremost among the cellular protective mechanisms. Depletion of this small molecule is a common consequence of increased formation of reactive oxygen species during increased cellular activities. This phenomenon can occur in the lymphocytes during the development of the immune response and in the muscular cells during strenuous exercise. It is not surprising that so much research has been done, and is still being done on this small tripeptide molecule. Whey protein concentrate has been shown to represent an effective and safe cysteine donor for GSH replenishment during GSH depletion in immune deficiency states. Cysteine is the crucial limiting amino acid for intracellular GSH synthesis. Animal experiments showed that the concentrates of whey proteins also exhibit anti-carcinogenesis and anticancer activity. They do this via their effect on increasing GSH concentration in relevant tissues, and may have anti-tumor effect on low volume of tumor via stimulation of immunity through the GSH pathway. It is considered that oxygen radical generation is frequently a critical step in carcinogenesis, hence the effect of GSH on free radicals as well as carcinogen detoxification, could be important in inhibiting carcinogenesis induced by a number of different mechanisms. Case reports are presented which strongly suggest an anti-tumor effect of a whey protein dietary supplement in some urogenital cancers. This non toxic dietary intervention, which is not based on the principles of current cancer chemotherapy, will hopefully attract the attention of laboratory and clinical oncologists.
Asunto(s)
Glutatión/metabolismo , Proteínas de la Leche/uso terapéutico , Neoplasias/terapia , Animales , Antineoplásicos , Ensayos Clínicos como Asunto , Cisteína/administración & dosificación , Cisteína/uso terapéutico , Suplementos Dietéticos , Femenino , Humanos , Masculino , Proteínas de la Leche/administración & dosificación , Proteínas de la Leche/química , Neoplasias/fisiopatología , Proteína de Suero de LecheRESUMEN
The chronic fatigue syndrome (CFS) is typically associated or follows a recognized or presumed infection. Abnormalities of both humoral and cellular immunity have been demonstrated in a substantial proportion of patients with CFS. The most consistent findings are of impaired lymphocyte responses to mitogen. As an antioxidant, glutathione (GSH) is essential for allowing the lymphocyte to express its full potential without being hampered by oxiradical accumulation. Hence, protracted challenge of the immunocytes may lead to cellular GSH depletion. Because GSH is also essential to aerobic muscular contraction, an undesirable competition for GSH precursors between the immune and muscular systems may develop. It is conceivable that the priority of the immune system for the survival of the host has drawn to this vital area the ever-diminishing GSH precursors, thus depriving the skeletal muscle of adequate GSH precursors to sustain a normal aerobic metabolism resulting in fatigue and eventually myalgia.
Asunto(s)
Síndrome de Fatiga Crónica/etiología , Glutatión/metabolismo , Sistema Inmunológico/metabolismo , Músculo Esquelético/metabolismo , Ejercicio Físico , HumanosRESUMEN
Glutathione (GSH) concentration is high in most tumour cells and this may be an important factor in resistance to chemotherapy. Previous in-vitro and animal experiments have shown a differential response of tumour versus normal cells to various cysteine delivery systems. More specifically, an in-vitro assay showed that at concentrations that induce GSH synthesis in normal human cells, a specially prepared whey protein concentrate, Immunocal, caused GSH depletion and inhibition of proliferation in human breast cancer cells. On the basis of this information five patients with metastatic carcinoma of the breast, one of the pancreas and one of the liver were fed 30 grams of this whey protein concentrate daily for six months. In six patients the blood lymphocyte GSH levels were substantially above normal at the outset, reflecting high tumour GSH levels. Two patients (#1, #3) exhibited signs of tumour regression, normalization of haemoglobin and peripheral lymphocyte counts and a sustained drop of lymphocyte GSH levels towards normal. Two patients (#2, #7) showed stabilisation of the tumour, increased haemoglobin levels. In three patients (#4, #5, #6,) the disease progressed with a trend toward higher lymphocyte GSH levels. These results indicate that whey protein concentrate might deplete tumour cells of GSH and render them more vulnerable to chemotherapy.
Asunto(s)
Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/secundario , Glutatión/metabolismo , Proteínas de la Leche/uso terapéutico , Proteínas de Neoplasias/antagonistas & inhibidores , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/inmunología , Adenocarcinoma/metabolismo , Adenocarcinoma/secundario , Adulto , Anciano , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/inmunología , Carcinoma/tratamiento farmacológico , Carcinoma/inmunología , Carcinoma/metabolismo , Carcinoma/patología , Carcinoma Ductal de Mama/tratamiento farmacológico , Carcinoma Ductal de Mama/inmunología , Carcinoma Ductal de Mama/patología , Cisteína/fisiología , Femenino , Hemoglobinas/análisis , Humanos , Lactalbúmina/administración & dosificación , Lactalbúmina/farmacología , Lactoferrina/administración & dosificación , Lactoferrina/farmacología , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/inmunología , Neoplasias Hepáticas/secundario , Recuento de Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Persona de Mediana Edad , Proteínas de la Leche/química , Proteínas de la Leche/farmacología , Metástasis de la Neoplasia , Proteínas de Neoplasias/metabolismo , Neoplasias Primarias Desconocidas , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/inmunología , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , Calidad de Vida , Albúmina Sérica Bovina/administración & dosificación , Albúmina Sérica Bovina/farmacología , Proteína de Suero de LecheRESUMEN
On the basis of numerous animal experiments, a pilot study was undertaken to evaluate the effect of undenatured, biologically active, dietary whey protein in 3 HIV-seropositive individuals over a period of 3 months. Whey protein concentrate was prepared so that the most thermosensitive proteins, such as serum albumin which contains 6 glutamylcysteine groups, would be in undenatured form. Whey protein powder dissolved in a drink of the patient's choice was drunk cold in quantities that were increased progressively from 8.4 to 39.2 g per day. Patients took whey proteins without adverse side effects. In the 3 patients whose body weight had been stable in the preceding 2 months, weight gain increased progressively between 2 and 7 kg, with 2 of the patients reaching ideal body weight. Serum proteins, including albumin, remained unchanged and within normal range, indicating that protein replenishment per se was not likely the cause of increased body weight. The glutathione content of the blood mononuclear cells was, as expected, below normal values in all patients at the beginning of the study. Over the 3-month period, glutathione levels increased in all 3 cases. In conclusion, these preliminary data indicate that, in patients who maintain an adequate total caloric intake, the addition of "bioactive" whey protein concentrate as a significant portion of total protein intake increases body weight and shows elevation of glutathione (GSH) content of mononuclear cells toward normal levels. This pilot study will serve as a basis for a much larger clinical trial.
Asunto(s)
Alimentos Fortificados , Seropositividad para VIH/terapia , Proteínas de la Leche/uso terapéutico , Peso Corporal/efectos de los fármacos , Glutatión/sangre , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Masculino , Proyectos Piloto , Proteína de Suero de LecheRESUMEN
This study compared the effects of different sources of whey protein concentrate (20 g/100 g diet) and of casein on the spleen, liver, and heart glutathione content of C3H/HeJ mice, and on the immune response of their spleen cells to sheep red blood cells. Body weight curves were similar in all dietary groups. Our data indicate that the humoral immune response is highest in mice fed a dietary whey protein concentrate exhibiting the highest solubility (undenatured conformation) and a greater relative concentration of the thermolabile bovine serum albumin and immunoglobulins. In addition, the mice fed this type of whey protein concentrate exhibit higher levels of tissue glutathione. The presence in the serum albumin fraction of glutamylcysteine groups (rare in food protein) and the specific intramolecular bond as related to the undenatured conformation of the molecule are considered to be key factors in the glutathione-promoting activity of the protein mixture.
Asunto(s)
Formación de Anticuerpos/efectos de los fármacos , Proteínas en la Dieta/farmacología , Glutatión/fisiología , Proteínas de la Leche/farmacología , Animales , Caseínas/inmunología , Caseínas/farmacología , Proteínas en la Dieta/inmunología , Glutatión/biosíntesis , Corazón/efectos de los fármacos , Técnica de Placa Hemolítica , Calor , Hígado/química , Hígado/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C3H/inmunología , Leche/análisis , Proteínas de la Leche/inmunología , Proteínas de la Leche/aislamiento & purificación , Miocardio/química , Conformación Proteica , Desnaturalización Proteica , Bazo/química , Bazo/efectos de los fármacos , Bazo/inmunología , Relación Estructura-Actividad , Proteína de Suero de LecheRESUMEN
Epidemiological and experimental studies suggest that dietary milk products may exert an inhibitory effect on the development of several types of tumors. Some recent experiments in rodents indicate that the antitumor activity of the dairy products is in the protein fraction and more specifically in the whey protein component of milk. We and others have demonstrated that whey protein diets result in increased glutathione (GSH) concentration in a number of tissues, and that some of the beneficial effects of whey protein intake are abrogated by inhibition of GSH synthesis. Whey protein is particularly rich in substrates for GSH synthesis. We suggest that whey protein may be exerting its effect on carcinogenesis by enhancing GSH concentration.
Asunto(s)
Proteínas en la Dieta/administración & dosificación , Proteínas de la Leche/administración & dosificación , Neoplasias/prevención & control , Animales , Humanos , Proteína de Suero de LecheRESUMEN
Intestinal complications following strenuous, protracted physical activity have been increasingly recognized. Diarrhea, sometimes associated with blood loss, described in marathon runners does not appear to be a common diarrhea but rather the clinical expression of ischemic enteropathy. On the basis of experimental evidence and some clinical data, it is suggested that prefeeding an elemental semi-hydrolyzed diet might reduce the incidence and severity of this intestinal handicap in marathon runners. Perhaps, more importantly, the potentially adverse effects of acute ischemic enteropathy on the cardiovascular system might be accordingly reduced.
Asunto(s)
Intestinos/irrigación sanguínea , Isquemia/etiología , Carrera , Sistema Cardiovascular/fisiopatología , Diarrea/etiología , Alimentos Formulados , Hemorragia Gastrointestinal/etiología , Humanos , Isquemia/prevención & control , Modelos BiológicosRESUMEN
This study investigated the influence of two formula diets containing 20 g/100 g diet of either whey protein concentrate or casein, or Purina mouse chow on 1,2-dimethylhydrazine (DMH)-induced colon carcinoma in A/J mice. Four weeks after the 24th DMH treatment the incidence of tumour and tumour area in the whey protein-fed mice was substantially less in comparison to either the casein or Purina groups. The Purina group exhibited the greatest tumour burden. At the end of the experiment all animals continuously fed the whey protein diet were found to be alive, whereas 33% of those on the casein or Purina diet had died. Animals fed Purina diet for 20 weeks and then switched to either milk protein diet for a further 8 weeks exhibited a decrease in tumour burden as compared to those animals fed the Purina diet continuously. Body weights were similar in all dietary groups. In conclusion, a whey protein diet appears to significantly influence the development of chemically induced colon tumours and the short-term survival of mice.
Asunto(s)
Adenocarcinoma/prevención & control , Neoplasias del Colon/prevención & control , Dimetilhidrazinas , Metilhidrazinas , Proteínas de la Leche/farmacología , Adenocarcinoma/inducido químicamente , Animales , Peso Corporal/efectos de los fármacos , Caseínas/farmacología , División Celular/efectos de los fármacos , Neoplasias del Colon/inducido químicamente , Femenino , RatonesRESUMEN
This study compared the effects of a whey-rich diet (20 g/100 g diet), with that of Purina mouse chow or casein-rich diet (20 g/100 g diet), on the liver and heart glutathione content and on the survival of old male C57BL/6NIA mice. The study was performed during a limited observation period of 6.3 months. In mice fed the whey protein-rich diet between 17 months and 20 months of age, the heart tissue and liver tissue glutathione content were enhanced significantly above the corresponding values of the casein diet-fed and Purina-fed mice. Mice fed the whey protein diet at the onset of senescence at 84 weeks, exhibited increased longevity as compared to mice fed Purina mouse chow over the 6.3 month observation period extending from the age of 21 months (corresponding to a human age of 55 years) to 26-27 months of age (corresponding to a human age of 80 years), during which time 55% mortality was observed. The corresponding mean survival time of mice fed the defined casein diet is almost identical to that of Purina-fed controls. Body weight curves were similar in all three dietary groups. Hence a whey protein diet appears to enhance the liver and heart glutathione concentration in aging mice and to increase longevity over a 6.3 month observation period.
Asunto(s)
Envejecimiento/fisiología , Proteínas en la Dieta/farmacología , Glutatión/metabolismo , Proteínas de la Leche/farmacología , Animales , Peso Corporal/efectos de los fármacos , Dieta , Técnica de Placa Hemolítica , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína de Suero de LecheRESUMEN
A whey protein diet has been shown to enhance splenic immune response to sheep red blood cells (SBRC) in mice. This study was designed to investigate the influence of the type of dietary protein on the biliary secretory IgA. A/J mice were fed defined formula diets containing either 20% whey protein, or 20% casein. Another group was fed Purina mouse chow. After 3 weeks of dietary treatment the body weight of each mouse was recorded and the gall-bladder was removed and its whole content analyzed by ELISA to determine S-IgA secretion. Body weight curves were similar in all dietary groups; higher biliary levels of S-IgA appeared in the whey protein fed mice than in the casein (p less than 0.025) or purine (p less than 0.025) fed mice. Dietary protein type may have a direct influence on the immune response in the gastrointestinal tract, without affecting body weight.
Asunto(s)
Bilis/inmunología , Inmunoglobulina A Secretora/análisis , Proteínas de la Leche/farmacología , Animales , Peso Corporal , Caseínas/farmacología , Ensayo de Inmunoadsorción Enzimática , Femenino , Ratones , Proteína de Suero de LecheRESUMEN
The recognition of potentially noxious physiological substances in the intestinal milieu, prompted the use of an "elemental" semi-hydrolysed formula diet in the prophylaxis of experimental acute ischemic enteropathy. An elemental diet protects the intestinal mucosa of rodents from radiation injury and facilitates mucosal healing. Clinical trials have shown the benefits of this form of treatment in the prevention of acute radiation enteritis and therapy of delayed enteropathy and Crohn's disease.
Asunto(s)
Alimentos Formulados , Enfermedades Intestinales/dietoterapia , Enfermedad Aguda , Animales , Niño , Enfermedad de Crohn/dietoterapia , Perros , Humanos , Enfermedades Intestinales/etiología , Intestinos/irrigación sanguínea , Isquemia , Ratones , Traumatismos por Radiación/complicaciones , Traumatismos por Radiación/etiología , Traumatismos Experimentales por Radiación/complicaciones , Radioterapia/efectos adversos , RatasRESUMEN
The spleen cells immune response to sheep red blood cells of C3H/HeJ mice fed a 20 g whey protein/100 g diet is substantially higher than that of mice fed an equivalent casein diet of similar nutritional efficiency. The present study indicates that the observed immunoenhancing effect of the whey protein mixture is dependent on the overall amino acid pattern resulting from the contribution of all its protein components. Whey protein contains substantially more cysteine than casein. Dietary cysteine is considered to be a rate limiting substrate for the synthesis of glutathione which is necessary for lymphocyte proliferation. Our studies show that enhancement of host humoral immune response is associated with greater and more sustained production of splenic glutathione during the antigen driven clonal expansion of the lymphocyte in whey protein fed mice in comparison to mice fed the equivalent casein or the cysteine-enriched casein diet. Hence the efficiency of dietary cysteine in inducing supernormal glutathione levels is greater when it is delivered in the whey protein than as free cysteine. Administration of S-(n-butyl) homocysteine sulfoximine, which reduces splenic glutathione level by half, produces a 4-5 fold drop in the humoral immune response of whey protein diet-fed mice. This is further evidence of the important role of glutathione in the immunoenhancing effect of dietary whey protein.
Asunto(s)
Dieta , Glutatión/metabolismo , Sistema Inmunológico/metabolismo , Proteínas de la Leche/administración & dosificación , Bazo/inmunología , Animales , Peso Corporal , Conducta Alimentaria , Glutatión/fisiología , Masculino , Ratones , Ratones Endogámicos C3H , Bazo/metabolismo , Proteína de Suero de LecheRESUMEN
The recognition of potentially noxious physiologic substances in the intestinal milieu prompted the use of an "elemental" semihydrolyzed formula diet in the prophylaxis of experimental acute ischemic enteropathy. Elemental diets have been used in the management of a variety of digestive diseases. An elemental diet protects the intestinal mucosa of rodents from radiation injury and facilitates mucosal healing. Clinical trials have shown the benefits of this form of treatment in the prevention of acute radiation enteropathy and in the therapy for delayed radiation enteropathy and Crohn's disease.
Asunto(s)
Enfermedad de Crohn/terapia , Nutrición Enteral , Alimentos Formulados , Mucosa Intestinal/irrigación sanguínea , Isquemia , Traumatismos por Radiación , Enfermedad Aguda , Humanos , Mucosa Intestinal/efectos de la radiación , Isquemia/prevención & control , Isquemia/terapia , Traumatismos por Radiación/prevención & control , Traumatismos por Radiación/terapiaRESUMEN
Human milk has the lowest concentration of protein of any mammalian species. Since the rate of growth of the offspring is negatively related to the protein content of the milk, the time required to double the birth weight is greater in the infant than in any other mammal in which it has been measured. Similarly, in weaned animals, a low protein diet increases the time required to reach maximal growth, senescence and natural death. Human milk protein has the highest whey protein to casein ratio than the milk of any other mammalian species. Our previous experiments have shown that mice fed a 20% whey protein diet exhibit increased resistance to Streptococcus pneumoniae and a humoral immune response significantly higher than that of mice fed most of the commercially available animal and plant proteins in nutritionally similar and adequate formula diets. Other studies have demonstrated that mean and maximal longevity of hamsters fed a 20% whey protein diet is increased in comparison with those fed commercial laboratory feed or a supplemented casein diet of similar nutritional efficiency. Thus, the low protein content and the prevalence of whey protein, which are characteristic features of human milk, are both associated with slow body growth and increased longevity. For human infants, mother's milk is the first and, for most, the only food ingested for a considerable period of time. We, therefore, propose that a trace of Nature's design for the offspring and the evolution of the species can be found in mother's milk.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Evolución Biológica , Proteínas de la Leche/análisis , Leche Humana/análisis , Animales , Femenino , Crecimiento , Humanos , Longevidad , Leche Humana/fisiologíaRESUMEN
The plaque-forming cell response to sheep red blood cells was found to be enhanced in mice fed a formula diet containing 20 g lactalbumin/100 g diet in comparison to mice fed equivalent formula diets of similar nutritional efficiency containing 20 g/100 g diet of either casein, soy, wheat or corn protein, egg albumin, beef or fish protein, Spirulina maxima, or Scenedesmus protein, or Purina mouse chow. This effect was manifest after 2 weeks and persisted for at least 8 weeks of dietary treatment. Mixing lactalbumin with either casein or soy protein in a 20 g protein/100 g diet formula significantly enhanced the immune response in comparison to that of mice fed diets containing 20% soy protein or casein.
Asunto(s)
Adyuvantes Inmunológicos , Proteínas de la Leche/inmunología , Animales , Células Productoras de Anticuerpos/inmunología , Proteínas en la Dieta/inmunología , Proteínas en la Dieta/farmacología , Eritrocitos/inmunología , Lactalbúmina/inmunología , Lactalbúmina/farmacología , Masculino , Ratones , Ratones Endogámicos C3H , Proteínas de la Leche/farmacología , Proteína de Suero de LecheRESUMEN
This study investigates the influence of two formula diets containing 20 g/100 g diet of either whey protein concentrate or casein or Purina mouse chow, on the humoral immune responsiveness and dimethylhydrazine induced colon carcinogenesis in A/J mice. After 20 weeks of dimethylhydrazine treatment, the number of plaque forming cells per spleen, following intravenous inoculation with 5 X 10(6) sheep red blood cells, was nearly three times greater in the whey protein-fed group than in the casein-fed mice although both values were substantially below normal. After 24 weeks of dimethylhydrazine treatment the incidence of tumors in the whey protein-fed mice was substantially lower than that in mice fed either the casein or Purina diet. Similarly, the tumor area was less in the whey protein group in comparison to either the casein or Purina groups, with some difference between casein and Purina groups. Body weight curves were similar in all dietary groups. In conclusion, a whey protein diet appears to significantly inhibit the incidence and growth of chemically induced colon tumors in mice.
Asunto(s)
Neoplasias del Colon/prevención & control , Proteínas en la Dieta/farmacología , Proteínas de la Leche/farmacología , 1,2-Dimetilhidrazina , Aminoácidos/análisis , Animales , Carcinógenos , Neoplasias del Colon/inducido químicamente , Neoplasias del Colon/patología , Dimetilhidrazinas , Femenino , Ratones , Ratones Endogámicos A , Proteínas de la Leche/análisis , Minerales/análisis , Vitaminas/análisis , Proteína de Suero de LecheRESUMEN
The specific susceptibility of the intestinal mucosa to low blood flow states is related to the "physiologic" makeup of the intestinal milieu. Pancreatic proteases appear to play a crucial role in the ischemic autodigestion of the intestinal mucosa. Moreover, trypsin can activate the conversion of xanthine dehydrogenase into superoxide radicals producing xanthine oxidase. Oxygen-derived free radicals account for at least part of the damage to the postischemic intestinal mucosa.