Preservation of gastric functional activity in a stress model of functional dyspepsia by the herbal preparation, STW5

One of the main gastric disorders encountered in functional dyspepsia (FD) is a delay in gastric emptying and changes in gastric functional activity. The aim of the present study was to observe whether the established efficacy of the herbal preparation STW5 in FD could owe its beneficial effects at least in part to preservation of gastric emptying and other parameters of gastric function. STW5 consists of standardized extracts of Iberis amara, Melissa officinalis, Matricaria recutita, Carum carvi, Mentha piperita, Angelica archangelica, Silybum marianum, Chelidonium majus, and Glycyrrhiza glabra. To simulate experimentally a model of FD resembling the clinical situation where FD has been attributed to emotional stress in early life, followed by further exposure to stress later in life, rats were subjected to neonatal maternal separation, followed by restraint stress in adulthood. The restraining sessions were carried out for 90 min/day for 1 week. During these sessions animals were given STW 5 orally in daily doses of 2 and 5 ml/Kg. One day after the last session, the gastric emptying time of the animals was determined using a phenol red meal. Rats subjected to stress showed marked delay in gastric emptying, an effect which was counteracted dose dependently by STW5. In a separate group of rats, blood samples were taken for assaying stress hormones and fundus strips were removed after sacrifice to test their sensitivity ex-vivo towards carbachol, serotonin, adrenaline and KCl. Sensitivity of the fundus to these agents was markedly depressed by stress, but tended to be normalized after treatment with STW5. The stress hormone levels were elevated by the model but tended to be normalized by the herbal preparation. The results contribute to our understanding of the beneficial properties of STW 5 in FD.