Mohamed T. Khayyal

• PhD
• Professor Emeritus at Cairo University

Astaxanthin is a naturally occurring carotenoid with high anti-oxidant properties, but it is a very lipophilic compound with low oral bioavailability. This study was conducted to compare the pharmacokinetic parameters of a novel astaxanthin preparation based on micellar solubilization technology, NovaSOL® 400-mg capsules (Test product), and those o...

Aims: Depression is one of the common neurological comorbidities in patients with inflammatory bowel disease (IBD). The current study aimed to investigate the potential impact of niacin on colitis-induced depressive-like behavior in rats. Materials and methods: Animals were given 5 % dextran sulfate sodium (DSS) in drinking water for one week to...

Inflammatory bowel disease (IBD) represents a chronic inflammation of the gastrointestinal tract characterized by an overreaction of immune responses and damage at the intestinal mucosal barrier. P-glycoprotein (P-gp) plays a key role to protect the intestinal barrier from xenobiotic accumulation and suppressing excessive immune responses. Therefor...

Background Exposure to stress has been related to disturbance in 5‐hydroxytryptamine (5‐HT) signaling in the brain‐gut axis and is considered as a major predisposing factor for the development of irritable bowel syndrome (IBS). The present study aimed to investigate the possible involvement of 5‐HT and some other stress‐related parameters in the ef...

Background The standardized herbal preparation, STW 5, is effective clinically in functional gastrointestinal disorders and experimentally in ulcerative colitis (UC). The present study explores whether the beneficial effect of STW 5 involves influencing the intestinal microbiota. Methods UC was induced in Wistar rats by feeding them 5% dextran sod...

Background Xanthohumol is known to exert anti-inflammatory properties but has poor oral bioavailability. Using advanced micellization technology, it has been possible to markedly enhance its bioavailability. Purpose In the present study, we compared the chronic anti-inflammatory activities of native and micellar xanthohumol in the rat adjuvant art...

Background: Proton pump inhibitors are often used to prevent gastro-intestinal lesions induced by nonsteroidal anti-inflammatory drugs. However, they are not always effective against both gastric and duodenal lesions and their use is not devoid of side effects. Aim: To explore the mechanisms mediating the clinical efficacy of STW 5 in gastro-duo...

Intestinal mucositis is a common side effect during radiotherapy that could be largely prevented by compounds possessing anti-inflammatory or anti-oxidant properties, including extracts of propolis containing a high proportion of flavonoids. A specially formulated aqueous extract of propolis (PWE) has been prepared in such a way to preclude the inc...

Dunaliella salina (D. salina) is one of the most common microalgae that is used as human food. It is isolated from the salty lakes in El-Fayoum and Lake of Bardawil-Sinai in Egypt and can withstand very high concentrations of salt: The potentiality of D. salina, a unicellular biflagellate green alga to protect against intestinal injury induced afte...

Compounds that prevent radiation‐induced mucositis may offer new therapeutic strategies for maintaining intestinal integrity in patients undergoing radiotherapy. A specially formulated chamomile extract was studied with the hope of proving efficacy in this regard. Intestinal mucositis was induced in rats by exposing them to whole body gamma‐irradia...

Objective: Native extracts of curcumin and boswellia are known to exert antiinflammatory properties but have poor bioavailability when given orally. Using advanced micellation technology, it has been possible to produce stable solubilisates of these extracts with markedly enhanced bioavailability. In the present study, we compared the chronic anti...

The use of herbal medicines is favored today among many beliefs that they have fewer side effects than conventional synthetic drugs. Many were empirically prepared with various claims of activity to treat disease and enhance general wellbeing but without sufficient evidence of usefulness. It is therefore essential to encourage the cooperation betwe...

Native extracts of Curcumin are known to exert anti-inflammatory properties, but have poor bioavailability when given orally. Through advanced micellation technology, it has been possible to produce stable solubilisates of these extracts, thereby markedly enhancing their bioavailability and consequently reducing the orally administered dose and red...

Effect of the Herbal Preparation, STW 5, on the Microbiome in an Experimental Model of Functional Dyspepsia

The herbal preparation STW 5 is a standardized multi-component mixture of hydro-alcoholic extracts of bitter candytuft, lemon balm, chamomile, caraway fruit, peppermint leaf, Angelica root, milk thistle, celandine herb, and licorice root. It has been used successfully clinically in functional dyspepsia [1] and irritable bowel syndrome [2]. We have...

Gastro-esophageal reflux disease (GERD) is one of the most common disorders in gastroenterology. Patients present with or without increased acid exposure indicating a non-uniform etiology. Thus the common treatment with proton pump inhibitors (PPIs) fails to control symptoms in up to 40% of patients. To further elucidate the pathophysiology of the...

The ability of a specially prepared water propolis extract (PWE) to preserve the functional activity of the intestinal mucosa after radiation exposure was studied. PWE was given orally (650mg/kg) to rats five days prior to irradiation by 6Gy and continued for further two days. Rats were sacrificed 24h later, intestinal segments were examined histol...

The present study aims to show whether the beneficial effects of the herbal preparation STW 5 (Iberogast®) in functional dyspepsia (FD) could be partly due to preservation of gastric emptying and function. STW 5 consists of standardized extracts of Iberis amara, Melissa officinalis, Matricaria recutita, Carum carvi, Mentha x piperita, Angelica arch...

Protonenpumpenhemmer (PPI) sind doe Hauptbehandlung für die Gastroösophageale Reflux Erkrankung (GERD), aber bis zu 40% der Patienten erreichen keine komplette Symptomfreiheit. Deshalb ist eine weitere Suche nach neuen therapeutischen Targets & zusätzliche Behandlungsoptionen notwendig. Kürzlich wurde gezeigt, dass das pflanzliche Kombinationspräpa...

The anti-inflammatory potential and vasoprotective effects of an Iberis amara extract in a rat model of arthritis were investigated. I. amara, or bitter candytuft, has long been known for its anti-inflammatory properties on account of its active constituents, including cucurbitacins, kaempferol, and sinapic acid. The present study was intended to e...

Earlier studies showed that the compatible solute ectoine (1) given prophylactically before induction of colitis by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats prevented histological changes induced in the colon and the associated rise in inflammatory mediators. This study was therefore conducted to investigate whether ectoine (1) and its 5α-...

Proton pump inhibitors (PPI) present the main treatment for gastroesophageal reflux disease (GERD), but up to 40% of patients do not achieve adequate symptom control. Therefore the search continues for new therapeutic targets and additional treatment options. We recently demonstrated that the multi-component herbal preparation STW5 affects multiple...

Introduction. Clinical studies have shown that the etiology of FD is related to adverse psychological experiences in early life1,2, especially when enhanced later by stressful conditions in adulthood3,4. The present study was designed to expose animals to stress early in life (neonatal maternal separation, NMS) followed by exposure to acute stress...

Many screening procedures for agents with potential usefulness in functional dyspepsia (FD) rely on animals exposed to stress early in life (neonatal maternal separation, NMS) or in adulthood (restraint stress, RS). Since many clinical cases of FD have been associated with stress in early life followed by stress in adulthood, a sequential model sim...

Clinical evidence suggests that stress in early life followed by stress in adulthood could lead to FD1,2, involving derangement in gastric function. We developed a sequential stress model for functional dyspepsia (FD) to try and simulate the clinical situation. Weanling rats were subjected to neonatal maternal stress (NMS) where they were removed f...

Mitochondrial dysfunction plays an important role in brain aging and has emerged to be an early event in Alzheimer's disease (AD), contributing to neurodegeneration and the loss of physical abilities seen in patients suffering from this disease. We examined mitochondrial dysfunction in a cell culture model of AD (PC12APPsw cells) releasing very low...

Patients undergoing radiotherapy frequently suffer from intestinal mucositis, necessitating discontinuation of treatment. The pathogenesis of the condition involves production of pro-inflammatory cytokines and reactive oxygen metabolites as well as increased apoptosis leading to loss of intestinal structure and function1. To date there is no adequa...

Introduction: For a large number of diseases, inflammation has been shown to be a key factor. This includes also diseases far beyond those classically known, as e.g. functional gastrointestinal diseases and psychic depression. Herbal medicines are an important treatment option in this field. Aim: Over the last years, modern in vitro methods have he...

We earlier showed that STW5, a herbal preparation composed of Iberis amara, Angelicae radix, Matricariae flos, Carvi fructus, Cardui mariae fructus, Melissae folium, Menthae piperitae folium, Chelidonii herba and Liquiritiae radix, and used in Irritable bowel syndrome, reduces proinflammatory signatures in murine models of Gastroesophageal reflux d...

Purpose: Intestinal mucositis is a common adverse effect in patients undergoing radiotherapy and constitutes a treatment-limiting condition. Since no agents are yet known that can adequately guard against ist development, the search continues to find safe and effective measures. The present study was intended to investigate whether the herbal prepa...

Functional dyspepsia (FD) is one of the most common GI-disorders. Because of the chronic relapsing nature and lack of effective treatment options, FD is associated with significantly impaired quality of life and considerable costs. Based on the central role stress seems to be playing in functional GI-diseases, available animal models for FD rely on...

Purpose: STW 5 (marketed as Iberogast(®), Steigerwald Arzneimittelwerk GmbH, Darmstadt, Germany) is a herbal preparation reported to possess anti-inflammatory properties and antioxidant activity. We investigated the effect of STW 5 against intestinal injury induced after whole body exposure to ionizing radiation (IR). Materials and methods: Inte...

Functional dyspepsia (FD) is one of the most common GI-disorders. Because of the chronic relapsing nature & lack of effective treatment options, FD is associated with significantly impaired quality of life and considerable health care costs. Based on the central role stress seems to be playing in functional GI-diseases, available animal models for...

Propolis has been extensively used in folk medicine for the management of a wide spectrum of disorders. In a previous study, we demonstrated the protective effect of the aqueous propolis extract (APE) against the injurious effects of carbon tetrachloride (CCl4) on hepatocytes in vitro. The present investigation was carried out to show whether the h...

Intestinal mucositis is a common side-effect in patients undergoing radiotherapy and poses a severe dose-limiting factor in treatment1. Identification of compounds that prevent radiation-induced mucositis and improve intestinal restitution may offer new therapeutic strategies for maintaining intestinal mucosal integrity in patients undergoing radio...

After oral administration of 100 mg/kg b. w. (235.8 µmol/kg) salicortin to Wistar rats, peak serum concentrations of 1.43 mg/L (13.0 µM) catechol were detected after 0.5 h in addition to salicylic acid by HPLC-DAD after serum processing with β-glucuronidase and sulphatase. Both metabolites could also be detected in the serum of healthy volunteers f...

Pflanzliche Arzneimittel sind eine bewährte Therapieoption beim Reizdarmsyndrom. So ist die Wirksamkeit der pflanzlichen Kombinationspräparate STW 5 und STW 5-II bei dieser Indikation durch klinische Daten belegt [1]. Da subklinische Entzündungszustände möglicherweise an der Entstehung des Reizdarmsyndroms beteiligt sind, stellte sich die Frage, ob...

It has recently been shown in a bioassay guided fractionation of a Willow bark extract (Salicis cortex, Salix spec., Salicaceae) that not the isolated compound salicortin itself but its degradation product catechol was responsible for an anti-inflammatory effect in vitro. To investigate if this in vitro effect has impact on the in vivo situation, a...

Gastroesophageal reflux disease (GERD) is one of the most common GI-diagnosis. Proton pump inhibitors (PPIs) constitute the main treatment, but up to 40% of patients do not achieve adequate symptom control. STW5, a multi-component herbal preparation, was shown to relief concomitant reflux symptoms in patients with functional dyspepsia. Therefore, t...

STW 5 (Iberogast®) is an herbal preparation consisting of nine different extracts namely, Iberis amara, Matricaria recutita, Carum carvi, Melissa officinalis, Mentha piperita, Glycyrrhiza glabra, Silybum marianum, Angelica archangelica and Chelidonium majus. A sister preparation, STW 5-II, has been developed lacking the 3 last components. Both STW...

Gastroesophageal reflux disease (GERD) is one of the most common GI-diagnosis. Proton pump inhibitors (PPIs) present the main treatment, but up to 40% of patients do not achieve adequate symptom control. Therefore the search continues for new therapeutic targets and additional treatment options. STW 5, a multi-component herbal preparation, was show...

Intestinal mucositis is a common adverse effect in cancer patients undergoing radiotherapy and is associated with apoptotic processes. The condition has been simulated in rats by exposing them to acute radiation from a Cesium 137 source. The extent of intestinal injury was dependent on the radiation dose level and histological evidence of apoptosis...

Mitochondrial dysfunction plays a major role in the development of age-related neurodegenerative diseases and recent evidence suggests that food ingredients can improve mitochondrial function. In the current study we investigated the effects of feeding a stabilized rice bran extract (RBE) on mitochondrial function in the brain of guinea pigs. Key c...

Gastroesophageal reflux disease (GERD) was the most common GI-diagnosis (8.9 million visits) in the US in 2012 [1]. Proton pump inhibitors (PPI) present the main treatment, but up to 40 % of patients do not achieve adequate symptom control. Therefore the search continues for new therapeutic targets and additional treatment options. STW5, a multi- c...

Gastroesophageal reflux disease (GERD) was the most common GI-diagnosis (8.9 million visits) in the US in 2012. Although proton pump inhibitors (PPI) represent the treatment of choice, they fail to achieve adequate symptom relief in up to 40% of patients. In the present study, we investigated the modulation of inflammatory markers by STW5 in compa...

An extract was prepared from Egyptian stabilized rice bran and standardized to contain 2% γ-oryzanol in addition to its content of other bioactives, notably tocotrienol and policosanol. The standardized extract was found to have a concentration-dependent effect on insulin release in vitro, which, however, is not mediated by γ-tocotrienol in rice br...

Sodbrennen ist ein häufiges Symptom funktioneller Erkrankungen des oberen Magen-Darm-Trakts, beispielsweise auch der funktionellen Dyspepsie, bei der die Wirksamkeit von STW 5 (Iberogast®) in klinischen Studien belegt ist [1]. Auch im pharmakologischen Modell einer akuten Refluxösophagitis (über 5h) erwies sich STW 5 als wirksam [2]. Daher sollte n...

Iberis amara extract (STW 6, Steigerwald Arzneimittelwerk GmbH, Darmstadt, Germany) has previously been shown to possess good anti-oxidant and anti-inflammatory activity in vitro. The present study deals with testing it in vivo in models of acute and chronic inflammation. The extract showed dose dependent anti-inflammatory activity in the rat paw c...

An herbal preparation, STW 5, used clinically in functional dyspepsia and irritable bowel syndrome, has been shown to possess properties that may render it useful in inflammatory bowel disease (IBD). The present work was conducted to study its effectiveness in a rat model of IBD. An experimental model reflecting ulcerative colitis in man was adopte...

STW 5, a multi-component herbal preparation, was shown to relieve heartburn and concomitant reflux symptoms in patients with functional dyspepsia and to prevent inflammation in an acute model of reflux esophagitis (RE), without affecting the pH of the refluxate. The present study assesses the efficacy of STW 5 in a sub-chronic model of RE, and the...

Psychological factors, especially stress, are known to play an important role in functional gastrointestinal diseases (1, 2). Based on the good correlation between stress and functional dyspepsia (FD), many animal models for FD have been developed where animals are subjected to psychological stress either during the neonatal period or in adulthood....

Proton pump inhibitor (PPI) therapy is the most effective medical treatment for symptom relief in gastro-esophageal reflux disease (GERD). However, up to 40% of patients do not achieve adequate symptom relief, especially those suffering from non-erosive reflux disease (NERD) which does not respond well to PPIs. Therefore, the search continues for o...

To study the effect of aqueous propolis extract (AEP) against indomethacin (Indo)-induced gastric ulcers in irradiated and non-irradiated rats. Animals were irradiated at different radiation dose levels before the induction of ulcers. AEP was injected orally 1 hour before induction of gastric ulcers and the effects compared with those of lansoprazo...

Rice bran is known to contain bioactives which are potentially useful for human health. These include the tocotrienols, policosanol and gamma-oryzanol. Rice bran has been stabilized immediately after collection from the milling stations in order to preserve the integrity of its active constituents. An extract of the stabilized rice bran has been pr...

The 2 kidney, 1-clip (2K, 1C) model of hypertension was used to investigate the potential antihypertensive effect of a standardized leaf extract of Ginkgo biloba (EGb 761). Clipping of the renal artery resulted in gradual elevation of the systolic blood pressure (SBP) reaching a plateau after 4 weeks of surgery. Treatment of hypertensive rats with...

The aim of the present work was to investigate the antihypertensive effect and mechanisms of the action of Hyphaene thebaica, cultivated in Egypt, through examining its effect on the decreased pressure natriuresis, some biochemical changes and invitro effects induced by L-NAME in rats.

The potential value of celecoxib was compared to a standard non-steroidal anti-inflammatory drug (NSAID), diclofenac in the adjuvant-induced arthritis (AIA) model in rats as a model of chronic inflammation under the influence of ionising radiation. Various inflammatory mediators and biochemical parameters were measured in the arthritic rats under t...

Cartilage degradation usually results as a consequence of inflammatory processes in the joints. To study this phenomenon experimentally, adjuvant-induced arthritis (AIA) was used as a model of chronic inflammation under the influence of irradiation. The potential chondroprotective effect of 13% aqueous extract of propolis (AEP) in arthritic rats wa...

A multitarget herbal preparation, STW 5, has been used clinically in different gastro-intestinal disorders including functional dyspepsia and irritable bowel syndrome. Previous studies have shown that it possesses properties that may render it useful in gastro-oesophageal reflux disease (GERD). We performed this study to test this compound in an ac...

The potential value of selective and non-selective COX-2 inhibitors in preventing some of the biochemical changes induced by ionizing radiation was studied in rats exposed to carrageenan-induced paw edema and 6-day-old air pouch models. The animals were exposed to different exposure levels of gamma-radiation, namely either to single doses of 2 and...

Heartburn and acid eructation are symptoms frequently occurring in functional dyspepsia [1]. A number of randomized controlled clinical trials have shown the efficacy of the herbal medicine STW 5 (Iberogast) in functional dyspepsia [2], and especially dyspeptic heartburn [3]. A systematic review, conducted with the aim of identifying potential mech...

The major limiting factor in long-term administration of doxorubicin is the development of cumulative dose-dependent cardiomyopathy and congestive heart failure that limit the use of this drug. The present study was undertaken to find out the chemo protective role of methimazole against doxorubicin-induced cardiotoxicity in experimental animals. In...

A multi-target action is the key to understanding the effect of herbal medicines in a large number of therapeutic fields. To these belongs also heartburn, frequently occurring in dyspeptic patients, and caused by motility disturbances [1]. As a number of randomized controlled clinical trials have shown, the herbal medicine STW 5 (Iberogast®) is act...