Anti-diarrhoeal effects of seirogan in the rat small intestine and colon examined in vitro

Antibacterial and antidiarrheal activities of plant products against enterotoxinogenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) produces two types of enterotoxins: heat-labile (LT) and heat-stable (STa and STb). These molecules are involved in the induction of secretory diarrhea in animals including humans. This condition is currently treated using a fluid replacement therapy and antibiotics. This treatment is often not available to people in developing countries, and several die from the condition provoke by ETEC. Over the years, plants and plant extracts have been use as traditional medicine to treat various gastrointestinal ailments including diarrhea. Many of these plant products have been claimed to be active against diarrhea, however few have been extensively studied. The main objective of this review was to gather the scattered information on the antidiarrheal activities reported for various plant products on ETEC. This includes two major effects: (1) The inhibitory effect on bacterial growth or viability and (2) The interference with ETEC enterotoxins activity upon the intestinal epithelium. We will focus on plant products and extracts for which we have major indications of their biological activity against ETEC and their enterotoxins. Because Vibrio cholerae toxin (CT) is structurally, antigenically and mechanistically related to LT, it will also be discussed in this review.

Effect of products derived from hydrolysis of wheat and flaxseed non starch polysaccharides by carbohydrase enzymes on net absorption in enterotoxigenic Escherichia coli (K88) challenged piglet jejunal segments

Enterotoxigenic Escherichia coli (ETEC) infection results in fluid and electrolyte losses in the small intestine. We investigated the effect of non-starch polysaccharides (NSP) hydrolysis products of wheat middlings (WM) and flaxseed (FS) on net absorption of fluid and solutes during ETEC challenge. Products were generated by incubating WM and FS with a blend of carbohydrase enzymes to produce 2 products: 80% ethanol-soluble (ES) and 80% ethanol-insoluble (EI) which were studied in 2 experiments in which 2 factors were investigated: products (EI vs. ES) and time of ETEC challenge (before vs. after perfusion). Pairs of small-intestine segments, one non-challenged and the other ETEC-challenged were perfused with products for 7.5 h. ETEC reduced fluid absorption by more than 380 microL/cm(2) in saline (control) perfused segments, whereas this reduction was significantly (P < 0.05) less for the WM and FS products. Interaction (P > 0.05) between product and time of challenge was not observed. For WM, products effects on ETEC-challenged segments were such that perfusion of ES resulted in higher total solute (measured as osmolality) absorption than EI (138 vs. 103 microOsmol/cm(2)). In conclusion, hydrolysis products from WM and FS were beneficial in maintaining fluid balance during ETEC challenge, suggesting potential in controlling ETEC induced diarrhea in piglets.

Nonstarch polysaccharide hydrolysis products of soybean and canola meal protect against enterotoxigenic Escherichia coli in piglets

Infectious diarrhea is a major problem in both children and piglets. Enterotoxigenic Escherichia coli (ETEC) infection results in fluid and electrolyte losses in the small intestine. We investigated the effect of nonstarch polysaccharide (NSP) hydrolysis products of soybean meal (SBM) and canola meal (CM) on net absorption of fluid and solutes during ETEC infection. Products were generated by incubating SBM and CM with a blend of carbohydrase enzymes. Following incubation, slurries were centrifuged and the supernatants mixed with absolute ethanol to produce 2 product types: 80% ethanol-soluble (ES) and 80% ethanol-insoluble (EI). Products from SBM and CM were studied in 2 independent experiments in which 2 factors were investigated: product type (EI vs. ES) and time of ETEC infection (before vs. after perfusion). Pairs of small intestine segments, one noninfected and the other ETEC infected, were perfused simultaneously with different products for 7.5 h. Net absorption of fluid and solutes were determined. In both experiments, ETEC-infected segments perfused with saline control had lower (P < or = 0.05) net fluid and solute absorption compared with SBM and CM products. The interaction (P < or = 0.05) between product type and time of infection on fluid absorption was only evident for SBM, in which case perfusing ES products before infection resulted in higher fluid absorption (735 +/- 22 microL/cm2) compared with ETEC infection before perfusion (428 +/- 34 microL/cm2). In conclusion, NSP hydrolysis products of SBM and CM, particularly ES from SBM, were beneficial in maintaining fluid balance during ETEC infection, suggesting potential for controlling ETEC-induced diarrhea in piglets.

A high molecular weight soluble fraction of tempeh protects against fluid losses in Escherichia coli-infected piglet small intestine

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhoea in children and piglets. Infection of ETEC results in fluid secretion and electrolyte losses in the small intestine. In this study the effects of tempeh, a traditional fungal fermented soyabean product, on fluid losses induced by ETEC infection in piglets was investigated. Pairs of ETEC-infected and non-infected small intestinal segments of piglets were perfused simultaneously for 8 h with pre-digested tempeh, its supernatant and saline as an internal control. In saline perfused segments, ETEC infection reduced net fluid absorption by more than 500 μl/cm2, whereas this reduction was significantly less for pre-digested tempeh and its supernatant (75 and 282 μl/cm2, respectively). The supernatant of pre-digested tempeh was also compared with its permeate and retentate fractions. These fractions were created by ultra-filtration and contained respectively low and high molecular weight (>5 kDa) compounds. Again ETEC infection caused a significant reduction of net fluid absorption when perfused with saline (386 μl/cm2) and also with the permeate fraction (300 μl/cm2), but much less with the supernatant and the retentate fraction (125 and 140 μl/cm2, respectively). The reduction in net fluid absorption upon ETEC infection when perfused with supernatant of either undigested or pre-digested tempeh was not different. Therefore from this study it can be concluded that a high molecular weight soluble fraction of tempeh is able to protect against fluid losses induced by ETEC, suggesting that this could play a potential role in controlling ETEC-induced diarrhoea.

Stress-induced breakdown of intestinal barrier function in the rat: reversal by wood creosote

Our previous studies demonstrated that wood creosote (Seirogan) inhibits intestinal secretion and normalizes the transport of electrolytes and water in rats subjected to restraint stress. The goal of the present study was to examine whether wood creosote has a protective effect against stress-induced breakdown of intestinal barrier function. F-344 rats were subjected to 90-min water avoidance stress (WAS) with wood creosote (30 mg/kg) or vehicle administered intragastrically 30 min prior to WAS. Sham stressed rats received wood creosote or vehicle treatment but did not experience the WAS. All rats were euthanized at the end of the WAS or sham-stress and the jejunum and colon were isolated. Epithelial transport was studied in modified Ussing chambers. Spontaneous secretion was assessed by electrophysiological measurement of the short circuit current (I(sc)) while electrical conductance (G) was calculated from the potential difference (PD) and I(sc) using Ohm's law. Intestinal permeability was defined by the mucosal-to-serosal flux of horseradish peroxidase (HRP). WAS significantly elevated basal I(sc) and G and increased epithelial permeability to HRP in the jejunum but not in the colon. Wood creosote resulted in a significant reduction of the stress-induced increase in I(sc), G and the mucosal-to-serosal flux of HRP compared to the vehicle-treated group. Wood creosote caused no significant effects in sham-stressed rats. The results suggest that oral administration of wood creosote may prevent stress-induced diarrhea by preventing aversive effects on small intestinal secretion and barrier function.

Wood creosote inhibits calcium mobilization in Guinea pig colonic smooth muscle

Wood creosote, a mixture of simple phenolic compounds, has long been used as an herbal antidiarrheal medicine. Previous studies have shown that wood creosote has antimotility activity on the gastrointestinal (GI) tract, although its mechanism of action is not completely understood. The in vitro efficacy of wood creosote on calcium mobilization in guinea pig colonic smooth muscle was evaluated using a digital video camera system mounted on an inverted fluorescence microscope. The effects of wood creosote on spontaneous periodic increases in the free cytosolic calcium concentration ([Ca(2+)](i)), acetylcholine (ACh)-enhanced periodic increases in [Ca(2+)](i), and tetrodotoxin- or nifedipine-resistant spontaneous periodic increases in [Ca(2+)](i) were evaluated. Wood creosote decreased the amplitude of spontaneous (IC(50)=21 microg/ml) and ACh-enhanced (IC(50)=40 microg/ml) periodic increases in [Ca(2+)](i) in guinea pig colonic smooth muscle. Wood creosote also decreased the amplitude of both tetrodotoxin- and nifedipine-resistant spontaneous periodic increases in [Ca(2+)](i). These results suggest that antimotility activity through inhibition of Ca(2+) mobilization in the GI tract is at least partially responsible for the antidiarrheal activity of wood creosote. Wood creosote may exert its antimotility effect, at least in part, on network regions of interstitial cells of Cajal, which act as pacemaker cells and mediators of neurotransmission in the GI tract.

Wood Creosote, the Principal Active Ingredient of Seirogan, an Herbal Antidiarrheal Medicine: A Single-Dose, Dose-Escalation Safety and Pharmacokinetic Study

STUDY OBJECTIVE

To assess the safety, tolerability and pharmacokinetics of escalating single doses of wood creosote, an herbal antidiarrheal and antispasmodic agent.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

Clinical research center.

SUBJECTS

Forty (32 men, 8 women) healthy volunteers aged 19-42 years.

INTERVENTION

By random assignment, 22 men and 8 women received escalating single doses of wood creosote (45, 90, 135, 180, and 225 mg) and 10 men received placebo (for each of the five dose levels, 6 subjects received active substance and 2 subjects received placebo).

MEASUREMENTS AND MAIN RESULTS

Vital signs, laboratory tests, and electrocardiograms were assessed; no dose-related or clinically significant changes were noted. Serial blood samples were obtained to determine the pharmacokinetics of four major active components of wood creosote: total (conjugated plus free) guaiacol, creosol, o-cresol, and 4-ethylguaiacol. The most common adverse events were mild headache and dizziness, with no dose-related trends being apparent. Area under the concentration-time curve from time zero to infinity increased in a dose-proportional manner for total guaiacol, creosol, and o-cresol and was not assessed for total 4-ethylguaiacol owing to lack of data at the low dose level. No apparent differences by sex were noted for any of the four active components. All four components were rapidly eliminated.

CONCLUSION

Single oral doses of wood creosote up to 225 mg were safe and well tolerated in healthy men and women. Also, the doses of wood creosote were rapidly absorbed, conjugated, and eliminated. Such a rapid onset and short duration of action would appear desirable in the treatment of acute nonspecific diarrhea.

Multiple-dose escalation, safety, and tolerability study of wood creosote, the principal active ingredient of seirogan, an herbal antidiarrheal medication, in healthy subjects

Seirogan, an herbal medicine containing wood creosote (CAS 8021-39-4), a mixture of simple phenolic compounds, has been marketed for the past century in Asia for the treatment of acute diarrhea and associated symptoms, such as abdominal discomfort and cramping. The present study was designed to assess the safety and tolerability of an anticipated acute antidiarrheal dosing regimen. Sixty healthy males were randomized into five groups of 12 subjects each (9 wood creosote; 3 placebo) to receive 45-, 90-, 135-, 180-, and 225-mg tablets every 2 hours for five doses. Serial sitting and standing vital signs, ECG rhythm strips, and continuous telemetry monitoring were obtained predose and for 24 hours after the first dose. Clinical laboratory tests and 12-lead resting ECGs were obtained predose and 24 hours postdose. Of the subjects, 27% (12/45) receiving wood creosote and 27% (4/15) receiving placebo reported adverse events. The most common adverse events were altered taste and somnolence, reported more often with 180- and 225-mg doses. Wood creosote had no clinically significant effects on vital signs, ECG intervals or interpretations, or clinical laboratory tests. No clinically significant or serious dysrhythmias were reported on continuous telemetry monitoring. It was concluded that oral doses of wood creosote 45 to 225 mg every 2 hours for up to five doses were safe and well tolerated in 45 healthy subjects. Wood creosote doses ranging from 45 to 135 mg per dose, which are commonly administered antidiarrheal doses in Asia, were associated with minimal side effects.

Effects of seirogan (wood creosote) on propulsive colonic motility and stool characteristics in ambulatory mini-pigs

Our goal was to determine whether Seirogan, an herbal medicine used as an antidiarrheal agent, modifies colonic function, including motility. Experiments were performed on four female Yucatan mini-pigs with established permanent cecal fistulas providing direct access to the colon. Long-term recordings of proximal colonic motility were accomplished by a solid-state probe (six pressure ports 10 cm apart), and a motility index was calculated. Stool viscosity was also measured. The laxative bisacodyl (15 mg/kg) was used to induce colonic motility (increase in motility index) and stool softening, prior to investigating the effect of Seirogan (2-15 mg/kg per os twice a day) or a vehicle control. Seirogan (15 mg/kg), but not the placebo, reversed the bisacodyl-induced stool softening and restored the motility index to normal values by reducing the number of propagating contractions. Taken together the results suggest that inhibition of proximal colonic motility by Seirogan may contribute to its antidiarrheal action.

In vitro effects of wood creosote on enterotoxin-induced secretion measured electrophysiologically in the rat jejunum and colon

Secretory diarrhea occurs when the balance between intestinal absorption and secretion is disturbed by excessive secretion caused by enterotoxins produced by the pathogen. Wood creosote has long been used as a traditional antidiarrheal remedy. The goal of our study was to extend our knowledge about the antisecretory action of wood creosote against Escherichia coli enterotoxin-induced secretion in the small intestine and colon. Experiments were performed in mucosal sheets of rat jejunum and colon which were stripped of the external muscle layers to eliminate interactions with smooth muscle activity and local blood flow. Mucosal sheets were placed in modified Ussing chambers and hypersecretory conditions were induced by heat-labile (LT) or heat-stable (STa) E. coli enterotoxins added cumulatively (0.01-10 microg/ml) to the mucosal bathing solution. Intestinal secretion was monitored electrophysiologically as transmucosal short circuit current (Isc). LT induced a concentration-dependent increase in Isc in the rat jejunum, with no effect in the colon. In contrast, STa induced a significant increase in colonic Isc, without causing any change in Isc across the jejunum. In separate experiments the effects of increasing concentrations of wood creosote (0.1-50 microg/ml), added to the mucosal or serosal bathing solution, were examined against the secretory responses induced by LT or STa. In the small intestine the antisecretory activity of wood creosote against LT-induced secretion was more potent following serosal application, whereas in the colon wood creosote inhibited STa-induced secretion with equal potency following either serosal or mucosal addition. In summary, our findings demonstrate that wood creosote possesses antidiarrheal activity suppressing E. coli enterotoxin-induced secretion in both the small intestine and colon.

Inhibition of small intestinal secretion by cannabinoids is CB1 receptor-mediated in rats

We tested the hypothesis that cannabinoids, acting via a neuronal mechanism of action decrease small intestinal secretion. In vitro electrical stimulation induced ileal secretion in rats, that was attenuated by a cannabinoid receptor agonist, WIN 55212-2, (mesylate(R)-(+)-[2, 3-dihydro-5-methyl-3-[4-morpholino)methyl]pyrrolo-[1,2,3-de]-1, 4-benzoxazin-6-yl](1-naphthyl)methanone) but not its optical isomer WIN 55212-3. The inhibition of secretion induced by WIN 55212-2 was reversed by SR141716A (N-(piperidin-1-yl)-5-(4-chlorophenyl)-1(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride), a cannabinoid CB1 receptor antagonist. An ileal secretory response stimulated by acetylcholine was unaffected by WIN 55212-2. These findings show that cannabinoids inhibit neurally mediated secretion via cannabinoid CB1 receptors. Thus, cannabinoids may have therapeutic potential for diarrhea unresponsive to available therapies.