Screening and identification of proteins mediating senna induced gastrointestinal motility enhancement in mouse colon

An experimental model to study the effects of a senna extract on the blood constituent labeling and biodistribution of a radiopharmaceutical in rats

Cassia angustifolia Vahl (senna) is a natural product that contains sennosides, which are active components that affect the intestinal tract and induce diarrhea. Authors have shown that senna produces DNA (deoxyribonucleic acid) lesions in Escherichia coli cultures and can act as an antifungal agent. Natural drugs can alter the labeling of blood constituents with technetium-⁹⁹m (⁹⁹mTc) and can affect the biodistribution of radiopharmaceuticals. In this work, we have evaluated the influence of a senna extract on the radiolabeling of blood constituents and on the biodistribution of the radiopharmaceutical sodium pertechnetate (Na⁹⁹mTcO₄)in Wistar rats. Twelve animals were treated with senna extract for 7 days. Blood samples were withdrawn from the animals and the radiolabeling procedure was carried out. The senna extract did not modify the radiolabeling of the blood constituents. A biodistributional assay was performed by administering Na⁹⁹mTcO₄ and determining its activity in different organs and in blood. The senna extract altered the biodistribution of Na⁹⁹mTcO₄ in the thyroid, liver, pancreas, lungs and blood. These results are associated with properties of the chemical substances present in the aqueous senna extract. Although these assays were performed in animals, our findings suggest that caution should be exercised when nuclear medicine examinations using Na⁹⁹mTcO₄ are conducted in patients who are using senna extract.

Herb-drug pharmacokinetic interactions reviewed

IMPORTANCE OF THE FIELD

the global increase in the popularity of alternative medicines has raised renewed concerns regarding herb-drug interactions. These interactions are especially important for drugs with narrow therapeutic indices and may either be pharmacodynamic or pharmacokinetic in nature.

AREAS COVERED IN THIS REVIEW

pharmacokinetic interactions which may exist between herbs and drugs, and the mechanisms of these interactions with appropriate examples based on primary and secondary data in publications are discussed. The mechanisms covered include those that affect oral drug absorption (e.g., modulation of efflux and uptake transporters, complex formation, gastrointestinal motility and pH) and drug biotransformation (e.g., inhibition or induction of enzymes).

WHAT THE READER WILL GAIN

knowledge on the mechanisms of herb-drug pharmacokinetic interactions supported by an extended list of these types of interactions for quick reference. A critical evaluation of certain herb-drug pharmacokinetic interactions reported in the scientific literature.

TAKE HOME MESSAGE

as the incidence and severity of herb-drug pharmacokinetic interactions increase due to a worldwide rise in the use of herbal preparations, more clinical data regarding herb-drug pharmacokinetic interactions are needed to make informed decisions regarding patient safety.

Herbal remedies are the main etiologic factor in melanosis coli, a case series study

Melanosis coli is a brown to black discoloration of the colon mucosa usually associated with long-term ingestion of laxatives. However, melanosis coli can be found in patients with no history of laxative use. Regular use of herbal remedies could be the major source of anthranoid laxatives in such patients. We designed a prospective case series study to identify the clinical characteristics and etiology of melanosis coli in affected patients. This study took place in Ankara, Turkey, between 08/2005 and 11/2006. Patients with endoscopic diagnosis of melanosis coli were interviewed for demographical data and use of herbal remedies. A total of 380 colonoscopies were performed during this period. Melanosis coli was diagnosed endoscopically in 12 patients (3.17%), 11 of whom were found to have characteristic pigment-laden macrophages in histopathological examination. Herbal remedies were the main etiological factor in the development of melanosis coli in 10 out of 11 patients. Diffuse involvement was found in 2 patients who had a history of long-term use. In 8 patients, melanosis coli was located in the left side of the colon. Although melanosis coli is a harmless discoloration of colonic mucosa resulting from complementary or alternative medicine, we believe that this association with herbals was overlooked or not inquired in patients. Therefore, it should be emphasized that “natural” or “alternative” is not equal to “safe”.

Effects of essential oil from Croton tiglium L. on intestinal transit in mice

AIM OF THE STUDY

Croton tiglium (Croton tiglium L., Euphorbiaceae) is widely used as a herb for treatment of gastrointestinal disturbances. Previous studies established its purgative and inflammational properties. The present study aimed to investigate the effects of Croton tiglium oil (CO) on intestinal transit in mice.

MATERIALS AND METHODS

Gastrointestinal transit in mice and contractile characteristics of isolated intestinal strips from mice were evaluated. Intestinal inflammation was confirmed by histological examination.

RESULTS

Low dose of CO increased the gastrointestinal transit of charcoal and barium meal as well as the production of fecal pellets in mice. In contrast, high dose exerted inhibitory effects. For normal colonic circular strips, both high and low dose of CO inhibited the contractile frequency. Low doses (0-20 microg/ml) of CO enhanced the phasic contractions, while high doses (>40 microg/ml) reduced them. Colonic longitudinal strips in CO-treated mice were less sensitive to electrical field stimulation than those in control mice. The contraction of colonic longitudinal, colonic and jejunal circular strips in CO-treated mice was more sensitive to atropine than that in control mice.

CONCLUSIONS

CO might modulate gastrointestinal motility and induce intestinal inflammation related to immunological milieu and motor activity. Our findings may highlight the ethno-medical uses of Croton tiglium on intestinal disorders.

Assessment of Large Bowel Motility by Cine Magnetic Resonance Imaging Using Two Different Prokinetic Agents

OBJECTIVES

We sought to assess large bowel motility, induced by 2 prokinetic agents, senna tea and erythromycin, using functional cine magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Twelve volunteers underwent functional cine MRI before and after the administration of senna tea or erythromycin. The protocol consisted of 2 sets of repeated measurements using coronal T2-weighted HASTE sequences, adjusted to the course of the colon. For the assessment of large bowel motility, the changes of the luminal diameter were measured at 5 defined locations in the ascending, transverse, and descending colon.

RESULTS

In all examined volunteers after senna tea, the mean number of significant changes in the ascending colon was 8.6 and after erythromycin, 7.2. In the transverse colon, 9.6 diameters changed significantly for senna tea and 7.2 for erythromycin. In the descending colon, 6.6 diameters changed after senna tea and 7.2 after erythromycin.

CONCLUSION

Senna tea and erythromycin proved to induce large bowel motility; senna tea was more effective. Functional cine MRI is a reliable, noninvasive method for the assessment of colonic motility.

Alvimopan: an oral, peripherally acting, mu-opioid receptor antagonist for the treatment of opioid-induced bowel dysfunction--a 21-day treatment-randomized clinical trial

Alvimopan has been shown to reverse the inhibitory effect of opioids on gastrointestinal transit without affecting analgesia. We evaluated oral alvimopan, 0.5 or 1 mg, versus placebo, once daily for 21 days, in 168 patients with opioid-induced bowel dysfunction (OBD) who were receiving chronic opioid therapy (minimum, 1 month) for nonmalignant pain (n = 148) or opioid dependence (n = 20). The primary outcome was the proportion of patients having at least one bowel movement (BM) within 8 hours of study drug on each day during the 21-day treatment period. Averaged over the 21-day treatment period, 54%, 43%, and 29% of patients had a BM within 8 hours after alvimopan 1 mg, 0.5 mg, or placebo, respectively (P < .001). Secondary outcomes of median times to first BM were 3, 7, and 21 hours after initial doses of 1 mg, 0.5 mg, and placebo, respectively (P < .001; 1 mg vs placebo). Weekly BMs and overall patient satisfaction were increased after the 1-mg dose (P < .001 at weeks 1 and 2 vs placebo, and P = .046, respectively). Treatment-emergent adverse events were primarily bowel-related, occurred during the first week of treatment, and were of mild to moderate severity. Alvimopan was generally well tolerated and did not antagonize opioid analgesia. Patients treated with chronic opioid therapy often experience opioid-induced bowel dysfunction as a result of undesirable effects on peripheral opioid receptors located in the gastrointestinal tract. Alvimopan, a novel peripheral opioid mu-receptor antagonist, has demonstrated significant efficacy for the management of opioid-induced bowel dysfunction without compromise of centrally mediated opioid-induced analgesia.

Alterations of gastrin, somatostatin, G and D cells in rat gastric ulcer

AIM: To investigate the alterations of gastrin secretion of G cells, somatostatin secretion of D cells and the change of G (D) cells in rat gastric ulcer.

METHODS: An acetic-acid-induced rat gastric ulcer model was established. The histological structure of rat antral mucosa and the ultrastructure of mucosal cells were observed generally, through microscope and through electron microscope. The content of gastrin or somatostatin in serum or in antral tissue was measured via radioimmunoassay. The shape, number, size of G (D) cells, and the ratio of number and size of G/D cells were viewed and analyzed with immunohistochemical technique and image analysis system. G (D) cells and the secretive gastrin (somatostatin) granules in G (D) cells were observed through immunoel-ectron microscope and analyzed in image analysis system.

RESULTS: G (D) cells and the secretive gastrin (somatostatin) granules in G (D) cells were observed through immunoelectron microscope successfully. In gastric ulcer rat the secretive gastrin in G cells increased, the secretive somatostatin in D cells declined, the number of G cells increases and the size of G cells declined; both the number and the size of D cells declined, both the ratio of the number and size of G/D cells increased, both the content of gastrin in serum and in antral tissue increased, and both the content of somatostatin in serum and in antral tissue declined.

CONCLUSION: The rat gastric ulcer induces the changes of G cells and D cells, secretive gastrin in G cells and secretive somatostatin in D cells, as well as the contents of gastrin and somatostatin.

Effects of neurotrophins on gastrointestinal myoelectric activities of rats

AIM: To observe the effects of mouse nerve growth factor (NGF), rat recombinant brain derived neurotrophic factor (rm-BDNF) and recombinant human neurotrophin-3 (rh-NT-3) on the gastrointestinal motility and the migrating myoelectric complex (MMC) in rat.

METHODS: A randomized, double-blinded, placebo-controlled experiment was performed. 5-7 days after we chronically implanted four or five bipolar silver electrodes on the stomach, duodenum, jejunum and colon, 21 experimental rats were coded and divided into 3 groups and injected NGF, rm-BDNF, rh-NT-3 or placebo respectively via tail vein at a dose of 20 μg·kg^{- 1}. The gastrointestinal myoelectrical activity was recorded 2 hours before and after the test substance infusions in these consciously fasting rats.

RESULTS: The neurotrophins-induced pattern of activity was characterized by enhanced spiking activity of different amplitudes at all recording sites, especially in the colon. In the gastric antrum and intestine, only rh-NT-3 had increased effects on the demographic characteristics of electrical activities (P < 0.05), but did not affect the intervals of MMCs. In the colon, all the three kinds of neurotrophins could significantly increase the frequency, amplitude and duration levels of spike bursts, and also rh-NT-3 could prolong the intervals of MMC in the transverse colon (25 ± 11 min vs 19 ± 6 min, P < 0.05). In the distal colon rh-NT-3 could evoke phase III-like activity and disrupt the MMC pattern, which was replaced by a continuously long spike bursts (LSB) and irregular spike activity (ISA) for 48 ± 6 min.

CONCLUSION: Exogenous neurotrophic factors can stimulate gut myoelectric activities in rats.

Effects of Chinese herb complex Jianpiwan and Baohewan on gastrointestinal motility in rats

AIM: To investigate the effects of Jianpiwan and Baohewan on gastrointestinal motility in rats.

METHODS: Using dextran blue 2000 as a gastrointestinal internal marker its relative remaining rate in stomach and its pushing ratio of the bowel, we observed the effects of Jianpiwan and Baohewan on the emptying of stomach and the driving of bowel in normal and splenic asthenic rats.

RESULTS: Baohewan and Jianpiwan had evidently promoting effect on emptying of stomach in normal and splenic asthenic rats 0.029±0.033 vs 0.059±0.035; 0.018±0.010 vs 0.059±0.035; 0.036±0.028 vs 0.089±0.042; 0.029±0.026 vs 0.089±0.042 (P < 0.05). Baohewan had better effect than Jianpiwan on the driving of bowel in normal rats 58.8±11.3 vs 51.6±9.7 (P < 0.05). For splenic asthenic rats whose vermiculation was reinforced, Baohewan still had promoting effect 63.5±6.1 vs 54.1±12.3 (P < 0.05) and Jianpiwan can slow the vermiculation and help it recover to normal leves 43.0±7.1 vs 54.1±12.3 (P < 0.05).

CONCLUSION: Baohewan and Jianpiwan have promoting and adjusting effects on gastrointestinal motility in rats.