The Traditional Japanese Medicine Rikkunshito Promotes Gastric Emptying via the Antagonistic Action of the 5-HT(3) Receptor Pathway in Rats

Intragastric administration of rikkunshito stimulates upper gastrointestinal motility and gastric emptying in conscious dogs

BACKGROUND

Traditional Japanese medicine, known as Kampo medicine, consists of mixtures of several medicinal herbs widely used to treat upper gastrointestinal disorders in Japan. Rikkunshito, one of these medicines, has not been evaluated with respect to its influence on gastrointestinal motor activity. We investigated the effect of rikkunshito on upper gastrointestinal motility and plasma ghrelin concentrations in conscious dogs.

METHODS

Contractile response to intragastric administration of rikkunshito was studied via surgically implanted force transducers. A powdered extract of rikkunshito (1.3, 2.7, and 4.0 g) dissolved in water was administered into the stomachs of normal and vagotomized dogs before feeding and gastric emptying was evaluated. Several inhibitors of gastrointestinal motility (atropine, hexamethonium, and ondansetron) were injected intravenously before intragastric administration of rikkunshito. Plasma acylated ghrelin levels after intragastric administration of rikkunshito were measured.

RESULTS

In a fasting state, intragastric administration of rikkunshito induced phasic contractions in the duodenum and jejunum in normal dogs. Rikkunshito-induced contractions were inhibited by atropine, hexamethonium and ondansetron. In vagotomized dogs, rikkunshito induced phasic contractions, similar to normal dogs. Gastric emptying was accelerated by intragastric administration of rikkunshito in a dose-dependent manner. The plasma acylated ghrelin level 150 min after intragastric administration of 4.0 g of rikkunshito was significantly higher than the control value.

CONCLUSIONS

Intragastric administration of rikkunshito stimulates gastrointestinal contractions in the interdigestive state through cholinergic neurons and 5-HT type 3 receptors. Moreover, rikkunshito increases plasma acylated ghrelin levels. Rikkunshito may alleviate gastrointestinal disorders through its prokinetic effects.

Effect of rikkunshito, a Japanese herbal medicine, on gastrointestinal symptoms and ghrelin levels in gastric cancer patients after gastrectomy

BACKGROUND

Gastric cancer patients who undergo gastrectomy suffer from a post-gastrectomy syndrome that includes weight loss, dumping syndrome, reflux esophagitis, alkaline gastritis, and finally malnutrition. It is important to ameliorate the post-gastrectomy symptoms to restore postoperative quality of life (QoL). The aim of this study was to investigate the effect of rikkunshito, a Japanese herbal medicine, on postoperative symptoms and ghrelin levels in gastric cancer patients after gastrectomy.

METHODS

Twenty-five patients who had undergone gastrectomy received 2.5 g of rikkunshito before every meal for 4 weeks, and a drug withdrawal period was established for the next 4 weeks. Changes in gastrointestinal hormones, including ghrelin, and appetite visual analog scale scores were measured, and QoL was estimated by using the European Organization for Research and Treatment of Cancer core questionnaire QLQ-C30. The Dysfunction After Upper Gastrointestinal Surgery for Cancer (DAUGS) scoring system was used to evaluate gastrointestinal symptoms after gastrectomy.

RESULTS

Sixteen men and nine women (mean age 61.9 years) were enrolled in the study. All patients had either stage I (n = 24) or II (n = 1) disease and had undergone either distal gastrectomy (n = 17) or total gastrectomy (n = 8) by a laparoscopy-assisted approach. The mean ratio of the acyl-/total ghrelin concentration increased significantly after rikkunshito administration (Pre: 7.8 ± 2.1, 4 weeks: 10.5 ± 1.7 %, p = 0.0026). The total DAUGS score, as well as the scores reflecting limited activity due to decreased food consumption, reflux symptoms, dumping symptoms, and nausea and vomiting significantly improved after rikkunshito administration.

CONCLUSIONS

The present study demonstrated a significant attenuation of gastrointestinal symptoms after gastrectomy by treatment with rikkunshito. Rikkunshito is potentially useful to minimize gastrointestinal symptoms after gastrectomy.

Kampo medicines for gastrointestinal tract disorders: a review of basic science and clinical evidence and their future application

Treatment with kampo, the Japanese traditional medicine, is a form of pharmacological therapy that combines modern Western and traditional Asian medical practices. In Japan, various traditional medicines are often combined with Western medicines and prescribed for patients with diseases such as gastroesophageal reflux disease, functional dyspepsia, chronic gastritis, irritable bowel syndrome, and post-operative ileus. Based on numerous past observations, Japanese traditional medicines are thought to be particularly useful in the treatment of medically unexplained physical symptoms such as nausea, abdominal discomfort, and anorexia. However, the detailed mechanism by which they mediate their pharmacological action is yet unknown. In addition, the clinical evidence to support their use is insufficient. This review focuses on the basic evidence of the pharmacological action and the clinical efficacies of kampo medicines accumulated over several past decades. In addition, we introduce both the current novel insights into kampo medicines and the therapeutic approach employed when they are used to treat various disorders of the gastrointestinal tract.

TRPV2 ion channels expressed in inhibitory motor neurons of gastric myenteric plexus contribute to gastric adaptive relaxation and gastric emptying in mice

Gastric adaptive relaxation (GAR) is impaired in ~40% of functional dyspepsia (FD) patients, and nitric oxide (NO) released from inhibitory motor neurons plays an important role in this relaxation. Although the underlying molecular mechanism of GAR is poorly understood, transient receptor potential channel vanilloid 2 (TRPV2) mechano- and chemoreceptors are expressed in mouse intestinal inhibitory motor neurons and are involved in intestinal relaxation. The aim of this study was to evaluate the distribution of TRPV2 in inhibitory motor neurons throughout the mouse gastrointestinal tract and the contribution of TRPV2 to GAR. RT-PCR and immunohistochemical analyses were used to detect TRPV2 mRNA and protein, respectively. Intragastric pressure was determined with an isolated mouse stomach. Gastric emptying (GE) in vivo was determined using a test meal. TRPV2 mRNA was detected throughout the mouse gastrointestinal tract, and TRPV2 immunoreactivity was detected in 84.3% of neuronal nitric oxide synthase-expressing myenteric neurons in the stomach. GAR, which was expressed as the rate of decline of intragastric pressure in response to volume stimuli, was significantly enhanced by the TRPV2 activator probenecid, and the enhancement was inhibited by the TRPV2 inhibitor tranilast. GE was significantly accelerated by TRPV2 agonist applications, and the probenecid-induced enhancement was significantly inhibited by tranilast coapplication. Mechanosensitive TRPV2 was expressed in inhibitory motor neurons in the mouse stomach and contributed to GAR and GE. TRPV2 may be a promising target for FD patients with impaired GAR.

Evolving pharmacological approaches in gastroesophageal reflux disease

INTRODUCTION

Proton pump inhibitors (PPIs) have considerably improved quality of life in patients with gastroesophageal reflux disease (GERD). However, many patients remain symptomatic despite standard PPI therapy.

AREAS COVERED

This review focuses on evolving therapeutic strategies related to the pathophysiological processes of GERD and insufficient response to PPIs. Several clinical trials evaluated new PPI formulations and newer types of acid-suppressive drugs. These studies have evaluated traditional end points in GERD, but have not shown clinical superiority to current PPIs. Novel therapeutic strategies targeting underlying mechanisms of GERD, such as transient lower esophageal sphincter relaxations (TLESRs) and esophageal hypersensitivity, are being developed for add-on therapy to PPIs. Prokinetic drugs may also have some potential in the add-on treatment of GERD with insufficient response to PPIs. Add-on studies are hampered by insufficient information on optimal patient selection and lack of established end points.

EXPERT OPINION

Newer drugs for symptomatic control in GERD have largely focused on improved acid suppression, without evidence of clinical superiority. Drugs targeting esophageal motility and sensitivity to be used as add-onc therapy in PPI insufficient responders have not reached Phase III trials to date, due to difficulties with patient selection, tolerability and end points.

Effects of an Atractylodes lancea rhizome extract and a volatile component β-eudesmol on gastrointestinal motility in mice

AIM OF THE STUDY

The rhizomes of Atractylodes lancea DC (Compositae) are used clinically to treat gastrointestinal symptoms, including functional dyspepsia and gastroparesis, in China and Japan, but their influence and mechanism on gastrointestinal motility are not yet proven in detail.

MATERIALS AND METHODS

This study examined the effects of an Atractylodes lancea extract, and isolated β-eudesmol, on gastric emptying and small intestinal motility in atropine-, dopamine-, and 5-hydroxytryptamine (5-HT)-treated mice.

RESULTS AND CONCLUSIONS

The extract (500 or 1000mg/kg) and β-eudesmol (50 or 100mg/kg), as well as itopride hydrochloride (a dopamine D(2) receptor antagonist, 10 or 50mg/kg), stimulated small intestinal motility in normal mice. They inhibited reductions in gastric emptying and gastrointestinal motility induced by dopamine (1mg/kg, intraperitoneal injection, ip). The extract (1000mg/kg) and β-eudesmol (100mg/kg) inhibited the atropine-induced decrease in small intestinal motility, but not gastric emptying. Furthermore, the extract (500 or 1000mg/kg) and β-eudesmol (25, 50, or 100mg/kg) inhibited reductions in gastric emptying and small intestinal motility caused by 5-HT (4mg/kg, ip) or the 5-HT(3) receptor agonist 1-(3-chlorophenyl) biguanide (0.5mg/kg, ip), but not a 5-HT(2C) receptor agonist. These findings suggest that the extract of Atractylodes lancea and β-eudesmol may stimulate gastric emptying or small intestinal motility by inhibiting the dopamine D(2) receptor and 5-HT(3) receptor.

Rikkunshito improves symptoms in PPI-refractory GERD patients: a prospective, randomized, multicenter trial in Japan

BACKGROUND

To seek a promising therapeutic regimen for proton pump inhibitor (PPI)-refractory patients with gastroesophageal reflux disease (GERD) after the standard PPI treatment, we compared the efficacies of rikkunshito (a Japanese traditional medication) combined with rabeprazole (RPZ) and a double dose of RPZ in a prospective randomized multicenter trial in Japanese PPI-refractory GERD patients.

METHODS

One hundred and four patients with GERD symptoms remaining after 4-week treatment with RPZ (10 mg/day) were randomly assigned to 4 weeks of either combination therapy [rikkunshito (7.5 g/day) with a standard dose of RPZ (10 mg/day)] or a double dose of RPZ (20 mg/day). The primary endpoint was the improvement rate, calculated based on the frequency scale for the symptoms of GERD (FSSG) before and after treatment. Subgroup analysis was also performed with respect to each subject's background factors such as reflux esophagitis (RE)/non-erosive GERD (NERD), age, gender, and body mass index (BMI).

RESULTS

Four-week treatment with rikkunshito combined with RPZ significantly decreased the FSSG score from 17.6 ± 6.5 to 12.0 ± 6.9, similar to the decrease seen on treatment with a double dose of RPZ. Regarding the therapeutic improvement rate, there were also significant effects in both groups. However, in the subgroup analysis based on RE/NERD, the improvement rate of male NERD patients in the rikkunshito group was significantly greater than that of such patients in the other group (P < 0.05). In the rikkunshito group, the treatment was more effective in NERD patients with a low BMI than in those with a high BMI (P < 0.05).

CONCLUSION

Rikkunshito combined with standard-dose RPZ therapy may be a useful new strategy for PPI-refractory GERD patients.

Rikkunshito improves symptoms in PPI-refractory GERD patients: a prospective, randomized, multicenter trial in Japan

BACKGROUND

To seek a promising therapeutic regimen for proton pump inhibitor (PPI)-refractory patients with gastroesophageal reflux disease (GERD) after the standard PPI treatment, we compared the efficacies of rikkunshito (a Japanese traditional medication) combined with rabeprazole (RPZ) and a double dose of RPZ in a prospective randomized multicenter trial in Japanese PPI-refractory GERD patients.

METHODS

One hundred and four patients with GERD symptoms remaining after 4-week treatment with RPZ (10 mg/day) were randomly assigned to 4 weeks of either combination therapy [rikkunshito (7.5 g/day) with a standard dose of RPZ (10 mg/day)] or a double dose of RPZ (20 mg/day). The primary endpoint was the improvement rate, calculated based on the frequency scale for the symptoms of GERD (FSSG) before and after treatment. Subgroup analysis was also performed with respect to each subject's background factors such as reflux esophagitis (RE)/non-erosive GERD (NERD), age, gender, and body mass index (BMI).

RESULTS

Four-week treatment with rikkunshito combined with RPZ significantly decreased the FSSG score from 17.6 ± 6.5 to 12.0 ± 6.9, similar to the decrease seen on treatment with a double dose of RPZ. Regarding the therapeutic improvement rate, there were also significant effects in both groups. However, in the subgroup analysis based on RE/NERD, the improvement rate of male NERD patients in the rikkunshito group was significantly greater than that of such patients in the other group (P < 0.05). In the rikkunshito group, the treatment was more effective in NERD patients with a low BMI than in those with a high BMI (P < 0.05).

CONCLUSION

Rikkunshito combined with standard-dose RPZ therapy may be a useful new strategy for PPI-refractory GERD patients.

Anti-obesity effects of the methanolic extract and chakasaponins from the flower buds of Camellia sinensis in mice

The methanolic extract from the flower buds of Camellia sinensis cultivated in Fujian Province showed inhibitory effects on body weight gain and the weight of visceral fats in high-fat diet-fed mice and/or Tsumura Suzuki Obese Diabetic (TSOD) mice. A suppressive effect of the extract on food intake was suggested to contribute to the anti-obesity effect. The n-butanol (BuOH)-soluble fraction also reduced food intake in normal diet-fed mice. A principal constituent, chakasaponin II, inhibited gastric emptying (GE) as well as food intake. These inhibitory effects were partly reduced by pretreatment with a high dose of capsaicin. The n-BuOH-soluble fraction and chakasaponin II suppressed mRNA levels of neuropeptide Y (NPY), an important regulator of body weight through its effects on food intake and energy expenditure, in the hypothalamus. Furthermore, chakasaponin II enhanced the release of serotonin (5-HT) from the isolated ilea of mice in vitro. These findings suggested that the active saponins suppressed the appetite signals in the hypothalamus through stimulation of the capsaicin-sensitive sensory nerves, probably vagal afferent nerves, or enhancement of 5-HT release from the ilea, leading to reduced food intake and body weight gain.

A New Candidate Supporting Drug, Rikkunshito, for the QOL in Advanced Esophageal Cancer Patients with Chemotherapy Using Docetaxel/5-FU/CDDP

Purpose. Docetaxel/5-FU/CDDP (DFP) therapy is a useful treatment for advanced esophageal cancer. However, adverse reactions such as chemotherapy-induced nausea and vomiting (CINV) interfere often with continuation of the chemotherapy. We investigated the efficacy of rikkunshito (TJ-43) on CINV. Methods. Nineteen patients who were going to undergo DFP therapy were enrolled. They were assigned to the following two groups: a TJ-43-treated group and -nontreated group. The following parameters were compared between the 2 groups: (1) the frequency of symptoms occurred, (2) vomiting, nausea, and anorexia score, and (3) QOL score. Results. The incidence of symptoms was lower in the TJ-43-treated group than that in the control group. The nausea score of the TJ-43-treated group was significantly lower than that of the control group. In the QOL score, the mood score and the ADL score decreased significantly in the control group. Conclusion. We recommend TJ-43 administration in patients undergoing DFP chemotherapy.

Isolation of Bioactive Compounds That Relate to the Anti-Platelet Activity of Cymbopogon ambiguus

Infusions and decoctions of Cymbopogon ambiguus have been used traditionally in Australia for the treatment of headache, chest infections and muscle cramps. The aim of the present study was to screen and identify bioactive compounds from C. ambiguus that could explain this plant's anti-headache activity. A dichloromethane extract of C. ambiguus was identified as having activity in adenosine-diphosphate-induced human platelet aggregation and serotonin-release inhibition bioassays. Subsequent fractionation of this extract led to the isolation of four phenylpropenoids, eugenol, elemicin, eugenol methylether and trans-isoelemicin. While both eugenol and elemicin exhibited dose-dependent inhibition of ADP-induced human platelet serotonin release, only eugenol displayed potent inhibitory activity with an IC₅₀ value of 46.6 μM, in comparison to aspirin, with an IC₅₀ value of 46.1 μM. These findings provide evidence to support the therapeutic efficacy of C. ambiguus in the non-conventional treatment of headache and inflammatory conditions.

The effect of traditional Japanese medicine (Kampo) on gastrointestinal function

Traditional Japanese medicine (Kampo) is used to treat various disorders of the gastrointestinal tract in Japan, where it is fully integrated into the modern healthcare system. Recently, scientific research on herbal medicine in Japan has been reported in English journals. The objective of the current review is to introduce two traditional Japanese medicines and to provide evidenced-based information regarding their use. Daikenchuto, which consists of three different herbs, is the most frequently prescribed traditional Japanese medicine in Japan. Daikenchuto stimulates gastrointestinal motility though a neural reflex involving presynaptic cholinergic and 5-HT3 receptors. Daikenchuto improves postoperative bowel motility and postoperative ileus. Furthermore, it is reported to cause an increase in gastrointestinal hormones (motilin, vasoactive intestinal peptide, and calcitonin gene-related peptide) and intestinal blood flow. Rikkunshito, a traditional Japanese medicine consisting of eight herbs, is thought to stimulate gastrointestinal motility and ghrelin secretion. Rikkunshito is effective for improving the symptoms of functional dyspepsia, gastroesophageal reflux disease, and cisplatin-induced anorexia and vomiting. Traditional Japanese medicine has the potential to be used successfully in the treatment of gastrointestinal disorders. Details regarding the physiological and clinical effects of traditional Japanese medicine must be further examined in order to become more widely accepted in other countries.

Black tea and theaflavins assist healing of indomethacin-induced gastric ulceration in mice by antioxidative action

The healing activities of black tea (BT) and the theaflavins (TF) against the indomethacin-induced stomach ulceration were studied in a mouse model. Indomethacin (18 mg/kg, p.o.) administration induced maximum ulceration in the glandular portion of the gastric mucosa on the 3rd day, accompanied by increased lipid peroxidation and protein oxidation, depletion of thiol-defense and mucin, as well as reduced expressions of cyclooxygenases (COX) and prostaglandin (PG) E synthesis in the gastric tissues, and plasma total antioxidant status of mice. Treatment with BT (40 mg/kg), TF (1 mg/kg), and omeprazole (3 mg/kg) produced similar (74%-76%) ulcer healing, as revealed from the histopathological studies. Treatment with all the above samples reversed the adverse oxidative effects of indomethacin significantly. BT and TF also enhanced the PGE synthesis by augmenting the expressions of COX 1 and 2, but did not modulate acid secretion.

Efficacy of Rikkunshito, a traditional Japanese medicine (Kampo), in treating functional dyspepsia

BACKGROUND

Rikkunshito, a traditional Japanese (Kampo) medicine, is widely prescribed as an oral preparation for the treatment of functional dyspepsia (FD). In our previous study, we reported that extracorporeal ultrasonography (US) is a useful technique for the assessment of the gastric accommodation reflex (AR) and duodenogastric motility. In this study, we examined the effects of Rikkunshito on the gastroduodenal function in patients with FD.

METHODS

Sixteen FD patients (median age, 45 y) underwent US, before and after 14 days of treatment with Rikkunshito (7.5 g b.d.). For assessment of the AR, a cross-sectional area of the proximal stomach was measured after incremental ingestion of a liquid meal up to 400-mL. The expansion rate was used as the parameter to determine the AR. Then, the gastric emptying rate (GER), motility index (MI), and reflux index (RI) were evaluated using previously reported methods.

RESULTS

Although no significant changes were observed in the total score of the Gastrointestinal Symptom Rating Scale (GSRS), the scores of 3 of the 15 symptoms of GSRS decreased significantly after treatment with Rikkunshito. The expansion rate of the proximal stomach was significantly greater after treatment with Rikkunshito than before the treatment. Although the GER and MI increased significantly, no significant differences in the RI were observed after treatment with Rikkunshito.

CONCLUSION

These observations suggested that Rikkunshito may be beneficial for the treatment of FD patients with impaired AR and gastric motility. These results also suggested that Rikkunshito has a therapeutic potential for FD and GERD.