Abstract
Plant-sourced formulations such as Iberogast and the traditional Chinese medicine formulation, Cmed, purportedly possess anti-inflammatory and radical scavenging properties. We investigated Iberogast and Cmed, independently, for their potential to decrease the severity of the large bowel inflammatory disorder, ulcerative colitis. Sprague Dawley rats (n = 8/group) received daily 1 mL gavages (days 0-13) of water, Iberogast (100 μL/200 μL), or Cmed (10 mg/20 mg). Rats ingested 2% dextran sulfate sodium or water ad libitum for 7 days commencing on day 5. Dextran sulfate sodium administration increased disease activity index scores from days 6 to 12, compared with water controls (P < .05). On day 10, 200 μL Iberogast decreased disease activity index scores in colitic rats compared with colitic controls (P < .05). Neither Iberogast nor Cmed achieved statistical significance for daily metabolic parameters or colonic crypt depth. The therapeutic effects of Iberogast and Cmed were minimal in the colitis setting. Further studies of plant extracts are required investigating greater concentrations and alternative delivery systems.
Keywords
Introduction
Inflammatory bowel disease is the term for a group of inflammatory diseases affecting the gastrointestinal tract. While its etiology is unclear, it is believed that genetically susceptible hosts are impacted by environmental triggers and antigens, thereby stimulating an abnormal immune response. 1 Ulcerative colitis is a variant of inflammatory bowel disease that primarily affects the large intestine. 2 Ulcerative colitis is characterized by acute and chronic inflammation of the mucosa, resulting in ulceration of the colon, bloody diarrhea, rectal bleeding, abdominal pain, and weight loss. 3,4 Histologically, an influx of polymorphonuclear leukocytes and mononuclear cells is usually present accompanied by red blood cell extravasation, mucin discharge, crypt abscesses, and a disruption of crypt architecture. 3 Common drug therapies such as aminosalicylates, corticosteroids, and immunomodulators are used for maintenance and remission of disease; however, when drug therapies are exhausted, invasive surgery may be required to resect the colon. 4 Currently, there are no truly effective treatment modalities for inflammatory bowel disease and alternative preventative or treatment strategies are being sought.
Oral administration of dextran sulfate sodium to rodents induces colitis with similar clinical and histopathological features to human ulcerative colitis. 5 The dextran sulfate sodium–colitis model has been used widely to test the potential effectiveness of newly developed ulcerative colitis treatments. Dextran sulfate sodium is a synthetic polysaccharide comprising sulfated anhydroglucose units. Its mechanism of action constitutes direct mucosal cytotoxicity; disruption of the interaction between intestinal lymphocytes, epithelial cells, and the extracellular matrix; changing expression of β7 integrin receptors; and changes in the intestinal microflora. 5–8
The use of natural remedies has increased in inflammatory bowel disease patients, despite reported effects being largely anecdotal or historical. 9 Indeed, up to 50% of inflammatory bowel disease patients have been reported to use some form of alternative medicine to alleviate gastrointestinal complaints. 10 Recently, protection of the stomach by naturally occurring components in plants has been described—attributed to their anti-inflammatory and antioxidant properties. 11 These components include flavonoids such as Garcinia cambogia, a plant extract native to Southeast Asia, and Devil’s Claw (Harpagophytum procumbens) found in southern Africa. 12,13 In this context, a multiherbal extract known as STW 5, marketed under the name Iberogast, has been reported to possess antioxidant and anti-inflammatory properties. 14
Iberogast is a plant-based liquid formulation comprising 9 different herbal extracts including 15% Iberus amara (bitter candy tuft), 10% Angelica archangelica (angelica root), 20% Matricaria recutita (chamomile), 10% Carum carvi (caraway), 10% Silybum marianum (St Mary’s thistle), 10% Melissa officinalis (lemon balm leaf), 5% Mentha piperita (peppermint leaf), 10% Chelidonium majus (celadine herb), and 10% Glycyrrhiza glabra (liquorice root). Iberogast has primarily been used in the treatment of functional dyspepsia and irritable bowel syndrome, 15,16 and it has recently demonstrated promise in the treatment of chemotherapy-induced mucositis. 17 Moreover, Iberogast has a favorable safety profile with no significant toxicological or hepatotoxic data for 10-fold or higher concentrations. 18
Traditional Chinese medicine is a decoction of various herbs that have provided medicinal aid for centuries. Traditional Chinese medicine is gaining momentum as a potential treatment strategy for ulcerative colitis, given the deficiencies in traditional Western medicines. 19 For example, maintenance of healthy digestive function has been described in Taiwanese and German inflammatory bowel disease sufferers. 20,21 However, there is currently a dearth of scientific evidence to attest the efficacy of these herbal medicines. Recently, certain traditional Chinese medicine herbs have undergone investigations for their potential therapeutic properties in the context of ulcerative colitis. Astragalus root (Astragalus membranaceus) and Barley (Hordeum vulgare) have demonstrated attenuation of diarrhea, reduction of colonic mucosal damage, and the induction of remission in colitic rats. 22,23 Lycium fruit (Lycium barbarum) has also been shown to reduce levels of nitric oxide in experimentally induced diabetes. 24
The traditional Chinese medicine formulation of ChinaMed CM102 + CM132 (Cmed) is of current interest, as 2 of the active components have independently demonstrated an alleviation of colitic symptoms. 23,24 Cmed is a combination of herbal remedies CM102 and CM132. The herbal formula CM102 comprises various herbs such as Astragalus root, which is used principally to relieve digestion problems. Barley and Lycium fruit are 2 known components in the CM132 formulation, which is recommended for the reduction of nervous tension in humans.
The current study compared the potential for Iberogast and ChinaMed CM102 + CM132 to independently ameliorate features of dextran sulfate sodium–induced ulcerative colitis in rats.
Materials and Methods
General Experimental Procedures
All animal experiments were performed with ethical approval from the animal ethics committees of the Women’s and Children’s Hospital and The University of Adelaide, in compliance with The Australian Code of Practice for the Care and Use of Animals for Scientific Purposes. Male Sprague Dawley rats (135-150 g) were housed individually in metabolism cages (Tecniplast, Exton, PA) throughout acclimatization (2 days prior to experimentation) and the experimental period with ad libitum access to an 18% casein-based diet and water.
The dose of the combined Cmed preparation (ChinaMed, Sun Herbal Pty Ltd, New South Wales, Australia) was prepared for a human equivalent (Cmed1, 10 mg/mL; Cmed2, 20 mg/mL) in distilled water. Iberogast (IBE, Flordis Herbal Medicines, Crow’s Nest, New South Wales, Australia) was prepared at 100 μL/mL (Ibe1) or 200 μL/mL (Ibe2).
Rats were randomly assigned to 10 groups (n = 8): Groups 1-5 ingested water ad libitum and were gavaged daily for days 0 to 12 with 1 mL of either water (Group 1), Cmed1 (Group 2), Cmed2 (Group 3), Ibe1 (Group 4), or Ibe2 (Group 5). Between days 5 and 13, drinking water was substituted for a 2% dextran sulfate sodium drinking solution in Groups 6 to 10 (ICN Biomedicals, Inc, Aurora, OH) to induce experimental colitis. The dextran sulfate sodium–treated rats were gavaged with water (Group 6), Cmed1 (Group 7), Cmed2 (Group 8), Ibe1 (Group 9), or Ibe2 (Group 10).
Disease Activity Index and Daily Metabolic Data
Body weight, food and water intake, and fecal and urine output were monitored and measured daily. The severity of colitis was assessed daily, using a disease activity index, which scored body weight loss, stool consistency, rectal bleeding, and overall general condition of the animal, increasing in severity on a scale of 0 to 3 for each parameter. These scores were totaled to achieve an overall maximum disease activity index score of 12.
13 C-Sucrose Breath Test
The
13
C-sucrose breath test provides a noninvasive measurement of small intestinal function.
25
The
13
C-sucrose breath test involves measuring
13
CO2 levels in expired breath as an indirect measure of small intestinal brush-border activity. The breath test was performed on days 0, 5, and 13. The
13
C-sucrose breath test was performed at approximately 9
Tissue Collection
On day 13, rats were sacrificed by CO2 asphyxiation followed by cervical dislocation. Following sacrifice, weights and lengths of all visceral organs were recorded and discarded. Two-centimeter segments of colon were removed and placed in 10% buffered formalin for histological analyses.
Histological Analysis
Proximal and distal colonic samples were routinely processed, embedded in paraffin wax, sectioned (4 μm), and stained with hemotoxylin and eosin. Histological analysis was performed using a light microscope (Nikon Corporation, Tokyo, Japan) with digital camera (Progres C5, Jenoptik, Germany) and Image Pro Plus Software Package Version 5.1 (Media Cybernetics, Rockville, MD). Measurements of crypt depth were determined from 40 crypts over 4 cross sections for both proximal and distal colonic samples per rat and a mean value was then obtained. 26,27
Statistical Analysis
Bodyweight data prior to (days 1-4) and during (days 6-12) dextran sulfate sodium consumption comparisons were performed using a 2-way ANOVA test with Tukey’s post hoc test and expressed as mean ± standard error of the mean. Disease activity index data were compared using a Kruskal–Wallis 1-way ANOVA based on ranks test with pairwise multiple comparison procedures (Dunn’s method) and expressed as median [range]. Data from all other analyses were compared using a 1-way ANOVA with a Tukey’s post hoc test and expressed as mean ± standard error of the mean. Statistical comparisons were performed using SPSS version 16.0 for Windows (SPSS Inc, Chicago, IL). For all analyses, P < .05 was considered significant.
Results
Daily Metabolic Data
Total food and fluid intake and urine and fecal output of all groups remained unchanged by ingestion of traditional Chinese medicine or Iberogast during each experimental period, prior to (days 1-4; Figure 1) and during (days 6-12; Figure 2) dextran sulfate sodium consumption (P > .05). Body weight was determined as a mean percentage change from the beginning of each period, prior to (days 1-4) and during (days 6-12) dextran sulfate sodium consumption. Bodyweight remained unchanged for all treatment groups prior to and during dextran sulfate sodium consumption. Furthermore, there were no significant differences in body weight change between any groups during either period (Table 1).

Total food (A) and fluid (B) intake and fecal (C) and urine (D) output, prior to dextran sulfate sodium consumption (days 1-4) in rats (n = 8/group). Day 0 data was excluded due to rats fasting. Data are expressed as mean (g or mL) ± standard error of the mean.

Total food (A) and fluid (B) intake and fecal (C) and urine (D) output, during dextran sulfate sodium consumption (days 6-12) in rats (n = 8/group). Days 5 and 13 data were excluded due to rats fasting. Data are expressed as mean (g or mL) ± standard error of the mean.
Percentage Change of Bodyweight in Rats.a
Abbreviations: DSS, dextran sulfate sodium; SEM, standard error of the mean.
a Percentage change of bodyweight in rats (n = 8/group) from the beginning of periods before DSS (days 1-4) and during DSS consumption (days 6-12). Days 0, 5, and 13 data were excluded due to rats fasting. Data are expressed as mean (%) ± SEM.
Disease Activity Index
An increase in disease activity index, a quantitative measurement of the progression and resolution of disease, is a common feature of the dextran sulfate sodium–induced model of colitis. Disease activity index score was significantly greater in colitic rats on days 6 to 12 compared to healthy controls (P < .01). On day 10, Iberogast (200 μL/mL) administered to dextran sulfate sodium–treated rats resulted in a significantly lower disease activity index score compared to dextran sulfate sodium–treated control rats (P < .05). Otherwise, neither the lower dose of Iberogast nor Cmed significantly affected colitic disease activity (Table 2).
Disease Activity Index.a
Abbreviations: DAI, disease activity index; DSS, dextran sulfate sodium.
a DAI between days 5 and 12 during the development of DSS-induced colitis in rats (n = 8/group). Data are expressed as median DAI score [range].
*P < .05 compared with water + water. ^P < .05 compared with DSS + water.
13 C-Sucrose Breath Test
Activity of the small intestinal brush border enzyme, sucrase, provides an indication of the functional integrity of the small intestine. On days 5 and 13, the absorptive capacity of the small intestine was not significantly affected by dextran sulfate sodium, Cmed, or Iberogast, as indicated by the percentage cumulative dose at 90 minutes (P > .05; Figure 3). Furthermore, the percentage cumulative dose at 90 minutes coefficient of variation of healthy rats on day 0 was 32%.

Overall small intestinal functional health status in rats assessed using the 13 C-sucrose breath test immediately prior to dextran sulfate sodium (DSS) consumption (day 5) and on day of sacrifice (day 13) (n = 8/group). Data are expressed as mean (% cumulative dose of 13 C at 90 minutes; %CD90) ± standard error of the mean.
Visceral and Gastrointestinal Organ Weights and Lengths
Dextran sulfate sodium consumption, Cmed, or Iberogast did not significantly affect visceral and gastrointestinal organ weights (expressed as a percentage of body weight; P > .05; Tables 3 and 4). Although dextran sulfate sodium decreased mean colon length by 16% (12.24 ± 0.63 cm) compared to its water control group (14.84 ± 0.53 cm), this just failed to attain statistical significance (Table 5). Dextran sulfate sodium administration did not affect duodenum or jejunum-ileum length, and there were no additional effects of either Cmed or Iberogast on these parameters (Table 5).
Visceral Organ Weights.a
Abbreviations: DSS, dextran sulfate sodium; SEM, standard error of the mean.
a Visceral organ weights in rats following adjustment for body weight (n = 8/group). DSS was administered between days 5 and 13 and rats were sacrificed on day 13. Data are expressed as mean (% relative to body weight) ± SEM.
Gastrointestinal Organ Weights.a
Abbreviations: DSS, dextran sulfate sodium; SEM, standard error of the mean.
a Gastrointestinal organ weights in rats following adjustment for body weight (n = 8/group). DSS was administered between days 5 and 13 and rats were sacrificed on day 13. Data are expressed as mean (% relative to body weight) ± SEM.
Gastrointestinal Organ Lengths.a
Abbreviations: DSS, dextran sulfate sodium; SEM, standard error of the mean.
a Gastrointestinal organ lengths of rats (n = 8/group). DSS was administered between days 5 and 13 and rats were sacrificed on day 13. Data are expressed as mean (cm) ± SEM.
Colonic Histology
Crypt depths in the proximal and distal colon were unaffected in rats receiving dextran sulfate sodium compared to healthy controls (P > .05). Cmed and Iberogast did not significantly affect colonic architecture (Figure 4).

Crypt depth in the proximal and distal colon of rats (n = 8/group). Dextran sulfate sodium (DSS) was administered between days 5 and 13 and rats were sacrificed on day 13. Data are expressed as mean (μm) ± standard error of the mean.
Discussion
The use of plant and herbal extracts to ameliorate inflammatory disorders has been practiced for centuries. However, only recently have well-controlled studies of specific extracts been conducted in preclinical (animal model) systems. Previous in vitro studies have demonstrated antioxidant properties of Iberogast and its constituents. 28,29 Lemon balm and peppermint leaves have been reported to possess potent radical scavenging capabilities in a xanthine oxidase test reaction that investigated Iberogast and its components for responses to oxidative stress. 14 Furthermore, Iberogast decreased myeloperoxidase-driven reactions by 33% in vitro by inducing reactive oxygen species. 30 Previous experiments have investigated the effects of Iberogast on inflammatory models including mucositis and Crohn’s disease, demonstrating reduced inflammation in different regions of the gastrointestinal tract. 17,31,32 Indeed, recently, efficacy has been reported against experimental colitis in a rat model, 33 although therapeutic benefit was only evident at very high dose rates (5 mL/kg) that would equate to several hundred milliliters per day for human subjects. Several herbal remedies have improved parameters associated with colitic damage including the Garcinia cambogia extract. Jackson et al 19 reported a significant decrease in the disease activity index and a decrease in myeloperoxidase activity in mice with dextran sulfate sodium–induced colitis following administration of a combination of herbal extracts.
Five main substance classes comprise Iberogast: terpenes, volatile oil, coumarines, flavonoids, and phenol carboxylic acids. 18 Flavonoids and phenol carboxylic acid contain radical scavenging properties that target reactive oxygen species including peroxynitrate and hydrogen peroxide. The current study demonstrated that the highest concentration of Iberogast tested (200 μL/mL) only minimally improved colitic disease activity on day 10 and did not improve any of the histologically assessed parameters of colonic integrity in the dextran sulfate sodium–induced model of ulcerative colitis in rats. Presumably, small intestinal degradation and metabolism of Iberogast during its transit through the bowel may have decreased its bioavailability and hence its bioactivity at the mucosal interface of the more distal bowel regions. This would account for its lack of effectiveness in the distal colon compared to its previously reported efficacy in the more proximal intestinal regions. Microencapsulation or enema-based routes of Iberogast administration could therefore be indicated in an attempt to combat inflammatory disorders affecting the more distal regions of the alimentary tract.
In the current study, Cmed only minimally improved crypt depth, just failing to attain statistical significance. In previous studies, Astragalus root, one of the constituents of Cmed, has been shown to downregulate inducible nitric oxide synthase in dinitro benzene sulfonic acid–induced colitic rats. 23 Histological damage and elevated colonic myeloperoxidase activity by dinitro benzene sulfonic acid was reduced by Astragalus root treatment. 23 Also there was a marked reduction in the expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α in zymosan-induced air pouches in mice treated with astragalus, although the precise mechanisms remain undefined. 34–36
Barley, incorporated in many traditional Chinese medicine preparations, contains insoluble protein and dietary fiber that has demonstrated attenuation of diarrhea, reduction of colonic mucosal damage, and induction of remission in colitic rats. 22 Germinated barley foodstuff reduced the clinical activity of ulcerative colitis in both short-term and long-term administration studies, with no apparent side-effect. 37–39 The potential mechanism for germinated barley foodstuff action is believed to be the ability to maintain epithelial cells, facilitate epithelial repair, and suppress epithelial nuclear factor kappa B-DNA binding activity. 40 3,4-Dihydroxybenzaldehyde derived from purified barley attenuated cell death and apoptosis induced by hydrogen peroxide when evaluated by the 1,1-diphenyl-2-picryl hydrazyl free radical scavenging activity assay. 41
Lycium fruit (Lycium barbarum), a further constituent of Cmed, has also been demonstrated to decrease inducible nitric oxide synthase levels and glutathione peroxidise activity in streptozotocin-induced diabetic rats. 24 Polysaccharides are major constituents of Lycium fruit, believed to be responsible for the antioxidant effects, 24,42 possibly due to its ability to increase the activity of superoxide dismutase and protect against lipid peroxidation in biological membranes. 24,42 Changtai granule, a traditional compound of traditional Chinese medicine, has been reported to attenuate macroscopic and histological colon injury in the 2,4,6-trinitrobenzene sulfonic acid model of colitis in rats. 43,44 Indeed, these investigators reported a decrease in mucosal mRNA levels for several inflammatory mediators, including inducible nitric oxide synthase and tumor necrosis factorα. 43,44 Similarly, Si-Ni-San, a traditional Chinese medicine formulation, resulted in a decreased severity score and myeloperoxidase activity in a mouse model of 2,4,6-trinitrobenzene sulfonic acid–induced colitis. 41 Furthermore, Si-Ni-S caused a decrease in inferferon-γ, interleukin-12, tumor necrosis factor-α, and interleukin-17 levels. 45 Similarly, Yun Nan BaiYao, a traditional Chinese herbal remedy used for treating hemorrhages and wounds, decreased the levels of several pro-inflammatory cytokines in the colonic mucosa, including tumor necrosis factor-α, interleukin-12, and interleukin-17, in both the dextran sulfate sodium–induced and 2,4,6-trinitrobenzene sulfonic acid–induced models of colitis. 46 The recent finding that the natural plant product sophocarpine ameliorates dextran sodium sulfate–induced colitis in mice by regulating cytokine balance 47 indicates that future studies of traditional Chinese medicine preparations in models of experimentally induced ulcerative colitis should consider effects on systemic and mucosal cytokine profiles as a firstline analytical measure.
Conclusions
In conclusion, although there was only minimal improvement in colonic structure in colitic rats following administration of Iberogast and Cmed, the findings of the current study support further preclinical studies in which other plant-sourced formulations could be tested for the potential treatment of colitis. Combining histological and immunological (cytokine profile) end-points is recommended for future studies. Although the mechanism of action of these extracts is complex, further studies could address the potential for combinations of plant extracts such as Iberogast and Cmed to increase clinical efficacy, either by additive or synergistic means. Maximizing bioavailability of these formulations, either by encapsulation or enema administration, could represent a future strategy to target the specific site of injury in inflammatory disorders affecting the distal bowel.
Footnotes
Acknowledgments
The authors would like to thank Esther Burt and Betty Zacharakis for analysis of breath samples.
Author Contributions
SM significantly contributed toward animal trials, experiments and data analyses, and prepared the final version of the article. BVH and MV conducted all animal trials, experiments and data analyses, and contributed toward the preparation of the article. KAL significantly contributed toward the animal trials. CF-B assisted with experimental planning and analysis of data. GSH contributed to the experimental design, analysis of data, and preparation of the article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship and/or publication of this article: Professor Gordon S. Howarth is supported by the Sally Birch Cancer Council Australia Senior Research Fellowship in Cancer Control.
Ethical Approval
All animal experiments were performed with ethical approval from the animal ethics committees of the Women’s and Children’s Hospital and The University of Adelaide, in compliance with The Australian Code of Practice for the Care and Use of Animals for Scientific Purposes.
