Herbal medicines for the management of irritable bowel syndrome: A comprehensive review

Table 1 Single herbs used for treatment of irritable bowel syndrome

Scientific name	Part	Type of study	Model	Concomitant drugs	Duration of study	Results	Ref.
Aloe vera	Gel	Placebo-controlled double-blind trial	IBS patients	-	1 mo	No difference between treatment and placebo groups in response to treatment at 1 mo diarrhea-predominant patients showed a trend towards a response to treatment at 1 mo	[17]
Curcuma longa	Rhizome	Partially blinded, randomized, two-dose, pilot study	IBS patients	-	8 wk	↓Abdominal pain/discomfort score Significant improvements in IBS QOL scales Approximately two thirds of all subjects reported an improvement in symptoms after treatment	[18]
Curcuma xanthorrhiza	Rhizome	Randomized, double-blind, placebo-controlled trial	IBS patients	-	18 wk	↑IBS-related pain ↓IBS-related distension but more decrease was seen in placebo The global assessment of changes in IBS symptoms and psychological stress due to IBS did not differ significantly among groups	[19]
Cynara scolymus	Aqueous-alcohol extract of leaf	Postmarketing surveillance study	IBS patients	-	6 wk	↓Severity of symptoms reported by both physicians and patients 96% of patients rated this drug as better than or at least equal to previous therapies Very good tolerability	[24]
	Aqueous extract of leaf	Dose-ranging, open, postal study	IBS patients	-	2 mo	↓IBS incidence by 26.4% A significant shift in self-reported usual bowel pattern away from “alternating constipation/diarrhea” toward “normal”↓NDI total symptom score by 41% 20% improvement in the NDI total QOL score	[23]
Fumaria officinalis	Whole plant	Randomized, double-blind, placebo-controlled trial	IBS patients	-	18 wk	↓IBS-related pain ↑IBS-related distension The global assessment of changes in IBS symptoms and psychological stress due to IBS did not differ significantly among group	[19]
Hypericum perforatum	Aerial parts	Randomized, double-blind, placebo-controlled trial	IBS patients	-	12 wk	↓Overall BSS in both groups with the placebo arm having significantly lower scores at 12 wk compared with Hypericum group A similar proportion of subjects in each treatment group believed that the study drug they received decreased IBS life interferences	[28]
		Open-label, uncontrolled trial	IBS women	-	8 wk	↓autonomic nervous system to different stressor Improvement of Gastrointestinal symptoms of IBS	[29]
Iberis amara	Whole plant extract	Double-blind, randomized, placebo-controlled, multi-centre trial	IBS patients	-	4 wk	Significant improvement in IBS symptom scale and abdominal pain scale in Iberis group compared with placebo	[44]
Maranta arundinacea	Root	Uncontrolled	Diarrhea predominant- IBS patients	-	1 mo	↓Diarrhoea ↓Abdominal pain	[30]
Menthe piperita	Essence	Prospective double blind placebo-controlled randomized trial	IBS patients	-	4 wk	75% of the patients in the treatment group showed a > 50% reduction of basal total IBS symptoms score compared with 38% in the placebo group (P < 0.009) a statistically significant reduction of the total IBS symptoms score in treatment group compared with T (0), while no change was found with the placebo	[34]
		Randomized double-blind placebo-controlled study	IBS patients	-	8 wk	The number of subjects free from abdominal pain or discomfort changed from 0 at wk 0 to 14 at wk 8 in the treatment group and from 0 to 6 in controls (P < 0.001). ↓Severity of abdominal pain significantly in the drug group as compared to controls Improvement in the QOL in the treatment group There was no significant adverse reaction	[33]
		Randomized, double-blind controlled trial	IBS patients	-	2 wk	76% of the patients receiving peppermint oil reported changes in the severity of symptom scale at the end of trial compared with 19% receiving placebo	[35]
						Improvements in the change of symptom scale in 71% of the patients receiving peppermint oil compared with 43% receiving placebo
						No significant differences between groups in the Gastrointestinal Symptom Rating Scale
						No changes in symptoms such as abdominal rumbling, abdominal distention, belching, gas, and heartburn in treatment group compared with placebo
						Mean severity of pain symptoms in the treatment group was significantly lower than that in the placebo
			IBS patients	-	1 mo	Significant reduction in the abdominal pain, abdominal distension, stool frequency, borborygmi, flatulence in the treatment group compared to placebo	[32]
						Symptom improvements after essence therapy were significantly better than after placebo
						No significant changes in liver function test results.
Paeonia lactiflora	Paeoniflorin; Active principle of root	In vivo	Neonatal maternal separation-induced visceral hyperalgesia in rats	-	Single dose	A dose-dependent analgesic effect Blockage of analgesic effect of Paeoniflorin by nor-binaltorphimine, dl-α-methyltyrosine, and yohimbine. Analgesic effect may be mediated by kappa-opioid receptors and α(2)-adrenoceptors in the central nervous system	[39]
Plantago psyllium	Seed	Randomized placebo controlled trial	IBs patients	-	12 wk	Significantly greater proportion of responders in the psyllium group than in the placebo group	[40]
						↓Symptom severity significantly in the psyllium group compared with the placebo
						No differences in QOL

IBS: Irritable bowel syndrome; QOL: Quality of life; NDI: Nepean dyspepsia index; BSS: Bowel symptom score.