Guar, Cluster Bean

Description

Cyamopsis tetragonoloba (family Fabaceae), commonly known as guar or cluster bean, is an annual leguminous plant native to the Indian subcontinent and now cultivated in Africa, the United States, and Australia. It is valued both as a food crop and as a major source of guar gum, a natural polysaccharide extracted from the seeds and widely used as a thickening, stabilizing, and emulsifying agent in food, cosmetic, and industrial applications.
Guar is a hardy, drought-tolerant plant capable of growing in poor, sandy soils, making it a sustainable crop for semi-arid environments.

Botanical classification

Kingdom: Plantae
Clade: Angiosperms
Order: Fabales
Family: Fabaceae
Genus: Cyamopsis
Species: C. tetragonoloba

Plant characteristics

• Habit: Erect annual herb, 50–120 cm tall, with branched, robust stems.

• Leaves: Alternate, trifoliate, with oval to lanceolate leaflets of light green color.

• Flowers: Small, white to pink, typical of Fabaceae, arranged in axillary racemes.

• Fruits: Linear pods (5–12 cm long) containing 5–10 oval seeds, brown to grayish.

• Roots: Deep taproot system with nitrogen-fixing nodules formed by symbiotic bacteria.

• Habitat: Tropical and subtropical semi-arid regions, up to 1000 m altitude.

Chemical composition (main constituents of the seeds)

• Galactomannans (guar gum): high-molecular-weight polysaccharides composed of mannose and galactose in a 2:1 ratio — responsible for thickening and viscosity.

• Proteins: 20–30%, containing essential amino acids (lysine, arginine).

• Lipids: 2–3%, mainly unsaturated fatty acids.

• Insoluble fibers: support intestinal transit and digestive function.

• Minerals: iron, calcium, magnesium, phosphorus.

• Vitamins: small amounts of B-complex vitamins.

Cultivation and growing conditions

• Climate: Hot and dry; thrives in subtropical regions with moderate rainfall.

• Exposure: Full sun.

• Soil: Light, sandy or clayey, well-drained, pH 6–8; tolerant of salinity.

• Irrigation: Minimal; excess water reduces seed yield.

• Sowing: Spring to early summer, directly in the field; rapid germination.

• Harvesting: 3–4 months after sowing, when pods are mature and dry.

• Crop rotation: Improves soil fertility through nitrogen fixation.

Uses and benefits (traditional and supported by preliminary scientific evidence)

• Food use: Seeds and guar gum are rich in soluble fiber, used as natural thickeners and stabilizers in foods, beverages, and dietary products.

• Hypoglycemic and hypocholesterolemic: Fiber slows sugar and fat absorption, helping regulate blood glucose and lipid levels.

• Digestive and satiating: Improves intestinal regularity and promotes fullness.

• Animal feed: Residues from seed processing are used as high-protein fodder.

• Industrial: Guar gum is used in cosmetics, pharmaceuticals, paper, textiles, and oil drilling fluids.

Scientific studies confirm guar fiber’s cholesterol- and glucose-lowering effects, though caution is advised when combined with medications due to potential absorption interference.

Applications

• Food industry: Thickener and stabilizer in sauces, yogurts, ice creams, beverages, and bakery products.

• Herbal and nutraceutical: Soluble fiber supplement promoting intestinal regularity.

• Cosmetics: Viscosity agent in creams, gels, shampoos, and toothpastes.

• Industrial: Used in paper, textile, and paint manufacturing, and as a component in drilling muds.

• Pharmaceutical: Binder and excipient in tablets and oral suspensions.

Harvesting and processing

• Harvesting: Manual or mechanical, when pods are fully dry and mature.

• Drying: In ventilated areas or under the sun until completely dehydrated.

• Dehusking and milling: Separate the endosperm, which is the source of guar gum.

• Extraction: Mechanical processing and purification yield fine guar gum powder.

Environmental considerations

Guar is a sustainable crop due to its drought resistance and ability to enrich soil fertility via nitrogen fixation. It requires minimal water and low fertilizer input. As a rotation crop, it supports soil health and biodiversity, making it important for sustainable agriculture in arid and semi-arid regions.

Safety, contraindications, interactions

Generally regarded as safe when consumed in common dietary amounts.

• Side effects: High doses of guar gum may cause bloating or flatulence.

• Precautions: Individuals taking diabetes or cholesterol medications should consult a doctor, as guar may affect drug absorption.

• Allergies: Rare, related to individual hypersensitivity.

• Pregnancy and lactation: Moderate dietary use considered safe.

Common preparations (general, non-therapeutic use)

• Guar gum powder: 1–2 g per 200 ml of liquid as a thickener or fiber source.

• Fiber supplements: Capsules or sachets containing partially hydrolyzed guar gum.

• Cosmetic use: 0.2–1% as a stabilizer and thickener in gels and emulsions.

• Culinary use: Thickening agent in smoothies, soups, and desserts.

Studies

Many interesting properties, including antioxidant activity, hypocholesterolemic and prebiotic activity have been attributed by the scientific literature to this compound.

In particular, hepatoprotective activity (1) and drug release have been studied (2).

At high concentrations it can cause flatulence and swelling due to the fermentation of intestinal flora.

Guar studies

References____________________________________________

(1) Wu C, Liu J, Tang Y, Li Y, Yan Q, Jiang Z. Hepatoprotective Potential of Partially Hydrolyzed Guar Gum against Acute Alcohol-Induced Liver Injury in Vitro and Vivo.   Nutrients. 2019 Apr 27;11(5). pii: E963. doi: 10.3390/nu11050963.

Abstract. Natural polysaccharides, particularly galactomannans, are potential candidates for treatment of alcoholic liver diseases (ALD). However, applications are restricted due to the physicochemical properties associated with the high molecular weight. In this work, guar gum galactomannans were partially hydrolyzed by β-mannanase, and the molecular mechanisms of hepatoprotective effects were elucidated both in vitro and in vivo. Release of lactate dehydrogenase and cytochrome C were attenuated by partially hydrolyzed guar gum (PHGG) in HepG2 cells, due to protected cell and mitochondrial membrane integrity. PHGG co-administration decreased serum amino transaminases and cholinesterase levels of acute alcohol intoxicated mice, while hepatic pathologic morphology was depleted. Activity of superoxide dismutase, catalase, and glutathione peroxidase was recovered to 198.2, 34.5, 236.0 U/mg protein, respectively, while malondialdehyde level was decreased by 76.3% (PHGG, 1000 mg/kg∙day). Co-administration of PHGG induced a 4.4-fold increment of p-AMPK expression, and lipid metabolism was mediated. PHGG alleviated toll-like-receptor-4-mediated inflammation via the signaling cascade of MyD88 and IκBα, decreasing cytokine production. Moreover, mediated expression of Bcl-2 and Bax was responsible for inhibited acute alcohol-induced apoptosis with suppressed cleavage of caspase 3 and PARP. Findings gained suggest that PHGG can be used as functional food supplement for the treatment of acute alcohol-induced liver injury.

(2) Kumar B, Murali A, Bharath AB, Giri S. Guar gum modified upconversion nanocomposites for colorectal cancer treatment through enzyme-responsive drug release and NIR-triggered photodynamic therapy.    Nanotechnology. 2019 Mar 20;30(31):315102. doi: 10.1088/1361-6528/ab116e.

Abstract. Multimodal therapeutic approach towards colorectal cancer (CRC) holds great promise. There is, however, no convincing strategy reported to date that employs a multimodal strategy in CRC treatment. The present study reports an intense green-emitting core-shell photoluminescent upconversion (CSGU) nanocrystal engineered to synergistically perform photodynamic and enzyme-triggered delivery of the chemotherapeutic agent for an enhanced therapeutic outcome on HT-29 colon carcinoma cells in vitro. The photodynamic activity is achieved by the energy transfer between CSGU and the chemically conjugated Rose Bengal (RB) molecules that are further protected by a mesoporous silica (MS) layer. The chemical assay demonstrates a remarkable FRET mediated generation of 1O2 under NIR (980 nm) excitation. The outermost MS layer of the nanoplatform is utilized for the loading of the 5FU anticancer drug, which is further capped with a guar gum (GG) polysaccharide polymer. The release of the 5FU is specifically triggered by the degradation of the GG cap by specific enzymes secreted from colonic microflora, which otherwise showed 'zero-release behavior' in the absence of any enzymatic trigger in various simulated gastro-intestinal (GI) conditions. Furthermore, the enhanced therapeutic efficacy of the nanoplatform (CSGUR-MSGG/5FU) was evaluated through in vitro studies using HT-29 CRC cell lines by various biochemical and microscopic assays by the simultaneous triggering effect of colonic enzyme and 980 nm laser excitation. In addition, the strong visible emission from the nanoplatform has been utilized for NIR-induced cellular bioimaging.

Paudel D, Nair DVT, Tian S, Hao F, Goand UK, Joseph G, Prodes E, Chai Z, Robert CEM, Chassaing B, Patterson AD, Singh V. Dietary fiber guar gum-induced shift in gut microbiota metabolism and intestinal immune activity enhances susceptibility to colonic inflammation. Gut Microbes. 2024 Jan-Dec;16(1):2341457. doi: 10.1080/19490976.2024.2341457.

Abstract. With an increasing interest in dietary fibers (DFs) to promote intestinal health and the growth of beneficial gut bacteria, there is a continued rise in the incorporation of refined DFs in processed foods. It is still unclear how refined fibers, such as guar gum, affect the gut microbiota activity and pathogenesis of inflammatory bowel disease (IBD). Our study elucidated the effect and underlying mechanisms of guar gum, a fermentable DF (FDF) commonly present in a wide range of processed foods, on colitis development. We report that guar gum containing diet (GuD) increased the susceptibility to colonic inflammation. Specifically, GuD-fed group exhibited severe colitis upon dextran sulfate sodium (DSS) administration, as evidenced by reduced body weight, diarrhea, rectal bleeding, and shortening of colon length compared to cellulose-fed control mice. Elevated levels of pro-inflammatory markers in both serum [serum amyloid A (SAA), lipocalin 2 (Lcn2)] and colon (Lcn2) and extensive disruption of colonic architecture further affirmed that GuD-fed group exhibited more severe colitis than control group upon DSS intervention. Amelioration of colitis in GuD-fed group pre-treated with antibiotics suggest a vital role of intestinal microbiota in GuD-mediated exacerbation of intestinal inflammation. Gut microbiota composition and metabolite analysis in fecal and cecal contents, respectively, revealed that guar gum primarily enriches Actinobacteriota, specifically Bifidobacterium. Guar gum also altered multiple genera belonging to phyla Bacteroidota and Firmicutes. Such shift in gut microbiota composition favored luminal accumulation of intermediary metabolites succinate and lactate in the GuD-fed mice. Colonic IL-18 and tight junction markers were also decreased in the GuD-fed group. Importantly, GuD-fed mice pre-treated with recombinant IL-18 displayed attenuated colitis. Collectively, unfavorable changes in gut microbiota activity leading to luminal accumulation of lactate and succinate, reduced colonic IL-18, and compromised gut barrier function following guar gum feeding contributed to increased colitis susceptibility.

Todd PA, Benfield P, Goa KL. Guar gum. A review of its pharmacological properties, and use as a dietary adjunct in hypercholesterolaemia. Drugs. 1990 Jun;39(6):917-28. doi: 10.2165/00003495-199039060-00007. 

Abstract. Guar gum is a dietary fibre advocated for use in lowering serum total cholesterol levels in patients with hypercholesterolaemia. Its mechanism of action is proposed to be similar to that of the bile-sequestering resins. Although guar gum is also employed as an adjunct in non-insulin-dependent diabetic patients this review is restricted to its efficacy as a hypolipidaemic agent. Clinical trials indicate that, when used alone, guar gum may reduce serum total cholesterol by 10 to 15%, although some studies show no significant response. An attenuation of this effect during longer term treatment has been seen but evidence of this effect is equivocal. As an adjunct to established therapies (bezafibrate, lovastatin or gemfibrozil) guar gum has shown some promise: it may produce a further reduction in total cholesterol of about 10% in patients not responding adequately to these drugs alone. Gastrointestinal effects, notably flatulence, occur relatively frequently and may be considered unacceptable by some patients. Standardization of formulations and methods of administration of guar gum is required to clarify its pharmacological and clinical properties. Thus, on the basis of presently available evidence guar gum as monotherapy may be considered at most modestly effective in reducing serum cholesterol levels. Nonetheless, further investigation of guar gum is warranted, particularly its use as an adjunct to produce additional reductions in serum cholesterol in patients not responding optimally to other lipid-lowering agents.

Okamura T, Hamaguchi M, Mori J, Yamaguchi M, Mizushima K, Abe A, Ozeki M, Sasano R, Naito Y, Fukui M. Partially Hydrolyzed Guar Gum Suppresses the Development of Sarcopenic Obesity. Nutrients. 2022 Mar 9;14(6):1157. doi: 10.3390/nu14061157. PMID: 35334814; 

Abstract. Partially hydrolyzed guar gum (PHGG) is a soluble dietary fiber derived through controlled enzymatic hydrolysis of guar gum, a highly viscous galactomannan derived from the seeds of Cyamopsis tetragonoloba. Here, we examined the therapeutic potential of dietary supplementation with PHGG against sarcopenic obesity using Db/Db mice. Db/Db mice fed a normal diet alone or a fiber-free diet, or supplemented with a diet containing PHGG (5%), were examined. PHGG increased grip strength and the weight of skeletal muscles. PHGG increased the short-chain fatty acids (SCFAs) concentration in feces and sera. Concerning innate immunity, PHGG decreased the ratio of inflammatory cells, while increasing the ratio of anti-inflammatory cells in the small intestine. The present study demonstrated the preventive effect of PHGG on sarcopenic obesity. Changes in nutrient absorption might be involved through the promotion of an anti-inflammatory shift of innate immunity in the intestine accompanied by an increase in SCFA production by PHGG.