Sulphated Polysaccharide Isolated from the Seaweed Gracilaria caudata Exerts an Antidiarrhoeal Effect in Rodents

Abstract

Diarrhoea is a significant health problem for children in developing countries that causes more than 1 million deaths annually. This study aimed to evaluate the antidiarrhoeal effect of sulphated polysaccharide (PLS) from the alga Gracilaria caudata in rodents. For the evaluation, acute diarrhoea was induced in Wistar rats (150-200 g) by administration of castor oil (10 mg/kg). Then, different parameters, including enteropooling and gastrointestinal transit and its pharmacological modulation by opioid and cholinergic pathways, were assessed using activated charcoal in Swiss Mice (25-30 g). Secretory diarrhoea was examined using cholera toxin (CT) (1 mg/loop)-treated, isolated intestinal loops from Swiss mice (25-30 g), which were also used to examine fluid secretion, loss of chloride ions into the intestinal lumen and absorption. In addition, a GM1-dependent ELISA was used to evaluate the interaction between PLS, CT and the GM1 receptor. Pre-treatment with PLS (10, 30 and 90 mg/kg) reduced faecal mass, diarrhoeal faeces and enteropooling. However, 90 mg/kg more effectively reduced these symptoms; therefore, it was used as the standard dose in subsequent experiments. Gastrointestinal transit was also reduced by PLS treatment via a cholinergic mechanism. Regarding the diarrhoea caused by CT, PLS reduced all study parameters, and the ELISA showed that PLS can interact with both the GM1 receptor and CT. These results show that PLS from G. caudata effectively improved the parameters observed in acute and secretory diarrhoea, which affects millions of people, and may lead to the development of a new alternative therapy for this disease.Seaweeds (marine macroalgae) are excellent sources of pharmacologically active compounds, and the number of substances isolated from seaweed sources has been generating a great deal of interest [1]. The structures of most isolated compounds have been determined, and the therapeutic potentials of these substances are currently being examined [2,3]. Investigations into the precise phytochemical composition of different seaweeds have revealed that they are principally composed of different types of sulphated polysaccharides and other potentially useful chemical biomolecules [4].Over the past several decades, it has become clear that sulphated polysaccharides are involved in numerous cellular processes and possess a range of pharmacological activities; therefore, they have attracted the attention of numerous research groups [5]. Sulphated polysaccharides are complex macromolecular compounds found in the extracellular matrix, and these polysaccharides are known to have anticoagulant, antiviral and anti-inflammatory activities that have potential applications as nutraceuticals, cosmetics and pharmaceuticals [6].In Brazil, several species of the genus Gracilaria, including Gracilaria caudata, thrive in coastal regions. We showed that G. caudata produces an agaran consisting of alternating residues of 3-linked-b-D-galactopyranose connected to either 4-linked-3,6-anhydro-a-L-galactopyr...

Biopolymer Extracted from Anadenanthera colubrina (Red Angico Gum) Exerts Therapeutic Potential in Mice: Antidiarrheal Activity and Safety Assessment

“…Pretreatment with naloxone did not impair the effects of RAG (60 mg/kg) treatment (30.9% inhibition), although it prevented the activity of loperamide (Figure 4a). Therefore, the antidiarrheal effect of RAG is not dependent on an opioid mechanism and a similar result has been observed with polysaccharides extracted from red algae [45][46][47]. Thus, RAG may delay gastrointestinal transit by other mechanisms that modulate gastrointestinal motility.…”

“…Additionally, the determination of the solubility of RAG at different pHs was performed, and the results are provided in Table 1. RAG showed high solubility at all pH values tested, especially in acidic and basic media, corresponding with the pH found in certain regions in the gastrointestinal tract such as the stomach and the intestines [44], the main sites of action of polysaccharides tested by our research group [31,32,[45][46][47]. The structure of RAG is rich in hydroxyl (OH) groups (Figure 1a), which provides a high degree of hydration leading to greater biopolymer interaction with water and consequently greater solubility [48].…”

“…Some in vitro studies have shown that several compounds can act as analogue receptors or anti-adhesive agents for GM1, such as galactose derivatives [78], phenyl-ring containing galactose derivatives [79], sialyloligosaccharides (SOS) [80,81], sulfated polysaccharides [45][46][47]57], and biopolymers extracted from the trunk exudates of trees [32], and they may offer a promising alternative to conventional treatment strategies. All these compounds mentioned are structurally similar and contain galactose, and similarly, the chemical characterization of RAG reported that it contains 24.1% galactose in % weight [26,82].…”

Nutraceutical Potential of Seaweed Polysaccharides: Structure, Bioactivity, Safety, and Toxicity

“…This polysaccharide is therefore being considered for use as a functional food ingredient for the treatment of inflammatory diseases (Sanjeewa, Lee, Kim, & Jeon, ). Sulfated polysaccharides from Gracilaria caudate have shown antidiarrheal effects on cholera toxin (CT)‐treated Swiss mice via cholinergic mechanisms acting on both the GM1 (monosialoganglioside) receptor and CT (Costa et al., ).…”

A comprehensive review of therapeutic approaches available for the treatment of cholera

“…Bezerra et al [69] ; Leodido et al [70] ; Costa et al [71] ; Sousa et al [72] a-Terpineol (a-TPN) (monoterpene) Negreiros et al [75] Farnesol (3,7,11-trimethyldodeca-2,6,10-trien-1-ol) (monoterpene) Costa et al [76]…”