Effect of the molecular weight of water-soluble chitosan on its fat-/cholesterol-binding capacities and inhibitory activities to pancreatic lipase

Abstract

BackgroundObesity has become a worldwide burden to public health in recent decades. Given that obesity is caused by an imbalance between caloric intake and expenditure, and that dietary fat is the most important energy source of all macronutrients (by providing the most calories), a valuable strategy for obesity treatment and prevention is to block fat absorption via the gastrointestinal pathway. In this study, the fat- and cholesterol-binding capacities and the inhibition of pancreatic lipase by water-soluble chitosan (WSC) with different weight-average molecular weight (Mw) were tested and compared in vitro, in order to determine the anti-obesity effects of WSC and the influence of its Mw.MethodsIn this study, WSC with different Mw (∼1,000, ∼3,000, ∼5,000, ∼7,000 and ∼9,000 Da) were prepared by oxidative degradation assisted with microwave irradiation. A biopharmaceutical model of the digestive tract was used to determine the fat- and cholesterol-binding capacity of WSC samples. The pancreatic lipase assays were based on p-nitrophenyl derivatives.ResultsThe results showed that all of the WSC samples exhibit great fat- and cholesterol-binding capacities. Within the testing range, 1 g of WSC sample could absorb 2–8 g of peanut oil or 50–65 mg of cholesterol, which are both significantly higher than the ability of cellulose to do the same. Meanwhile, all the WSC samples were proven to be able to inhibit pancreatic lipase activity to some extent.DiscussionBased on the results, we suggest that there is a significant correlation between the binding capacity of WSC and its Mw, as WSC2 (∼3,000 Da) shows the highest fat- and cholesterol-binding capacities (7.08 g g−1 and 63.48 mg g−1, respectively), and the binding ability of WSC declines as its Mw increases or decreases from 3,000 Da. We also suggest WSC as an excellent resource in the development of functional foods against obesity for its adsorption, electrostatic binding and entrapment of cholesterol, fat, sterols and triglycerides in the diet.

ADME-Tox profiling of some water soluble chitosan derivatives

“…Furthermore, the investigated compounds do not reveal carcinogenic potential and cardiac toxicity, but they are predicted to induce phospholipidosis and to have some adverse effects: weight loss, acidosis, gastrointestinal toxicity, respiratory failure. Some of the predicted pharmacological and toxicological profiles of the considered WSDC are in good agreement with a few experimental studies revealing that WSDC have no or low cytotoxicity [28,29], no genotoxicity [28], have fat-and cholesterol-binding capacities producing weight loss [30]. Their side effects increase with the molecular weight and degree of deacetylation [31].…”

Correlations of Molecular Weights of β-Glucans from Qingke (Tibetan Hulless Barley) to Their Multiple Bioactivities

“…The fa- binding capacities of Qingke β-glucans with different molecular weights (BG, BGD1, and BGD2) were measured according to a previously reported method with some modifications [ 33 ]. Briefly, 20 mg of each β-glucan was dissolved in 2.0 mL of pure water.…”

“…The cholesterol-binding capacities of Qingke β-glucans with different molecular weights were measured according to a previously reported method with minor modifications [ 33 ]. Briefly, 20 mL of cholesterol micellar solution were prepared by sonication at 480 W for 1 h (PL-S80TX, Kangshijie company, Guangdong, China), composed of 10 mM sodium taurocholate, 5 mM cholesterol, 5 mM oleic acid, 132 mM sodium chloride, and 15 mM sodium phosphate buffer (pH 7.4).…”

“…Furthermore, the inhibition of pancreatic lipase activity was measured according to previously reported methods with minor modifications [ 24 , 33 ]. Briefly, 100 µL of each Qingke β-glucan at the concentrations of 0.25, 0.5, 1.0, 2.5, 5.0 and 10.0 mg/mL was mixed with 200 µL of Tris buffer (50 mM, pH 7.4), and 100 µL of pancreatic lipase solution (5 mg/mL), and the mixture was incubated at 37 °C for 10 min with continuous shaking.…”

Water Soluble Chitosan Derivatives and their Biological Activities: A Review

“…Lastly, the collected samples were centrifuged and lyophilized to obtain powdered WSC derivatives. The produced WSC derivatives associated with MW displayed excellent fat-and cholesterol binding capacities [26]. Another study investigated the oxidative degradation of chitosan using two peroxo species as (TBA) 3 [27].…”