Microencapsulation of tannic acid for oral administration to inhibit carbohydrate digestion in the gastrointestinal tract

Abstract

The prevalence of diabetes mellitus and obesity is rapidly rising worldwide. Recently, there is increasing evidence that phytochemicals such as polyphenols in our diet could directly inhibit the activities of key digestive enzymes, representing a novel method of controlling and preventing diabetes mellitus and obesity. More research is required to determine how to effectively utilize phytochemicals within the gastrointestinal (GI) tract to obtain maximum inhibition of digestive enzymes. This study investigated the inhibition efficiency of tannic acid (TA) on α-amylase as compared with other potential inhibitors using an in vitro method. The inhibition mode and kinetics were studied. The results showed that tannic acid (TA) is more effective in inhibiting α-amylase than a commercial starch blocker (Phase 2 Starch Blocker), and some selected flavonoids and polyphenols including quercetin, rutin, and polyphenon from green tea. It is also found that inhibition of α-amylase by TA in the GI tract is difficult if administered orally due to the non-specific and reversible noncompetitive interaction between tannic acid and α-amylase or other proteins. Accordingly, a pH-sensitive delivery system using calcium-alginate microspheres encapsulating tannic acid was successfully developed for oral administration to inhibit carbohydrate digestion in the GI tract. The encapsulated TA in calcium-alginate microspheres could be protected from the proteins in the stomach, and sustain release and inhibit α-amylase activity in the small intestine.

Sorghum condensed tannins encapsulated in kafirin microparticles as a nutraceutical for inhibition of amylases during digestion to attenuate hyperglycaemia

“…Encapsulation efficiency of SCT in KEMS by the aqueous ethanol method was similar to that obtained by other workers who encapsulated tea catechins in chitosan-tripolyphosphate nanoparticles (Hu, Pan, Sun, Hou, Ye, Hu & Zeng, 2008) and tannic acid in calcium alginate microspheres (Zhao et al, 2013) using coacervation. …”

“…Zhao, Iyer, Flores, Donhowe & Kong (2013) demonstrated that by encapsulating tannic acid in calcium alginate microspheres, α-amylase could be substantially inhibited in the small intestine phase in a simulated gastrointestinal digestion. Kafirin, the sorghum prolamin storage protein, is notably hydrophobic and resistant to pepsin digestion (Belton, Delgadillo, Halford & Shewry, 2006).…”

Grape skin phenolics as inhibitors of mammalian α-glucosidase and α-amylase – effect of food matrix and processing on efficacy

“…Binding of polyphenols with protein molecules is driven by hydrogen bonding or hydrophobic interaction leading to the formation of soluble or insoluble polyphenol-protein aggregates. [32][33][34] The main features of the polyphenol structure that influence their interactions with protein have been reported to be the number of galloyl ester groups and the degree of polymerization. 35 In fact, heat changes associated with the addition of a model proline-rich peptide to non-galloylated monomers (catechin and epicatechin) were negligible compared to the addition of galloylated monomers (epicatechin gallate, with binding constant of 8.1 × 10 4 M −1 ) and especially to flavanol oligomers (mean degree of polymerization 4, with binding constant of 34.3 × 10 4 M −1 ).…”

Effect of tannic acid–fish scale gelatin hydrolysate hybrid nanoparticles on intestinal barrier function and α-amylase activity

“…10 A reaction mixture of starch solution (1%) and α-amylase solution (1-5 U ml −1 ) was incubated at 37°C and was subsequently assayed by measuring the absorbance at 540 nm. The α-amylase inhibitory assay was performed using starch as a substrate (1.0 w/v) with or without tannic acid (0.5 mg ml −1 ) or nanoparticles (0.5 mg tannic acid eq.…”