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

Abstract

Type 2 diabetes (T2D) is increasing rapidly in Africa. An appropriate therapeutic approach is to inhibit intestinal carbohydrate digesting enzymes using plant polyphenols. A crude preparation of sorghum condensed tannins (SCT) was highly effective (approx. 20,000 times) at inhibiting α-glucosidase compared to acarbose, while acarbose was a better α-amylase inhihitor (approx. 180 times). Kafirin microparticles (KEMS) were investigated as an oral delivery system for SCT. Using a simple aqueous alcohol coacervation method, the encapulation efficiency of SCT in the KEMS was approx. 48%. Quantitative data and electron microscopy revealed that KEMS encapsulating SCT were digested to only a limited extent during simulated gastrointestinal digestion with pepsin and trypsin-chymotrypsin.Hence, SCT encapsulated in KEMS retained their inhibitory activity against both amylases, throughout simulated gastrointestinal digestion, whereas unencapsulated SCT lost most of their inhibitory activity. Thus, KEMS encapsulating SCT have potential as a nutraceutical to attenuate hyperglycaemia and control T2D.

Kafirin microparticle encapsulated sorghum condensed tannins exhibit potential as an anti-hyperglycaemic agent in a small animal model

“…without encapsulation) generally showed the highest blood glucose level amongst the treatments. This was expected as our previous research showed that unencapsulated SCT lost most of their inhibitory action when subjected to simulated gastrointestinal digestion (Links et al, 2015). However, an increase in blood glucose caused by tannins has not been previously reported.…”

“…SCT were extracted from bran of red type III (high-tannin) sorghum (cultivar PAN 3860) using methanol (Links et al, 2015). The extract was dried at ambient temperature and defatted with hexane.…”

“…Water was used to coacervate the SCT/KEMS (Links et al, 2015), which was washed with water to remove unbound SCT, air-dried and milled to a fine powder. The SCT-KEMS contained 29% bound SCT.…”

“…Condensed tannins isolated from sorghum, an indigenous African cereal (sorghum condensed tannins (SCT)), strongly inhibit both α-amylase and α-glucosidase in vitro, the latter at far lower concentration than acarbose (an α-glucosidase inhibitor used for diabetes treatment) (Links et al, 2015). When SCT preparations were encapsulated in microparticles made from kafirin (sorghum prolamin protein), (KEMS), they retained inhibitory activity against both α-amylase and α-glucosidase during simulated gastrointestinal digestion.…”

Phenolic and tocopherol content of autumn olive (Elaeagnus umbellate) berries

“…Other emerging bioactivities proanthocyanidins include but are not limited to alleviating postprandial oxidative stress, attenuating the endoplasmic reticulum stress, suppressing inflammation, and modulating gut microbiota (Ahmad et al, 2014;Choy et al, 2014;Fernández-Iglesias et al, 2014;Gao et al, 2014). Furthermore, proanthocyanidins inhibit α-amylase activity and are a potential nutraceutical for glycemic control (Fu et al, 2015;Links, Taylor, Kruger, & Taylor, 2015). The proanthocyanidin content of AOB may contribute to the notably astringency or bitterness of autumn olive (Lesschaeve & Noble, 2005).…”