Effects of Native and Oxidized Phenolic Compounds on Sucrase Activity in Rat Brush Border Membrane Vesicles

Abstract

The effects of dietary phenolic compounds on intestinal sucrase were investigated in brush border membrane vesicles purified from rat small intestine. Screening experiments were conducted with different classes of phenolic compounds in both oxidized and native forms. The most potent inhibitor was native tannic acid at 0.1 mg/ml, resulting in an 80% loss of activity. Oxidized tannic acid had no effect. Significant decreases were also observed in vesicles treated with 0.1 mg/ml of catechol or epicatechin, yielding activity losses of 30-50%, regardless of oxidation state. With gallic acid, maximal (40%) inhibition occurred only in the oxidized form. Other phenolic compounds, such as ferulic, p-coumaric and caffeic acids, tended to be slightly inhibitory, while no inhibition was observed with vanillin or chlorogenic acid at the concentrations tested. These results confirm the enzyme inhibitory action of tannic acid, a polyphenolic compound, and also demonstrate that some individual dietary phenolic monomers have the potential to modulate enzyme activity in a brush border membrane vesicle model system.

Vaccinium arctostaphylos, a common herbal medicine in Iran: Molecular and biochemical study of its antidiabetic effects on alloxan-diabetic Wistar rats

“…Numerous studies have shown the relationship between phenolics and antioxidative activities (Prior et al, 1998;Joseph et al, 2005;Scalbert et al, 2005) as well as between them and inhibition of ␣-glucosidase activity (Ahmed et al, 1991;Welsch et al, 1989). Also polyphenolic compounds increased the amount of insulin-sensitive GLUT-4 (Pinent et al, 2004;Liu et al, 2005).…”

Inhibitory effect of Pistia tannin on digestive enzymes of Indian major carps: an in vitro study

“…Tannins may reduce macro nutrient utilization by forming tannin-protein complexes with various digestive enzymes precluding the formation of the product absorbable by the small intestine (Carmona et al 1996). In addition, it may inhibit transport systems concerning carbohydrate assimilation such as glucosidase/maltase (Bjorck and Nyman 1987), sucrase (Welsch et al 1989) and the intestinal sodium-dependent glucose uptake system (Karasov et al 1992). Bean tannins were shown to strongly inhibit pancreatic trypsin, chymotrypsin and a-amylase (Sing 1984;Carmona et al 1991).…”

Intestinal growth and function of broiler chicks fed sorghum based diets differing in condensed tannin levels

“…Butler (1992) has suggested that high levels of tannins can cause gastroenteritis and congestion of the intestinal wall in rats. A deficiency in sucrase activity due to tannin ingestion has been found to reduce the absorption efficiency of BBM vesicles (Welsch et al, 1989). In a study to assess the effect of dietary phenolic compounds on glucose uptake in intestinal BBM vesicles of rats, morphological changes were found to be accompanied by a severe impairment of the brush border enzyme, sucrase, to about one third of normal enzyme activity (Welsch et al, 1989).…”

“…A deficiency in sucrase activity due to tannin ingestion has been found to reduce the absorption efficiency of BBM vesicles (Welsch et al, 1989). In a study to assess the effect of dietary phenolic compounds on glucose uptake in intestinal BBM vesicles of rats, morphological changes were found to be accompanied by a severe impairment of the brush border enzyme, sucrase, to about one third of normal enzyme activity (Welsch et al, 1989). Ahmed et al (1991) deduced that this might have been the result of either direct complex formation between enzymes and tannins or through secondary effects, which led to diminished activity such as changing the gut wall morphology.…”