The Effects of Different Degrees of Procyanidin Polymerization on the Nutrient Absorption and Digestive Enzyme Activity in Mice.

Yong Xue,Qiang Shao,Xiaoyuan Lu,Yuelei Cao,Huairong Zhong,Gao Chen,Zhaoxia Wu

doi:10.3390/molecules23112916

Abstract

Proanthocyanidins, including polymers with both low and high degrees of polymerization, are the focus of intensive research worldwide due to their high antioxidant activity, medicinal applications, and pharmacological properties. However, the nutritional value of these compounds is limited because they readily form complexes with proteins, polysaccharides, and metal ions when consumed. In this study, we examined the effects of proanthocyanidins with different degrees of polymerization on white mice. Twenty-four male white mice were randomly divided into three groups of eight mice each and fed proanthocyanidins with a low degree of polymerization or a high degree of polymerization or a distilled water control via oral gavage over a 56-day period. We examined the effects of these proanthocyanidins on digestive enzyme activity and nutrient absorption. Compared to the control group, the group fed high-polymer proanthocyanidins exhibited a significant reduction in net body mass, total food intake, food utility rate, amylase activity, protease activity, and major nutrient digestibility (p < 0.05), while the group fed low-polymerization proanthocyanidins only exhibited significant reductions in total food intake, α-amylase activity, and apparent digestibility of calcium and zinc (p < 0.05). Therefore, proanthocyanidins with a high degree of polymerization had a greater effect on digestive enzyme activity and nutrient absorption than did those with a low degree of polymerization. This study lays the foundation for elucidating the relationship between procyanidin polymerization and nutrient uptake, with the aim of reducing or eliminating the antinutritional effects of polyphenols.

Highlights

Proanthocyanidins are a large class of polyphenolic compounds produced by a wide range of plants
The initial body weights of mice in the experimental groups were not significantly different from those of the control group, after a 56-day treatment with high- or low-polymer proanthocyanidins or a distilled water control, the body weight of mice in the high-polymer group was significantly lower than that of the control group (p < 0.05), whereas that of mice in the low-polymer group was not (p > 0.05; Table 1). These results indicate that proanthocyanidins with a high degree of polymerization affect the normal growth and development of mice
The food utility rate of mice in the low-polymer group was lower than that of the control group, the difference was not significant (p > 0.05). These results indicate that high-polymer proanthocyanidins reduce the food utilization rate of mice. These results suggest that high-polymer proanthocyanidins have a stronger tendency than low-polymer proanthocyanidins to form complexes with enzymes and biological macromolecules such as proteins, fats, and sugars, resulting in a lower nutrient utilization rate

Summary

Introduction

Proanthocyanidins are a large class of polyphenolic compounds produced by a wide range of plants. Numerous studies conducted worldwide have examined the physiological activity and medicinal value of proanthocyanidins [3,4,5], and these compounds have increasingly been used to prevent and treat disease. Due to their polyhydroxy structure, proanthocyanidins readily undergo complexation reactions with proteins, polysaccharides, and metal ions, reducing the nutritional value of these compounds [6,7]. The molecular weight of polyphenols affects their ability to bind to proteins; polyphenols with a molecular weight of less than 500 kD rarely precipitate with proteins in vitro [9]

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Discussion

Conclusion