Immune effects and antiacetylcholinesterase activity of Polygonum hydropiper L

Abstract

To determine the potential utility of Polygonum hydropiper (tade) as an anti-dementia functional food, the present study assessed the acetylcholinesterase inhibitory and anti-inflammatory activities of tade crude extracts in human cells. Crude extracts of tade were obtained by homogenizing tade in distilled water and then heating the resulting crude extracts. The hot aqueous extracts were purified by centrifugation and freeze-dried. The inhibition of acetylcholinesterase (AChE) by tade was investigated quantitatively by Ellman's method. Furthermore, the in vitro effects on human leukocytes (phagocytic activity, phagosome-lysosome fusion, and superoxide anion release) of coating inactive Staphylococcus aureus cells with tade crude extracts were studied. The tade crude extracts inhibited AChE activity. Furthermore, they increased phagocytic activity and phagosome-lysosome fusion in human neutrophils and monocytes in a nominally dose-dependent manner. However, the tade crude extracts did not alter superoxide anion release (O2 (-)) from neutrophils. Our results confirmed that crude extracts of P. hydropiper exhibit antiacetylcholinesterase and immunostimulation activities in vitro. P. hydropiper thus is a candidate functional food for the prevention of dementia.

Keywords: Polygonum hydropiper; anti-acetylcholinesterase; functional food; phagocytosis; phagosome-lysosome fusion; superoxide anion release.

Fig. 1.

Effects of Ayutade and Benitade crude extracts on acetylcholinesterase activity. The inhibition of acetylcholinesterase by Polygonum hydropiper crude extracts was studied quantitatively using the Ellman method with acetylthiocholine iodide as the substrate.

Fig. 2.

Effects of tade crude extracts on phagocytosis by human neutrophils. Values represent the mean ± SD. ***p<0.001, significantly different from control.

Fig. 3.

Effects of tade crude extracts on phagocytosis by human monocytes. Values represent the mean ± SD. **p<0.01, significantly different from control; ***p<0.001, significantly different from control.

Fig. 4.

Effect of Ayutade crude extracts on phagosome-lysosome fusion by neutrophils. Fusion index was defined as the percentage of positive fusion multiplied by the mean number of fused phagosomes per cell. Values represent the mean ± SD. *p<0.05, significantly different from control; **p<0.01, significantly different from control.

Fig. 5.

Effect of Ayutade crude extracts on superoxide anion release from human neutrophils. Results are shown as the mean ± SD of three different experiments. Results were not significantly different from those of the (–) controls.