Arecoline Triggers Psychostimulant Responses by Modulating the Intestinal Microbiota to Influence Neurotransmitter Levels and Digestive Enzyme Activity

Abstract

Background:Areca catechu L. is an evergreen tree belonging to the Arecaceae family. As an important traditional Chinese medicine, it has wide applications in the field of herbal medicine. Arecoline is the main active component responsible for its medicinal effects and plays a key role in its central nervous system (CNS) stimulant properties. Methods: This study investigated the excitatory effects of arecoline by analyzing behavioral changes in mice, neurotransmitter levels, the intestinal microbiota composition, and enzymatic activities. We further explored the bidirectional interactions between the intestinal microbial ecosystem and the nervous system following arecoline exposure. Results: Arecoline administration significantly increased the activity time ratio in mice (p < 0.05). It also elevated fecal lactase and amylase activities (p < 0.05), suggesting enhanced carbohydrate metabolism that may be one of the reasons for the increased activity time of mice. Serum analysis showed decreased 5-hydroxytryptamine (5-HT, p < 0.05), increased dopamine (DA) and brain-derived neurotrophic factor (BDNF) levels (p < 0.001), and no significant change in γ-aminobutyric acid (GABA). These findings suggest that arecoline may also play a role in modulating neurotransmitter balance. At the genus level, Escherichia was significantly enriched and positively correlated with DA, BDNF, and GABA, while Clostridium abundance decreased and was positively correlated with 5-HT. Conclusions: Arecoline administration altered multiple enzymatic activities and the microbial composition abundance in the mouse intestine, eliciting psychostimulant effects while maintaining neurotransmitter homeostasis. This study provides an experimental foundation for further pharmacological exploitation of arecoline.

Keywords: Areca catechu L.; arecoline; enzyme activity; intestinal microbiota; neurotransmitters.

Figure 1

Open field experimental activity trajectory map.

Figure 2

Effects of arecoline on fecal enzyme activity in mice: (A): lactase activity; (B): sucrase activity; (C): protease activity; (D): amylase activity. Values are expressed as mean ± standard deviation (n = 3). * p < 0.05, ** p < 0.01, *** p < 0.001.

Figure 3

Effects of arecoline on GABA, BDNF, DA, and 5-HT in mice. Values are expressed as mean ± standard deviation (n = 5). (A): GABA; (B): 5-HT; (C): DA; (D): BDNF. * p < 0.05, *** p < 0.001.

Figure 4

Effects of arecoline on the microbial abundance and diversity of intestinal contents in mice. (A): Shannon rarefaction curve; (B): Chao1 rarefaction curve; (C): Venn diagram (ASV level); (D): Alpha diversity indices (Chao1 index, Observed_species index, Simpson index, Shannon index); (E): principal coordinate analysis (PCoA); (F): nonmetric multidimensional scaling (NMDS).

Figure 5

Effect of arecoline on the dominant microbiota of the intestinal contents of mice: (A): relative abundance at the phylum level; (B): relative abundance at the genus level; (C,D): differential phyla; (E,F): differential genera. * p < 0.05.

Figure 6

Effect of arecoline on the characteristic microbiota of the intestinal contents if mice: (A): bar plot of differentially abundant species (LDA ≥ 2); (B): genus-level random forest analysis; (C): genus-level ROC analysis (CC vs. CB).

Figure 7

Correlation analysis between the intestinal microbiota and neurotransmitters: (A): redundancy analysis (RDA), (B): scatter plots of Escherichia with GABA, DA, 5-HT and BDNF; (C): scatter plots of Clostridium with GABA, DA, 5-HT and BDNF.

Figure 8

Mechanism diagram of arecoline’s stimulatory effects. The red upward arrow represents an increase, the blue downward arrow represents a decrease.