Acanthopanax senticosus extract alleviates radiation-induced learning and memory impairment based on neurotransmitter-gut microbiota communication

BACKGROUND

Acanthopanax senticosus (AS) is a medicinal and food plant with many physiological functions, especially nerve protection. Its extract has many functional components, including polysaccharides, flavonoids, saponins, and amino acids. Our previous study indicated that AS extract protected against nerve damage caused by radiation. However, little is known about the gut-brain axis mechanism of AS and its impact on radiation-induced learning and memory impairment.

METHOD

In 60 Co-γ ray-irradiated mice, we investigated the changes in behavior, neurotransmitters and gut microbiota after different days of administration of AS extract as a dietary supplement.

RESULTS

The AS extract improved learning and memory ability in mice, and the neurotransmitter levels in the hippocampus and colon started to change from the 7th day, which accompanied changes of the gut microbiota, a decreased abundance of Helicobacter on the 7th day and an increased abundance of Lactobacillus on the 28th day. Among the marker bacteria, Ruminococcus and Clostridiales were associated with 5-HT synthesis, and Streptococcus were associated with 5-HT and ACH synthesis. In addition, the AS extract increased the tight junction protein, inhibited inflammation levels in colon, and even increased the relative protein expression of BDNF and NF-κB and decreased the relative protein expression of IκBα in the hippocampus of irradiated mice.

CONCLUSION

These results will lay the foundation for further study on the mechanism of the gut-brain axis of AS in preventing radiation-induced learning and memory impairment.

Antioxidant Activity of Acanthopanax senticosus Flavonoids in H2O2-Induced RAW 264.7 Cells and DSS-Induced Colitis in Mice

The redox reaction is a normal process of biological metabolism in the body that leads to the production of free radicals. Under conditions such as pathogenic infection, stress, and drug exposure, free radicals can exceed normal levels, causing protein denaturation, DNA damage, and the oxidation of the cell membrane, which, in turn, causes inflammation. Acanthopanax senticosus (A. senticosus) flavonoids are the main bioactive ingredients with antioxidant function. H₂O₂-treated RAW 264.7 cells and DSS-induced colitis in mice were used to evaluate the antioxidant properties of A. senticosus flavonoids. The results show that A. senticosus flavonoids can significantly downregulate the levels of ROS and MDA in H₂O₂-treated RAW 264.7 cells and increase the levels of CAT, SOD, and GPx. A. senticosus flavonoids can also increase the body weights of DSS-induced colitis mice, increase the DAI index, and ameliorate the shortening of the colon. ELISA experiments confirmed that A. senticosus flavonoids could reduce the level of MDA in the mouse serum and increase the levels of SOD, CAT, and GPx. Histopathology showed that the tissue pathological changes in the A. senticosus flavonoid group were significantly lower than those in the DSS group. The Western blot experiments showed that the antioxidant capacity of A. senticosus flavonoids was accomplished through the Nrf2 pathway. In conclusion, A. senticosus flavonoids can relieve oxidative stress in vivo and in vitro and protect cells or tissues from oxidative damage.

The Therapeutic Effect of Acanthopanax senticosus Components on Radiation-Induced Brain Injury Based on the Pharmacokinetics and Neurotransmitters

Acanthopanax senticosus (AS) is a medicinal and food homologous plant with many biological activities. In this research, we generated a brain injury model by ⁶⁰Co -γ ray radiation at 4 Gy, and gavaged adult mice with the extract with AS, Acanthopanax senticocus polysaccharides (ASPS), flavones, syringin and eleutheroside E (EE) to explore the therapeutic effect and metabolic characteristics of AS on the brain injury. Behavioral tests and pathological experiments showed that the AS prevented the irradiated mice from learning and memory ability impairment and protected the neurons of irradiated mice. Meanwhile, the functional components of AS increased the antioxidant activity of irradiated mice. Furthermore, we found the changes of neurotransmitters, especially in the EE and syringin groups. Finally, distribution and pharmacokinetic analysis of AS showed that the functional components, especially EE, could exert their therapeutic effects in brain of irradiated mice. This lays a theoretical foundation for the further research on the treatment of radiation-induced brain injury by AS.

A review of Acanthopanax senticosus (Rupr and Maxim.) harms: From ethnopharmacological use to modern application

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthopanax senticosus (AS), previously classified as Eleutherococcus senticosus, is one of the most commonly used herbs in the Chinese materia medica. However, there is currently no comprehensive review summarising advances in AS research. AS has been used as a functional food and in various preparations since ancient times, to invigorate the liver and kidneys, replenish vitality, strengthen the bones, stimulate appetite, and improve memory. It is widely used in countries such as China, Korea, Japan, and Russia, for specific pharmacologic effects, although it contains various chemical components that ensure its broad-spectrum effect. Its chemical constituents mainly include glycosides and flavonoids. Over the past several decades, researchers worldwide have conducted systematic investigations on this herb. AS has positive pharmacological effects on the cardiovascular, central nervous, and immune systems. Representative pathways stimulated by AS are related to neuroactive ligand-receptor interactions, cancer, and phosphatidylinositol 3 kinase/protein kinase B signalling. Importantly, AS is safe and exerts no significant adverse effects at normal doses.

AIM OF THE STUDY

To provide comprehensive insights into the ethnobotany, medicinal uses, chemical composition, pharmacological activity, and toxicology of AS to aid its future development and utilisation.

MATERIALS AND METHODS

Information about AS was collected from various sources, including classic books about Chinese herbal medicine and scientific databases including scientific journals, books, and pharmacopoeia. We discuss the ethnopharmacology of AS from 1965 to 2020 and summarise the knowledge of AS phytochemicals, pharmacological activity, quality control, and toxicology.

CONCLUSIONS

From the current literature, we conclude that AS is a promising dietary Chinese herb with various potential applications owing to its multiple therapeutic effects.