# Cycloastragenol Derivatives Improve Tyrosine Metabolism, Regulate TLR4/NF‐κB/TERT Signaling Pathways, and Inhibit MPTP Induced Neuroinflammation and PD Symptoms

## TL;DR

Cycloastragenol derivatives reduce Parkinson's disease symptoms by targeting inflammation and aging-related pathways, offering a new drug development strategy.

## Contribution

The study introduces a cycloastragenol derivative (R2) that improves anti-inflammatory and neuroprotective effects through structural optimization.

## Key findings

- Compound R2 improves motor dysfunction and reduces inflammation in a Parkinson's disease mouse model.
- R2 regulates tyrosine metabolism and the TLR4/NF-κB/TERT signaling pathway to combat PD progression.

## Abstract

Parkinson's disease (PD) is a neurodegenerative disease closely related to neuroinflammation and with obvious age characteristics. Existing therapeutic drugs have problems such as insufficient efficacy and side effects. Cycloastragenol (CAG) is a known natural telomerase activator, and previous studies have found that it has a good improvement effect on PD. As a lead compound, there is significant room for improvement in pharmacological activity. Therefore, we further explore safe and efficient small molecules for PD drug exploration through structural optimization.

We introduced carboxylic acid small molecules into the CAG structure and evaluated the pharmacological effects of the derivatives using a PD in vitro model and a neuroinflammatory model. The structure–activity relationship analysis was used to screen the derivatives with the best activity for subsequent in vivo animal experiments. Utilize metabolomics and subsequent validation experiments to elucidate the potential mechanisms by which the derivatives exert their effects.

We screened and obtained compound R2 from 29 derivatives, which can significantly enhance anti‐inflammatory activity and cell protection. In the MPTP induced PD mouse model, R2 can improve motor dysfunction, restore the number of TH positive neurons in the substantia nigra, and reduce inflammation levels in brain tissue and serum. Metabolomics analysis showed that R2 intervenes in PD progression by regulating the tyrosine metabolism pathway, and further validated the mechanism of compound R2 around the TLR4/NF‐κB/TERT signaling pathway. This study provides a new strategy for the development of anti PD drugs based on CAG, while expanding the potential application of carboxylic acid modification in natural product structure optimization.

This study focuses on the potential mechanism of CAG derivative R2 in treating PD through “inflammation‐aging” research. By inhibiting inflammation and restoring telomerase activity, it breaks the vicious cycle and provides new ideas for the treatment of PD, laying a foundation for the development of drugs using CAG for PD.

Cycloastragenol derivatives regulate the TLR4/NF‐κB/TERT signaling pathway and tyrosine metabolism, breaking the vicious cycle of “inflammation‐aging” and improving symptoms of Parkinson's disease. This study provides direction for the application of natural products in the development of PD drugs.