# Therapeutic potential of extracellular vesicles derived from Platycladus Orientalis leaf in treating anxiety, depression, and insomnia

## TL;DR

This study explores how extracellular vesicles from Platycladus orientalis leaf can treat anxiety, depression, and insomnia by regulating neurotransmitters and reducing inflammation.

## Contribution

The study introduces plant-derived extracellular vesicles as novel, low-immunogenic therapeutics for psychiatric disorders.

## Key findings

- P. orientalis EVs reduced anxiety-like behaviors and restored cognition in stressed mice.
- EVs improved sleep parameters and normalized neurotransmitter levels in insomnia models.
- EVs exhibited anti-inflammatory effects by reducing TNF-α and IL-6 while increasing TGF-β.

## Abstract

Extracellular vesicles (EVs) mediate intercellular communication by transferring bioactive molecules. While animal-derived EVs are well studied, plant-derived EVs (plant-EVs) are emerging as stable, low-immunogenic nanocarriers with therapeutic potential. Platycladus orientalis (L.) Franco, used in traditional medicine, contains neuroactive compounds. This study evaluated the effects of P. orientalis leaf-derived EVs in rodent models of anxiety, depression, and insomnia.

EVs were isolated by differential ultracentrifugation, characterized by electron microscopy and nanoparticle tracking analysis, and their bioactive components identified by GC -MS. Uptake was assessed in PC12 cells. Behavioral and biochemical effects were tested in mice subjected to chronic restraint stress (CRS), chronic unpredictable mild stress (CUMS), and para-chlorophenylalanine (PCPA)-induced insomnia. Key outcomes included social interaction, sucrose preference, Morris water maze performance, sleep parameters, neurotransmitter levels (5-HT, GABA), and inflammatory markers.

P. orientalis EVs exhibited bilayer vesicle morphology (∼100 nm) and contained abundant volatile compounds, particularly α-pinene. They were internalized by PC12 cells and reduced corticosterone-induced injury. In vivo, intranasal EV administration alleviated anxiety-like behaviors in CRS mice, restored sucrose preference and cognition in CUMS mice, and improved sleep onset and duration in PCPA-induced insomnia. Across models, EVs normalized serum and hippocampal 5-HT and GABA levels, reduced pro-inflammatory cytokines (TNF-α, IL-6), and increased TGF-β expression.

P. orientalis leaf-derived EVs exert significant anxiolytic, antidepressant, and soporific effects through multimodal mechanisms involving neurotransmitter regulation and anti-inflammatory activity. Intranasal administration offers an effective strategy to bypass the blood -brain barrier, supporting the translational potential of plant-EVs as novel therapeutics for psychiatric disorders.