Polygala tenuifolia is an herb with potential nootropic properties. Unfortunately, there are very few human studies. Although their results are promising, the evidence is insufficient to support its effectiveness at improving memory in healthy people and cognitive function in the elderly. Animal studies show that this herb may effectively improve depression, anxiety, and sleep. Read on to learn about the other potential benefits of this plant.

What Is Polygala tenuifolia?

Polygala tenuifolia, also known as yuan zhi, is an herb. Its root is widely used in Chinese medicine to improve memory and combat forgetfulness and aging [1].

Polygala root contains many potentially neuroprotective and anti-inflammatory compounds, including:

• Tenuifolisides increase BDNF and suppress inflammatory cytokines (TNF-alpha, IL-1beta) and other inflammation-causing agents (NF-kB, PGE2, iNOs, COX2) [2, 3].
• 3,6-Disinapoylsucrose increases BDNF and activates CREB [4].
• Polygala saponins activate TrkB (the BDNF receptor) and prevent the decrease in NMDA receptors in aged animals [5, 6].

Snapshot

Proponents

• Preliminary research suggests it may improve memory in healthy people and cognitive function in elderly people
• Few mild adverse effects reported

Skeptics

• Insufficient evidence for all benefits
• Relatively unknown safety profile

Health Benefits

Insufficient Evidence for:

1) Improving Memory

In a clinical trial on 48 healthy people, Polygala tenuifolia root extract improved spatial and verbal memory. Those who received it also made fewer errors and scored better on a test measuring working memory [7].

Similarly, Polygala tenuifolia extract improved both spatial and non-spatial memory in aged mice [8].

It also improved short-term memory in rats with drug-induced memory impairment and mice poisoned with manganese [9, 10].

This supplement may improve memory by:

• Inhibiting the enzyme acetylcholinesterase (AChE), which reduces the breakdown of acetylcholine [11].
• Inhibiting MAO enzymes. This reduces the breakdown of dopamine,