Polygala Tenuifolia
Polygala tenuifolia
Also known as: Yuan Zhi, Chinese Senega, Thin-leaf Milkwort
Overview
One of the 50 fundamental herbs in traditional Chinese medicine. In animal and cell studies, Polygala raises BDNF levels in brain tissue. Human evidence is much thinner: two small 2009 trials of one proprietary extract (BT-11) found modest gains on some memory tests versus placebo, and they have not been independently replicated. No human study has measured BDNF.
Proposed mechanism
Tenuifolin, the main saponin in Polygala tenuifolia root, raises BDNF/TrkB signaling in the hippocampus in rodent stress and sleep-deprivation studies. Cholinesterase effects are compound-specific: onjisaponin B inhibits acetylcholinesterase in vitro, direct testing found tenuifolin does not, and the whole root extract is only a weak inhibitor. In preclinical Alzheimer's models, onjisaponin B reduces amyloid-beta by promoting APP degradation, and tenuifolin does so by lowering BACE1 expression in cell culture. All of this is animal and cell-line work — no TBI model and no human data exist for any of these mechanisms.
Mechanisms describe how researchers think a compound may act, often from laboratory work — a proposed mechanism is not proof of a clinical effect in people.
Traditional & studied uses
Related pathways
Pathway tags are a research aid for browsing the glossary — they are not a claim that this ingredient treats any condition.