Polygalae radix (2017-19) & Cognitive Dysfunction


Polygalae radix is derived from Polygala tenuifolia Willd and is found typically as part of the Chinese herbal formulas Kai-xin-san or Bushen Tiansui. An extract of polygalae radix prevents cognitive deficit and neuron axon degeneration associated with amyloid plaque accumulation in a mouse model of AD although it does not influence the formation of plaque. It protects the area of growth at the tips of axons.1 Other extracts of kai-xin-san have been tested and some are found to increase both nerve growth factor (it regulates nerve growth) and brain-derived neurotrophic expression.2 These proteins control growth, stability, proliferation, and survival of nerve cells in the brain.

In a mouse model of Alzheimer's tenuifolin (a component of polygalae radix) was tested against nerve cell death and memory dysfunction. Tenuifolin reversed spatial learning and memory deficits, as well as nerve cell death in the hippocampus. It protected mitochondrial membranes and may be useful in AD therapies.3

1. Kuboyama T, Hirotsu K, Arai T, Yamasaki H, Tohda C. (2017). Polygalae Radix Extract Prevents Axonal Degeneration and Memory Deficits in a Transgenic Mouse Model of Alzheimer's Disease. Front Pharmacol. Nov 14;8:805.
2. Cao C, Xiao J, Liu M, Ge Z, Huang R, et al. (2018). Active components, derived from Kai-xin-san, a herbal formula, increase the expressions of neurotrophic factor NGF and BDNF on mouse astrocyte primary cultures via cAMP-dependent signaling pathway. J Ethnopharmacol. Oct 5;224:554-562
3. Wang L, Jin GF, Yu HH, Lu XH, Zou HZ, et al. (2019). Protective effects of tenuifolin isolated from Polygala tenuifolia Willd roots on neuronal apoptosis and learning and memory deficits in mice with Alzheimer's disease. Food Funct. Nov 1;10(11):7453-7460.