Polygalae Radix: A review of its traditional uses, phytochemistry, pharmacology, toxicology, and pharmacokinetics

Polygalae Radix (Polygalaceae), the dried root of Polygala tenuifolia Willd. and Polygala sibirica L., has been widely used as a medicine for improving cognitive function. In China, Polygalae Radix has been widely used in the treatment of insomnia, forgetfulness, depression, cough, palpitation, and other diseases. More than 140 compounds have been isolated from Polygalae Radix, including saponins, xanthones, oligosaccharide esters, and so on. The compounds and extracts isolated from Polygalae Radix possess wide-ranging pharmacological activities, such as neuroprotective, antidepressant, hypnotic-sedative, anti-inflammatory, antiviral, antitumor, antioxidant, antiaging, and antiarrhythmic effects, among others. The clinical practice of traditional Chinese medicine has proved that raw Polygalae Radix can irritate the throat. Modern studies have found that raw Polygalae Radix exhibits a certain degree of toxicity to the gastrointestinal tract after long-term use or excessive doses and that its main toxic components are saponins. Thus, Polygalae Radix is usually processed, and/or combined with other herbs to reduce gastrointestinal irritation. This review investigated the pharmacokinetics of Polygalae Radix. Future research perspectives and the existing problems of Polygalae Radix were also discussed. This review can broaden the understanding regarding Polygalae Radix and provide references for further research.