Parts Used & Where Grown
Three similar plants are all called peony, and different parts are used in some cases. The bark of the root of Paeonia suffruticosa is called moutan or mu dan in China, where it naturally grows. Red peony root comes from wild harvested Paeonia lactiflora or Paeonia veitchii. White peony root comes from cultivated Paeonia lactiflora. The bark, red peony root, and white peony root all have somewhat different properties. Dried versus charred roots also have different properties. The color indicated does not refer to flower color. An important formula used in Chinese and Japanese herbal medicine called shakuyaku-kanzo-to contains white peony root and licorice root. The roots and flowers of Paeonia officinalis have been used in European herbal medicine. However, the German Commission E did not approve this plant for medicinal use.1
How It Works
Peony contains a unique glycoside called paeoniflorin. Proanthocyanidins, flavonoids, tannins, polysaccharides, and paeoniflorin are all considered to contribute to the medicinal activity of various forms of peony. Paeoniflorin’s major effect seems to be to calm nerves and alleviate spasm. One study has confirmed the efficacy of shakuyaku-kanzo-to (formula with peony and licorice) for relieving muscle cramps due to cirrhosis of the liver, diabetes, and dialysis.2 Shakuyaku-kanzo-to is approved by the Japanese Ministry of Health and Welfare for treatment of muscle cramps. Another Japanese formulation known as toki-shakuyaku-san combines peony root with dong quai and four other herbs and has been found to effectively reduce symptoms of cramping and pain associated with dysmenorrhea (painful menses).3
Paeoniflorin and peony extracts also enhance mental function in animal studies,4 suggesting a potential benefit for dementia. Human studies have not yet been conducted to confirm this theory.
Red peony root and moutan bark have both shown antioxidant activity in test tubes, likely due to the presence of paeoniflorin, proanthocyanidins, and flavonoids.5 Polysaccharides found in peony bark and root have shown an ability to stimulate immune cells in the test tube.6,7
Animal studies have found that red peony root, alone or in combination with other Chinese herbs, could help prevent liver damage due to various chemical toxins.8 A crude extract of red peony root was shown in a small, preliminary trial to reduce liver fibrosis in some patients with chronic viral hepatitis.9 Other case studies published in Chinese have found red peony root helpful for people with viral hepatitis.10
Crude red peony root extracts and combinations of these extracts with other Chinese herbs inhibit platelet aggregation, thrombosis, and excessive clotting in the test tube and in animals.11,12 A rabbit study found that peony was effective at lowering cholesterol levels in the aorta.13 A preliminary human study confirmed that peony could inhibit platelet clumping.14 This suggests that peony might be helpful for prevention of atherosclerosis. However, clinical studies are needed to confirm this effect.
One uncontrolled clinical trial reported that moutan bark could significantly lower blood pressure in people with hypertension.15
Peony shows some weak estrogen-like effects, acting like a very weak anti-estrogen, particularly as part of the formula shakuyaku-kanzo-to. In a preliminary study, this formula was shown to improve fertility in women affected by polycystic ovary syndrome.16