Mu Dan Pi

The marker compound and the officially assayed active of this drug, and the reason Mu Dan Pi smells and tastes as it does, including the slight numbness on the tongue of good material. It selectively inhibited collagen-induced platelet aggregation and collagen-induced thromboxane B2 formation in rabbit platelets while barely affecting arachidonate-, thrombin- or A23187-induced aggregation, and it is rapidly absorbed, extensively metabolised and widely distributed without tissue accumulation after oral dosing in rats. Note that paeonol, not paeoniflorin, is the marker for this drug; paeoniflorin belongs to the Paeonia lactiflora roots Chi Shao and Bai Shao.

The glycosidic reservoir of paeonol in the root bark. They are largely inactive as given and are hydrolysed to release the aglycone, so drying and storage conditions that shift the glycoside-to-aglycone ratio change the assayed paeonol content of a batch.

Paeonol glycosides named for and characteristic of Paeonia suffruticosa. Their presence is a chemical point of difference from the Paeonia lactiflora root drugs.

Present in Moutan cortex but at far lower levels than in the Paeonia lactiflora root drugs, and it is not the officially assayed active here. Paeoniflorin obtained from P. suffruticosa selectively inhibited shear-stress-induced platelet aggregation without affecting agonist-induced aggregation, and was antithrombotic in vivo without prolonging bleeding time. This is not a reason to read the Total Glucosides of Paeony clinical literature onto Mu Dan Pi: that material is prepared from Paeonia lactiflora root, a different drug.

Paeoniflorin analogues consistently found among the predominant compounds of Moutan cortex extracts. Oxypaeoniflorin is one of the constituents identified as an active in network and pharmacokinetic analyses of the drug in blood-heat and blood-stasis models.

Isolated from Paeonia suffruticosa and shown to inhibit protein disulfide isomerase, a thiol isomerase required on the platelet surface for integrin activation and thrombus formation, with antithrombotic activity following. This is a distinct antithrombotic mechanism from paeonol's thromboxane effect and adds to the bleeding-risk picture for the whole drug.

Named with paeonol and paeoniflorin as one of the three compounds carrying most of the activity of the raw material. As a polyphenol of this size it also binds proteins and alkaloids in the gut, which is the usual basis for the general caution about taking tannin-rich decoctions at the same time as oral drugs.

Consistently among the predominant compounds of Moutan cortex extracts and one of the three analytes in the standard reversed-phase HPLC assay used in Chinese quality work alongside paeoniflorin and paeonol.

Isolated from the root bark together with paeonidanin, paeoniflorigenone, 2,5-dihydroxy-4-methoxyacetophenone, paeonol and gallic acid. It contributes to the total phenolic content of the drug, which has been measured across extracts at roughly 64 to 113 mg gallic acid equivalents per gram of extract.

The earliest record of Mu Dan. It gives the drug for alternating cold and heat, for wind-stroke with convulsion, tetany, fright epilepsy and evil qi, for dispersing hardened concretions and static blood lodged in the intestines and stomach, for settling the five viscera, and for treating welling abscesses and sores. Both halves of the modern profile, cooling the blood and moving static blood, are already present.

Adds seasonal-qi headache, guest heat, the five taxations with taxation qi, headache and lumbar pain, wind lockjaw, and withdrawal disease to the indications.

Records the drug as dispelling evil qi, freeing the interstices and blood vessels, expelling pus, freeing the menses, dispersing static blood from knocks and falls, knitting sinew and bone, dispelling wind impediment, and bringing down the fetus and placenta. That last clause is the classical basis for the pregnancy contraindication.

Li Shizhen places Dan Pi as treating hidden fire in the blood aspect of the four channels hand and foot shao yin and jue yin, harmonising, engendering and cooling the blood, and dispelling vexation heat. He also warns that the red-flowered plant drains while the white-flowered one supplements, and complains that few practitioners distinguish them, an early statement of exactly the sourcing problem this drug still has.