The Black Cohosh Liver Mystery
Black cohosh (Actaea racemosa, long filed as Cimicifuga racemosa), its triterpene glycosides actein and 23-epi-26-deoxyactein, and the liver injury warning Australian labels have to carry.
The episode works through the Institute's pre-publication monograph AIP-HP003. It starts with the plant in shaded eastern North American woodland and the knotted dark rhizome and roots that make up the drug. Then comes the naming problem: the 1998 move of Cimicifuga into Actaea left the European Medicines Agency, the World Health Organization and most older trials on one name while the TGA and manufacturers moved to the other, so a toxicology search on one spelling misses decades of case data. Asian pharmacopoeias use Rhizoma cimicifugae for different species altogether, which is how a shipment of sheng ma can clear paperwork as black cohosh.
A laboratory section explains how the powder is authenticated: lignified vessels with bordered pits, suberised cork fragments, starch granules of 3 to 15 micrometres with a slit-shaped hilum, and the negative markers the European Pharmacopoeia insists on, no stomata, no trichomes, no calcium oxalate. Potency runs on HPLC with light-scattering detection, twelve summed peaks against a minimum of 1.0% triterpene glycosides, calibrated against monoammonium glycyrrhizate from liquorice. The supply chain follows: about 500,000 pounds of root a year, roughly 97% wild collected, lookalikes such as Actaea podocarpa in the same ravines, cheaper Asian species substituted on purpose, and a 2001 TGA survey that found 35% of Australian retail products held other species. Cimifugin, absent from authentic North American material, is what a thin-layer chromatography screen hunts, down to about 5% adulteration.
Chapters
00:00 A supplement, then a transplant list
01:39 Why the Institute put this monograph together
03:16 The plant in Appalachian woodland
04:55 The rhizome, the drug and its old names
06:32 Cimicifuga or Actaea: the 1998 revision
09:44 Sheng ma and the shipping manifest
11:21 Microscopy: clearing agents and lignified vessels
12:59 Starch granules with a slit hilum
14:37 Negative markers that condemn a batch
16:12 Triterpene glycosides and the 1.0% limit
17:48 Why the calibrant comes from liquorice
19:25 HPLC, light scattering and twelve peaks
21:00 Half a million pounds a year, almost all wild collected
22:42 Yellow cohosh, and deliberate substitution
24:20 The 2001 TGA survey: 35% were other species
25:57 Cimifugin, the chemical dye pack
27:37 How the TLC screen is run
29:17 Twenty-five years on, and a new market survey
30:57 The phytoestrogen theory
32:35 Formononetin was never there
34:13 Serotonin, opioid and dopamine pathways
35:49 What the 40 mg extract trials show
39:08 Liquid extracts at 20 to 35 times the trial dose
42:24 Idiosyncratic liver injury and the Australian label
45:37 Liver disease, pregnancy and lactation
47:16 The blue cohosh combination case
48:51 Hormone-dependent tumours and the observational data
52:10 A DNA barcoding proposal for the Australian market
53:46 Closing thought
More from the Institute's Journal: https://www.australian-pharmacognosy.org/pharmacopoeia/actaea-racemosa/
Nothing in this episode is a prescription or a dose. If you want to use a herb, consult a degree-qualified herbalist with competencies and adequate training in pharmacognosy.
Dr Luke Iggulden, Chief Scientific Officer, made the episode from the Institute's Journal and monograph material. Jesse Kirby, Head of Community Outreach, wrote the show notes and chapters from the episode transcript. Jesse Kirby scheduled the release.
Australian Institute of Pharmacognosy, Cardwell, Queensland.