Kava, Piper methysticum, its six kavalactones, the flavokavains and pipermethystine, and how a move from cold water to ethanol and acetone extraction changed what reached the liver.

The episode reads the Institute's 2026 kava monograph. Kava is a sterile cultigen: it sets no viable seed, so every plant across Oceania for about 3,000 years has come from a stem cutting. The accepted name is Piper methysticum G.Forst.; material traded as Macropiper latifolium belongs to another species and is not kava. Vanuatu's Kava Act 2002 sorts the roughly 200 cultivars into noble, tudei and wichmannii groups and allows only noble kava for export and drinking. A common garden trial at the Waimanalo Research Farm in Hawaii grew two cultivars side by side for 3.4 years, and one carried about twice the kavalactones of the other. Strength follows the cultivar and the plant part; a Vanuatu origin speaks to legal standing and traceability.

On the clinical side, a Cochrane review of 11 trials and 645 people found a 5-point drop on the Hamilton anxiety scale, graded tier B, almost all of it from acetone or ethanol extracts such as WS 1490. Aqueous extracts gave mixed results in generalised anxiety disorder, including a 16-week Australian trial of 171 people that did not beat placebo, and Australian listed medicines may only use an aqueous extract of peeled root or rhizome, capped at 250 mg of kavalactones a day. The second half covers the 2000 to 2001 liver injury reports, a published Australian death, kava dermopathy in heavy traditional drinkers, four explanations for the liver cases (peelings, solvents, mould and tudei substitution), the three-month limit, pregnancy, alcohol, paracetamol and levodopa, six questions to put to a supplier, and a clonal crop in a changing climate.

In this episode: (00:00) Three thousand years of kava, then liver failure; (01:15) The Institute behind the monograph; (03:25) Piper methysticum, the intoxicating pepper; (04:21) A sterile clone kept alive by cuttings; (05:47) Peeled rootstock only; (06:30) G.Forst. or L.f.: a naming error in the trade; (08:55) Root scars, a fibrous fracture and a numb tongue; (10:30) Two hundred cultivars; (11:18) Vanuatu's Kava Act 2002: noble, tudei and wichmannii; (13:12) Rain, shade and three to five years in the ground; (14:53) The country-of-origin myth; (15:38) The Waimanalo common garden trial; (18:00) What a Vanuatu origin guarantees; (19:35) Six kavalactones; (20:28) Flavokavains and pipermethystine; (21:45) UHPLC and the chemotype code; (23:18) The kavain to flavokavain B ratio; (24:52) Cold water against ethanol and acetone; (26:20) Fifty times the flavokavains; (28:13) Liver cells in the dish; (29:42) The Cochrane review: 11 trials, 645 people; (31:46) Water extracts in generalised anxiety disorder; (33:16) The Australian irony: aqueous extracts only; (34:30) Trials that never named the chemotype; (35:55) The 2000 to 2001 liver reports; (37:07) An Australian death; (39:15) Pacific drinkers and kava dermopathy; (40:13) Four suspects: peelings, solvents, mould, tudei; (43:12) A perfect storm; (44:14) Australian limits: 250 mg, aqueous, peeled root; (45:41) Three months, pregnancy and alcohol; (46:30) Paracetamol and levodopa; (47:58) Six questions for a supplier; (51:23) A clone in a changing climate; (55:01) Closing.

Read more in the Institute's Journal: https://www.australian-pharmacognosy.org/pharmacopoeia/piper-methysticum/

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.

The Herbarium Hour, from the Australian Institute of Pharmacognosy, Cardwell, Queensland.

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.

Chapters00:00 A supplement, then a transplant list01:39 Why the Institute put this monograph together03:16 The plant in Appalachian woodland04:55 The rhizome, the drug and its old names06:32 Cimicifuga or Actaea: the 1998 revision09:44 Sheng ma and the shipping manifest11:21 Microscopy: clearing agents and lignified vessels12:59 Starch granules with a slit hilum14:37 Negative markers that condemn a batch16:12 Triterpene glycosides and the 1.0% limit17:48 Why the calibrant comes from liquorice19:25 HPLC, light scattering and twelve peaks21:00 Half a million pounds a year, almost all wild collected22:42 Yellow cohosh, and deliberate substitution24:20 The 2001 TGA survey: 35% were other species25:57 Cimifugin, the chemical dye pack27:37 How the TLC screen is run29:17 Twenty-five years on, and a new market survey30:57 The phytoestrogen theory32:35 Formononetin was never there34:13 Serotonin, opioid and dopamine pathways35:49 What the 40 mg extract trials show39:08 Liquid extracts at 20 to 35 times the trial dose42:24 Idiosyncratic liver injury and the Australian label45:37 Liver disease, pregnancy and lactation47:16 The blue cohosh combination case48:51 Hormone-dependent tumours and the observational data52:10 A DNA barcoding proposal for the Australian market53:46 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.

Andrographis paniculata, the king of bitters, its andrographolide diterpenoids, and the anaphylaxis signal that led the TGA to remove it from the ingredients allowed in Australian listed medicines on 17/09/2026.

The episode reads the Institute's 2026 monograph and literature review. Andrographis is a knee-high annual of the Acanthaceae from southern India and Sri Lanka, naturalised as a weed in parts of Queensland, with square stems, narrow hairless leaves and small white flowers marked with violet. The trade name green chiretta is shared with Swertia chirayita, a gentian with a different chemistry, so only the full binomial on the raw material identifies it. Edward John Waring's 1868 Pharmacopoeia of India listed it as a bitter tonic and doubted its credit, since his patients also got stronger remedies.

The second half follows the TGA safety review to 31/12/2025: 287 Australian anaphylaxis reports, 130 hospital admissions, 105 people given adrenaline and one death in June 2024. Of those reactions, 74% began within 30 minutes, over half the people had no allergy history, and 71% came on first use or after earlier uneventful use. Combination products with echinacea made up about 98% of supply. Single-ingredient andrographis was 0.14% of supply and 0.74% of cases, echinacea without andrographis drew 10 reports over the same period, and Thai VigiBase data showed the same signal for andrographis taken alone. Label warnings from 2020 did not bring reports down. The closing sections cover what the removal means for listed medicines and for practitioner-compounded supply, warfarin and immunosuppressants, pregnancy, who should stop or avoid it, and the signs of anaphylaxis with the first aid: call triple zero, lie the person flat, and give adrenaline if in doubt.

In this episode: (00:00) The medicine cabinet; (02:41) The Institute's sources; (04:58) From king of bitters to regulatory action; (05:27) A knee-high weed with square stems; (08:20) Many names, and the chiretta trap; (10:36) Traditional use across South Asia and China; (12:26) Waring's footnote, 1868; (14:39) What tradition can and cannot tell us; (16:09) Andrographis in Australian cold products; (17:41) Three different doses; (22:22) Does it shorten a cold?; (23:40) Tier B, and why; (25:51) COVID-19 trials in Thailand; (27:51) Ulcerative colitis, stopped for futility; (29:39) A modest benefit, summed up; (30:53) The TGA adverse event data; (31:55) What anaphylaxis does to the body; (33:05) 287 reports to December 2025; (34:19) Fast reactions in people with no allergy history; (36:42) How a first dose can react; (38:49) Was echinacea to blame?; (40:00) Supply data and single-herb products; (42:03) The Thai VigiBase signal; (43:36) Label warnings from 2020; (45:30) Why the labels failed; (48:52) Cofactors: anti-inflammatories, alcohol, exercise; (49:57) Removal from listed medicines, 17/09/2026; (51:48) The practitioner compounding exemption; (53:36) Screening, interactions and the first dose; (56:16) Is it worth prescribing?; (56:57) Check your cabinet; (58:00) Who should stop or avoid it; (59:41) Pregnancy and breastfeeding; (1:00:35) Signs of anaphylaxis; (1:02:05) First aid: triple zero, lie flat, adrenaline; (1:04:18) The arc of the story; (1:05:47) Closing thought.

Read more in the Institute's Journal: https://www.australian-pharmacognosy.org/pharmacopoeia/andrographis-paniculata/

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.

The Herbarium Hour, from the Australian Institute of Pharmacognosy, Cardwell, Queensland.