Plant Profiler

Agrimony (Agrimonia eupatoria)


Agrimonia eupatoria
Synonyms / Common Names / Related Terms
Agrimonia, Agrimonia asiatica, Agrimonia eupatoria L., Agrimonia parviflora, Agrimonia pilosa Ledeb, Agrimonia striata, Agrimony eupatoria L., Agrimony eupatoria, Agrimonia procera, Ackerkraut, Agrimoniae herba, Agrimonia, agrimony, Church Steeples, cockeburr, cocklebur, common agrimony, fragrant agrimony, Funffing, Funffingerkraut, Herba eupatoriae, herbe d'aigremoine, herbe de saint-guillaume, liverwort, longyacao, odermenning, philanthropos, Potentilla, roadside rosaceae, sticklewort, stickwort, woodland groovebur.

Note: There are other plants, which are not related botanically to agrimony, but are given a similar name by older herbalists due to similarities in properties. These include the common hemp agrimony (common Dutch agrimony, Eupatorium aquaticum mas, Eupatorium cannabinum) and the water agrimony (bastard agrimony, bastard hemp, Bidens tripartita, trifid bur-marigold).

Mechanism of Action

Pharmacology:

  • Constituents: There are approximately 350 species of aconite. Generally, the alkaloids aconitine, hypaconitine, mesaconitine, and jesaconitine have the strongest pharmacologic and toxic effects while their derivatives are weaker and less toxic. Many reports support aconite's cardiovascular effects of tachycardia and arrhythmias.
  • Anabolic effects: Aconite alkaloids, in particular mesaconitine, accelerate liver RNA synthesis mainly by the increase of RNA polymerase in mouse livers suggesting that aconite has anabolic activity.5
  • Analgesic effects: Based on animal experiments, mesaconitine's analgesic activity is mediated by central noradrenergic pathways.5,6
  • Anti-inflammatory effects: Alkaloids from methanol extracts of crude Aconitum carmichaeli roots inhibited acute inflammation but were not effective against chronic inflammation in animal models. Inhibitory effects of aconitines when induced by histamine appears in decreasing order, aconitine > hypaconitine > mesaconitine. Their benzoylaconine analogs were effective in acute inflammation at higher doses. Their anti-inflammatory effects appears in decreasing order, benzoylmesaconine > benzoylaconine > benzoyhypaconine.7 Based on studies of inflammation models in animals, mesaconitine has CNS-mediated anti-inflammatory effects. It appears to inhibit inflammation at early stages. Mesaconitine did not inhibit prostaglandin synthesis and the adrenal system was not involved in anti-inflammatory effects.8
  • Antipyretic effects: Mesaconitine and ignavine demonstrated hypothermic effects; ignavine being effective only at high doses.9
  • Cardiovascular effects: Aconite administered intraperitoneally produced bradycardia in mice.10 Results of this experiment suggest that the anterior hypothalamus and surrounding muscarinic receptors are involved in the transmission of aconite-induced bradycardia. It was also found that aconitine increased cortical acetylcholine release, but this effect was not mediated by central muscarinic receptors. Acetylcholine is not involved in aconitine induced bradycardia. The action was inhibited by propranolol signifying that higenamine has calcium agnoistic effects.
  • Intracerebroventricular injection of aconitine produced tachycardia and hypertension in cats.11 Pretreatment with practolol or propranolol inhibited the tachycardia. Reserpine decreased tachycardia but not hypertension. These results suggest that aconitine's tachycardic effects are mediated by central beta-adrenergic receptors, and its hypertensive effects are because of central stimulation that causes peripheral vasoconstriction.
  • Higenamine, a component of the aconite root, had concentration-dependent positive inotropic effects in the papillary muscles of guinea pigs.12
  • Aconitine injections (0.03-10mcg) in the locus coeruleus in rats resulted bradycardia or tachycardia, arrhythmias, and hypertension.13 High doses had positive chronotropic effects. Low doses variously had positive or negative chronotropic effects. These effects were blocked by phentolamine and 2-bromo-lysergic acid diethylamide, a serotonin antagonist; atropine had no effect. Aconitine's cardiovascular effects may be mediated by alpha-adrenergic and/or serotonergic pathways.
  • Aconitine accelerates its spontaneous slow depolarization, and produces extremely rapid tachycardia, flutter and fibrillation in animals.14 Aconitine-induced fibrillation might be contributed to the formation of local blocks and ectopic pacemakers.15
  • Central nervous system (CNS) effects: Mesaconitine inhibited motor coordination and motor activity and demonstrated weak sedative effects in animal models. Ignavine displayed no sedative effects.9
  • Endocrine effects: Based on animal study, various root-derived aconitans reduced plasma glucose levels in a dose-dependent manner.16
  • Immunological effects: Aconitine stimulates the response of IFN-gamma-activated expression of Ia antigen by macrophages by increasing plasma corticosterone levels.17 Aconitum carmichaeli increases the secretion of interleukin-1b, interleukin-6, and tumor necrosis factor-alpha in human mononuclear cells (secondary source).
  • Neuomuscular blockade effects: Various alkaloids in processed aconite displayed neuromuscular blocking effects in isolated mouse phrenic nerve-diaphragm muscle preparations. Hypaconitine effects were four times stronger than aconitine and mesaconitine and were one-third to one-sixth as toxic. Coryneine, lipodeoxyaconitine, and lipohypaconitine had weaker effects; and lipoaconitine, higenamine, kobusine, benzoylmesaconine, and chasamine were not effective. It is suggested that aconitine's mechanism of action is blocking sodium channels in nerve membranes. Hypaconitine's mechanism of action was not determined.18

Pharmacodynamics/Kinetics:

  • Absorption: Aconitine is absorbed by the esophagus and stomach of a rat with the ability of the esophagus to absorb aconitine being stronger than that of the stomach.3
  • Distribution: Autopsy results after homicidal aconite poisoning detected jesacontine in the vomitus, stomach contents, plasma, and urine at concentrations of 32.2mcg/mL, 5.48mcg/mL, 0.433mcg/mL, and 1.07mcg/mL, respectively.4
  • Metabolism: Aconite is metabolized in the liver. The metabolism of aconite and its alkaloids has not been concluded in humans. De-esterification at C-8 and C-14 by esterase and N or O dealklyation by cytochrome P450 enzymes suggests possible pathways for the diesterditerpene-type alkaloids such as aconitine, mesaconitine, and hypaconitine.2 Aconitine is hydrolyzed at the C-8 group to benzoylaconine and at the C-8 and C-14 groups into aconine. Mesaconitine is hydrolyzed at the C-8 group to benzoylmesaconine and at the C-8 and C-14 groups to mesaconine. Hypaconitine is hydrolyzed at the C-8 group to benzoylhypaconine and at the C-8 and C-14 groups to hypaconine. These hydrolysis products are less toxic.
  • Elimination: Aconitum alkaloids aconitine, mesaconitine, and hypaconitine and their metabolites were detected in the urine 6 days after ingestion. It is suggested these alkaloids are excreted in a time-dependent manner.2
  • Because of aconite's lipid solubility and molecular size of 645.7 kilodaltons, hemodialysis, peritoneal dialysis, hemoperfusion and hemofiltration are unlikely to be effective in enhancing elimination.1

References
  1. Park EJ, Oh H, Kang TH, et al. An isocoumarin with hepatoprotective activity in Hep G2 and primary hepatocytes from Agrimonia pilosa. Arch Pharm Res 2004;27(9):944-946. 15473665
  2. Miyamoto K, Kishi N, Koshiura R. Antitumor effect of agrimoniin, a tannin of Agrimonia pilosa Ledeb., on transplantable rodent tumors. Jpn J Pharmacol 1987;43(2):187-195. 3573425
  3. Swanston-Flatt SK, Day C, Bailey CJ, et al. Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice. Diabetologia 1990;33(8):462-464. 2210118
  4. Gray AM, Flatt PR. Actions of the traditional anti-diabetic plant, Agrimony eupatoria (agrimony): effects on hyperglycaemia, cellular glucose metabolism and insulin secretion. Br J Nutr 1998;80(1):109-114. 9797650
  5. Willhite LA, O'Connell MB. Urogenital atrophy: prevention and treatment. Pharmacotherapy 2001;21(4):464-480. 11310520
  6. Li Y, Ooi LS, Wang H, et al. Antiviral activities of medicinal herbs traditionally used in southern mainland China. Phytother Res 2004;18(9):718-722. 15478204
  7. Ivanova D, Gerova D, Chervenkov T. Polyphenols and antioxidant capacity of Bulgarian medicinal plants. J Ethnopharmacol 2005;96(1-2):145-150.
  8. Copland A, Nahar L, Tomlinson CT, et al. Antibacterial and free radical scavenging activity of the seeds of Agrimonia eupatoria. Fitoterapia 2003;74(1-2):133-135. 12628408
  9. Gao K, Zhou L, Chen J. Experimental study on decoctum Agrimonia pilosa Ledeb-induced apoptosis in HL-60 cells in vitro. Zhong Yao Cai 2000;23(9):561-562.




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