Oxytropis falcate

Last Updated: November 18 2022

Oxytropis Falcate (Edaxia) is a herb deemed the 'King of Herbs' in Tibetan medicine, but despite its acclaim it is highly underresearched. Appeared to have potential potent painkilling effects and contains phenethylamines.

Oxytropis falcate is most often used for




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1.

Sources and Composition

1.1

Sources

Oxytropis falcate (of the family Leguminosae) is a herb used in Traditional Chinese Medicine where it has the name 'Edaxia' and used to treat inflammation, influenza, pain, bleeding and anthrax. It has been used in Tibetan medicine, where it is called “King of Herbs” and one of the “Three Anti-inflammatory Drug”.[1][2] It commonly grows in high altitudes (2700–4300m above sea level) in North Eastern and Southern Western China and due to this tends to grow mostly in either the Himilayas or at the Qinghai-Tibet Plateau.[3] Traditional usage of Oxytropis Falcate, usually in Tibet, suggests that spraying the dried powder of the roots over wounds accelerates healing and provides pain relief.[3]

The term 'Locoweed' is used to refer to plants of the Oxytropis family (although some plants of the Astragalus family also get included[4] and sometimes Swainsonia also gets called Locoweed[5]). These three genera all get called Locoweed due to having similar social renown, since the bioactive Swainsonine that is found in all genera (not yet identified in the species of Oxytropus known as Falcate but is present in ochrocephala[4]) can inhibit lysosomal α-mannosidase and mannosidase II enzymes and kill livestock that forage on 'Locoweeds'.[6][7][8]

Some studies also refer to similar historical usage when referring to an Oxytropus Falcata, suggesting the two species names are used interchangeably.[1]

A highly acclaimed herb for Tibetan medicine (King of Tibetan Medicine like Ganoderma Lucidum is to Chinese and Ashawgandha is to Indian). A species in the Oxytropus genera appears to be highly toxic to livestock that graze upon it

1.2

Composition

Oxytropis contains:

  • Oxytropine A-C (actually all structurally different)[4] and Oxytrofalcatin A-F (structurally related N-benzoylindole analogues)[4][5]
  • Falcatins A and B, two triterpenes[9] and two 'rare' sequesterpenes 3-methyl-5-(2,2,4-trimethylcyclohexanol-3-yl)pent-1-ene-3-ol and 3-methyl-5-(1,3,3-trimethyl-7-oxabicyclo{2.2.1}hept-2-yl)pent-1-en-3-ol[9]
  • 2′,4′-Dihydroxychalcone (DHC) is sometimes seen as the main active ingredient (despite not being named after the herb),[2] and 2′,4′,β-trihydroxy-dihydrochalcone is also found in this plant[3] as well as other chalcone structures[3][10]
  • N-Benzoyl-β-phenylethylamine[11] and (-)-N-Benzoyl-2-hydroxy-2-phenylethylamine[4][12]
  • N-formylbenzamide, 4-hydroxybenzamide, and N-formyl-p-hydroxybenzamide[5]
  • Rhamnetin, Rhamnocitrin,[1][3] and the latter's 3-O-beta-neohesperidoside.[11] Rhamnocitrin has also been found to be bound to 3-Hydroxy-3-methylglutarate group on its glycoside, and this compound (rhamnocitrin-3-O-{(S)-3-hydroxy-3-methylglutaryl-(1→3)}-{α-l-rhamnopyranosyl-(1→2)}-β-d-galactopyranoside) is referred to as Oxytroflavoside B.[1] Oxytropisoflavans A and B have been reported, and are structually different than the aforementioned[13]
  • Kaempferol (and many glycosides such as Robinin, Astrasikokioside I, and Mauritianin),[1][3] Quercetin, and Apigenin[4]
  • (6aR,11aR)-3,8-dihydroxy-9,10-dimethoxypterocarpan, propterol B, (3R)-(−)-isomucronulatol, and mucronulatol[13]
  • Chrysin[4], Genistin (the glycoside of one of the two Soy isoflavones)[4] and Daidzein (the other one)[13]
  • Melilotigenin B and C, initially from Melilotus officinalis and 24-hydroxy-11-deoxoglabrolide[9]
  • Pinocembrin,[11] Pinostrobin, and Liquirtigenin (an active component of Licorice)[4]
  • Naringenin,[14] Formononectin,[13][4] and Luteolin[4]
  • Dalbergin, (-)-Maackiain,[11] Sparteine, Lupanine, Thermopsine, and Anagyrine[4]
  • Pendulone, calycosin, 2'-hydroxybiochanin A, Pseudobaptigenin, Astraciceran, and (S)-(–)-Sakuranetin[13]
  • 3',4',5,7-4-hydroxy-flavanone[14]
  • 5,6-dihydroxy-3,7,3',4'-tetramethoxyflavonol and 5,6-dihydroxy-3,7,4'-trimethoxyflavonol[14]
  • β-sitosterol, Daucosterol, Stigmasterol, 7a-hydroxysitosterol, and 7-oxositosterol[14][15]

A cluster of standard flavanoid compounds with some unique ones (really, there is an astonishing variety of flavanoids here that need to be quantified), some structurally unique chalcone structures which are thought to be the active ingredients, and a confirmed phenethylamine content

Anti-oxidant properties in this plant appear to be mostly via the flavonoids, as the chalcones are weak in a DPPH assay.[3]

image

A very weird collection of interesting looking structures to be honest, even Oxytropine C appears to be structurally related to catecholamines (if broken to the top right of the left benzene ring)

2.

Pharmacology

2.1

Transdermal

When topically applied (Oxytropis Falcate ethanolic extract in 2% aqueous sodium hydroxide with a 5.5mg/kg application of DHC), the active ingredient of 2',4'-Dihydroxychalcone (DHC) appeared to be relatively quickly absorbed with a Cmax at 24.87+/-3.85ng/mL reaching a Tmax of 70.59+/-23.66 minutes.[2] This study noted a half-life of 155.06+/-23.58 minutes (similar to injections) and an AUC of 7196.8621+/-792.31ng/h/mL.[2] The absolute bioavailability of DHC via transdermal means appeared to be 16.93%[2] and may be enhanced three-fold if given via an ointment rather than solution.[16]

3.

Inflammation and Immunology

3.1

Analgesia

Topical application of Oxytropis Falcate is able to dose-dependently reduce the perception of pain in mice (assessed by acetic acid induced writhing) in a dose dependent manner reaching 56.67% at a topical dose of 90.6mg/kg Oxytropis (5.5mg/kg DHC), which outperformed the active control of Diclofenac emulgel (34.75%).[2] This pain reduction was noted in a hot-plate test, where dose-dependence was noted and the highest dose outperformed the active control at 30, 60, and 90 minutes of assessment.[2]

Appeared to be a fairly potent pain-killer according to the one study conducted on it

3.2

Edema

A study where edema was induced with topical xylene noted that pretreatment for 5 days with topical Oxytropis falcate was able to reduce edema in a dose-dependent manner from 4.16-66.03%, with the highest dose (90.6mg/kg Oxytropis conferring 5.5mg/kg DHC) outperforming the active control of Diclofenac emulgel at 39.48%.[2]

3.3

Interventions

In a mouse model of arthritis (complete Freund's adjuvant injections), topical administration of Oxytropis falcate (5.7-90.6mg/kg) was able to attenuate joint inflammation in a dose-dependent manner.[2]

Possible anti-inflammatory effects following topical administration

References
1.^Wang SS, Zhang XJ, Que S, Tu GZ, Wan D, Cheng W, Liang H, Ye J, Zhang QY3-Hydroxy-3-methylglutaryl flavonol glycosides from Oxytropis falcataJ Nat Prod.(2012 Jul 27)
6.^Stegelmeier BL, Molyneux RJ, Elbein AD, James LFThe lesions of locoweed (Astragalus mollissimus), swainsonine, and castanospermine in ratsVet Pathol.(1995 May)
8.^James LF, Panter KE, Gaffield W, Molyneux RJBiomedical applications of poisonous plant researchJ Agric Food Chem.(2004 Jun 2)
11.^Yao SY, Ma YB, Tang Y, Chen JJ, Zhang XMChemical constituents of Oxytropis falcateZhongguo Zhong Yao Za Zhi.(2008 Jun)
13.^Chen WH, Wang R, Shi YPFlavonoids in the poisonous plant Oxytropis falcataJ Nat Prod.(2010 Aug 27)
16.^Li WD, Chen ZP, Qu MM, Liu D, Xiao YY, Cai BCStudy on the pharmacokinetics Oxytropis falcate total flavonoids ointment in ratsZhong Yao Cai.(2011 Sep)