Du Huo

Du Huo - Angelica pubescentis
		Professional Data

Pin Yin
Du Huo

Latin
Radix Angelicae Pubescentis

Introduction

Angelica is a plant genus often used in traditional Chinese medicine. Officially listed in the Chinese Pharmacopoeia are three items:
Radix Angelicae dahuricae, is the dry root of Angelica dahurica (Fisch. ex Hoffm.) Benth. et Hook f. or A. dahurica var. formosana (Boiss.) Shan et Yuan (Apiaceae) collected between summer and fall when the leaves have turned yellow. It is used as an antipyretic and analgesic for cold, headache, and toothache.
Radix Angelicae sinensis, is the dry root of A. sinensis (Oliv.) Diels collected in late summer. It has been used as an analgesic in treatment of menstrual disorders, menorrhalgia, and rheumatalgia.
Radix Angelicae pubescentis, is the dry root of A. pubescens Maxim. f. biserrata Shan et Yuan (Fam. Umbelliferae). The drug is collected in late fall or early spring. It has been used as an analgesic and antirheumatic agent.
A. Pubescens is derived from the root and rhizome of the following plants of the families Umbelliferae and Araliaceae: Angelica pubescens Maxim. f. biserrata Shan et Yuan A. pubescens Maxim., A. dahurica (Fisch. ex Hoffm.) Benth. et Hook. f. ex Fianch et Sav., A. prophyrocaulis Nakai et Kitag., Heracleum hemsleyanum Diels, H. lanatum Michx., and Aralia cordata Thunb. There are a few other species from the genera Angelica, Heracleum and Aralia that are also used as sources of A. Pubescens in some localities in China.

Western medical

Antirheumatic, diaphoretic, discutient and analgesic actions. Traditionally used in the treatment of rheumatism, heaviness of the lower back and knees and arthritic conditions with associated limb contracture. Indicated for headache, dizziness, visual disturbances, rheumatism and numbness in the extremities caused by exposure to dampness.

Eastern medical

Pattern: To dispel wind and dampness.
Properties: Pungent, bitter, warm.
Channels entered: Kidney and urinary bladder.

Chemical constituents

A. pubescens contains a number of coumarin and furocoumarin derivatives, some of which were also found in A. dahurica. Hata and Kozawa have reported the isolation of osthol, bergapten, glabralactone, and angelol, from the root of A. pubescens. Kozawa et al. have also reported isolation of psoralen, xanthotoxin, isopimpinellin, byakangelicin, coumurrayin, 7-methoxy-8-senecioylcoumarin, scopoletin, and two prenylcoumarins structurally elucidated as 8-(3-hydroxyisovaleroyl)-5,7-dimethoxycoumarin and 5-isopentenyloxy-7-methoxy-8-senecioylcoumarin.
The structure of angelol (angelol A) was the focus of several studies. Baba et al. reported the isolation of some new angelol type prenylcoumarins, angelols B-H, together with previously known angelol A. The structures of these compounds were determined on the basis of spectral and chemical evidence. Angelol A and B; angelol C and F; and angelol D, G. and H are stereoisomers.
Chen et al. have isolated osthol, osthenol, bergapten, and the furo-(2,3)-benzopyran-2one derivatives columbianadin, columbianetin, and columbianetin acetate from the root of A. pubescens and A. pubescens f. biserrata.
The root of A. pubescens contains angelol, angelicone (glabralactone), bergapten, osthol, umbelliferone, scopoletin, angelic acid, tiglic acid, palmitic acid, flavonoids, and small amounts of volatile oil.
From the fruits of A. pubescens, nine coumarins were isolated and identifled as osthol, byakangelicin, byakangelicol, oxypeucedanin, umbelliferone, umbelliprenin imperatorin, neobyakangelicol, and sec-O-acetylbyakangelicin.

Pharmacological actions

Analgesic, Sedative, and Anti-inflammatory Effects

A. pubescens had antiinflammatory and analgesic effects on rat hind paw edema induced by carregeenan and on mouse writhing induced by acetic acid. The active principle was separated and identified as osthol.

In the hot plate experiment with mice, injection of the A. pubescens decoction 2 g/kg IP markedly prolonged the reaction time of the animals to pain, indicating a strong analgesic effect. Sedation and hypnosis were achieved with the fluidextract of the A. pubescens decoction intragastrically or intraperitoneally administered to mice or rats. Subcutaneous injection of the A. pubescens extract to frogs prevented convulsion due to strychnine, but not death associated with the latter.

Effects on the Cardiovascular System and Respiration

Intravenous injection of the tincture or decoction of A. pubescens to anesthetized dogs produced a significant hypotensive effect of short duration. Bilateral vagotomy did not modify the hypotensive effect but atropine could either partially or completely block it.

Perfusion of the A. pubescens decoction into the frog hind limb vessels caused vasoconstriction dose-dependently. Byak-angelicin, isopimpinellin, and 5-methoxy-S-hydroxypsoralen had a coronary dilatory action similar to but weaker than that of khellin. The potency of these agents was rated as follows: isopimpinellin > byak-angelicin > 5-methoxy-8-hydroxypsoralen. The aminoethyl derivatives of angelicin had adrenergic blocking effect.

Intravenous injection of the extract stimulated respiration, making it deeper and faster; the action was not weakened by procaine blockade of the vascular chemoreceptors.

Spasmolytic Effect

Bergapten, xanthotoxin, isopimpinellin, and alloisoimperatorin exerted a significant spasmolytic action on the rabbit ileum. Isopimpinellin, pimpinellin, and angelicin conspicuously antagonized barium chloride-induced spasm of the rat duodenal segment. Scopoletin relieved estrogen- or barium chloride-induced spasm of the rat uterus in vivo or in vitro, the ED50 was 0.09 mg/kg.

Antibacterial Effect

Escherichia coli, Shigella dysenteriae, Proteus vulgaris, Salmonella typhi, Pseudomonas aeruginosa, Vibrio cholerae, and Mycobacterium tuberculosis var. hominis were found to be susceptible to the decoction of A. dahurica. The MIC of the A. pubescens decoction against Mycobacterium tuberculosis in vitro was determined to be 1:100. The MIC of xanthotoxin against Mycobacterium tuberculosis var. hominis H37RV was 100 bg/ml. Umbelliferone was a potent inhibitor of Brucella organisms, the MIC being 1:2500. The furanocoumarins such as xanthotoxin generally had no significant antibacterial activity; however, when exposed to light together with Staphylpcoccus aureus, and Escherichia coli, they produced a photosensitizing effect which killed the bacteria.

Miscellaneous Actions

The furanocoumarins have an anti-gastric ulcer action. Experiments with rats showed that bergapten and pimpinellin afforded reasonable protection against experimental gastric ulcer, whereas isopimpinellin and xanthotoxin were weak. Breast cancer in rats caused by chemicals was apparently inhibited by scopoletin; in contrast, umbelliferone was ineffective. Xanthotoxin and bergapten were lethal to Ehrlich ascites carcinoma cells. In addition, A. Pubescens contracted the isolated abdominal straight muscle of frogs.

Clinical Studies

Rheumatic Syndrome

A. pubescens is often used in compound formulae to treat rheumatic syndrome due to "wind, cold, and damp pathogenic factors"-. A volatile oil injection prepared from the plant was used in 112 cases of soft tissue damage with a marked effective rate of 76.5%; pain was markedly reduced, swelling subsided, and functions recovered.

Vitiligo

Along with phototherapy, xanthotoxin 20 mg (adult) may be given by mouth once daily. This agent can also be applied locally to the skin.

Chronic Bronchitis

Antitussive and antiasthmatic effects were achieved in 422 cases treated with the A. pubescens decoction; 6.9% had marked effects while 66.8% showed some response.

References

Except those noted, all references come from Weng Weiliang, et al., Clinical Chinese materia medica, Henan Science & Technology Press, 1998