Herbal Research

Bai Zhi

RADIX ANGELICAE DAHURICAE (DAHURIAN ANGELICA ROOT)

Bai Zhi is the dried root of Angelica dahurica (Fisch. ex Hoffm.) Bentli. et Hook. f. or Angelica dahurica (Fisch. ex Hoffm.) Benth. et Hook. f. var. formosana (Boiss.) Shan et Yuan (Umbelliferae). A. dahurica f. grows wild in northeastern China on river banks, along streams and among rocky scrub. It is cultivated in the provinces of Sichuan, Hebei, Henan, Hubei, Hunan, Anhui and Shanxi. A. dahurica f. var. formosana can be found growing wild in Zhejiang and Taiwan. It is now cultivated in Zhejiang and Jiangsu. The herb is rarely gathered wild, most of it coming from cultivated plants in Sichuan and Zhejiang. It is collected between summer and autumn when the leaves have turned yellow, and is dried in the sun or at a low temperature.

CHEMISTRY

A series of coumarin and furocoumarin compounds were isolated from the root of A. dahurica var. formosana. Coumarin constituents are coumarin, scopoletin, 7-demethyl-suberosin, 6-methoxy-7-(3-methyl-2-butenyloxy) coumarmn and cedrelopsin1-3. Furocournarin constituents include psoralen, angelicin, bergapten, imperatorin, isoimperatorin, alloisoimperatorin, phellopterin, oxypeucedanin hydrate, byakangelicin, byakangelicol, anhydrobyakangelicin, tert-O-methylbyakangelicin, sec-O-acetylbyakangelicin, senbyakangelicol, 5-(2-hydroxy-3-methoxy-3-methyl-butoxy) psoralen, marmesin, xanthotoxin and neobyakangelicol1-9. >From the root of A. dahurica five coumarin glycosides nodakenin, 3'-hydroxymarmesinin, tert-O-b-D-glucopyranosyl byakangelicin, sec-O-b-D-glucopyranosyl bradykinin and scopolin, together with adenosine have been isolated10.
Stigmasterol, sitosterol and some lactones such as b-angelica lactone, 2-hydroxy-3,4-dimethyl-2-buten-4-olide, c-nona1actone and c-decalactone were also identified 2'9-12.

PHARMACOLOGY

Antihistiminic Effect

The ether or acetyl acetate extract of the herb at an intraperitoneal dose of 100 mg/kg inhibited compound 40/80-induced histamine elevation in mouse peritoneal cavity fluids. Bergapten, oxypeucedanin hydrate and byakangelicin were isolated as the active constituents from the extracts. They significantly inhibited compound 40/80-induced histamine elevation at an intraperitoneal dose of 25 mg/kg in mice13.

Endocrine Effect

Furocoumarins oxypeucedanin, bergapten, xanthotoxin, imperatorin and phellopterin activated adrenaline-induced lipolysis in experiments to determine the effects of the coumarins on the actions of adrenaline, ACTH and insulin in fat cells isolated from rats. Oxypeucedanin hydrate, imperatorin and phellopterin also activated ACTH-induced lipolysis, whereas the furocoumarins byakangelicin, neobyakangelicol and isopimpinellin strongly inhibited insulin-stimulated lipogenesis. Therefore, the root of A. dahurica activates lipolytic hormones and selectively inhibits antilipolytic hormones14.

Photochemical Activity

Oral administration of psoralen derivatives, especially 5-methoxy- and 8-methoxypsoralen in combination with photochemotherapy using long wave UV radiation (>320 nm) has been used to treat15,16. Psoralen and angelicin derivatives are bifunctional nucleic acid photoreagents which, upon irradiation with long wave UV light form mono- or diadducts with pyrimidine bases in DNA and RNA17'18. A direct correlation between the phototoxicity of psoralen derivatives, their induction of DNA interstrand crosslinks and inhibition of DNA synthesis was observed19.

Effect on Aldose Reductase and Galactosemic Cataract Formation

At 100 jig/ml the ether extract of the herb inhibited bovine lens aldose reductase activity by 100% in vitro. Byakangelicin and methyl byakangelicin were isolated as potential aldose reductase inhibitors, their IC50 values being 6.2 8M and 2.8 3M, respectively. Galactosemic cataract formation in rats treated with 40 g/kg of galactose was blocked almost completely throughout the experimental periods up to 44 days by intraperitoneal administration of byakangelicin at 50 mg/kg. In coincidence with the inhibitory action on cataract formation, the galactitol accumulation in rats treated with byakangelicin was found markedly prevented by approximately 80.5% compared to those of the control. These results indicated that byakangelicin has high potential as a clinically useful drug which prevents and/or improves sugar cataract as well as diabetic complications²⁰.

FUNCTIONS AND APPLICATIONS

Bai Zhi has a pungent taste and a warm property, acting on the lung, stomach and large intestine channels. It has the functions of:

(i) dispelling wind and relieving pain, used in headache, particularly pain in the forehead, toothache and stuffed nose in colds;
(ii) subduing swelling and promoting pus discharge, used in swelling and pain of sores and wounds; and
(iii) resolving damp and stopping leukorrhagia, used in excessive leukorrhea.

DOSAGE

3-9g.

SIDE EFFECTS AND TOXICITY

Mutagenic activity of psoralen derivatives after photoactivation was reported²¹.

REFERENCES

1. Saiki, Y., Morinaga, K., Okegawa, 0., Sakai, S., Amaya, Y., Ueno, A., etal. (1971) Coumarins of the roots of Angelica dahurica. Yakugaku Zasshi, 91, 1313-1316.
2. Zang, H.Q., Yuan, C.Q., Chen, GY., Ding, Y.M., Chen, S.Q., Deng, Y.Q. (1980) Study on the chemical constituents of the root of Angelico dahurica var. farmasana. Chinese Pharmaceutical Bulletin, 15, 2-4.
3. Kozawa, M., Baba, K., Okuda, K., Fukumoto, T., Hata, K. (1981) Studies on chemical components of Bai Zhi" (Suppli). On coumarins from Japanese Bai Zhi". Shoyakugaku Zasshi, 35, 90-95.
4. Hata, K., Kozawa, M., Yen, KY. (1963) Pharmacognostical studies on umbelliferous plants. XIX. Chinese drug hyakushi. 4. Coumarins of the roots of Angelica dahurica var. dahurica and A. dahurica var. paichi. Yakugaku Zasshi, 83, 606-610.
5. Hata, K., Kozawa, M., Yen, K.Y., Kimura, Y. (1963) Pharmacognostical studies on umbelliferous plants. XX. Chinese drug byakushi. 5. Coumarins of the roots of Angelicafarmasana and A. anamala. Yakugaku Zasshi, 83, 611-614.
6. Fujiwara, H., Yokoi, T., Tani, S., Saiki, Y., Kato, A. (1980) Studies on constituents of Angelicae dahuricae radix. I. On a new furocoumarin derivative. Yakugaku Zasshi, 100, 1258-126 1.
7. Lu, LU., Cai, Y.C. (1982) Thin-layer chromatographic separation and UV spectrophotometric determination of imperatorin and isoimperatorin in Baizhi preparations. Chinese Journal of Pharmaceutical Analysis, 2,
348-350.
8. Zhu, Z.Y. (1982) Quality survey of the branched Bai-zhi (Angelica dahuricaformosana). Chinese Journal of Pharmaceutical Analysis, 2, 221-224.
9. Ding, Y.M., Zhang, H.Q. (1981) Detrmination of coumarins inAngelica dahurica var.formosana by thin-layer chromatography and UV spectrophotometry. Chinese Pharmaceutical Bulletin, 16, 16-17.
10. Kim, S.H., Kang, S.S., Kin, C.M. (1992) Coumarin glycosides from the roots of Angelica dahurica. Archives of Pharmacal Research, 15, 73-77.
11. Baba, K., Matsuyama, Y., Fukumoto, M., Kozawa. M. (1985) 2-Hydroxy-3,4-dimethyl-2-buten-4-olide as a flavoring component of Japanese Bai Zhi. Planta Medico, 51, 64-66.
12. Tani, S., Fujiwara, H., Kato, A. (1984) Studies on constituents of Angelica dahurica. II. Identification of ~nonalactone and y.decalactone by GC and GCIMS as a part of the odor components. Journal of Natural Products, 47, 734.
13. Kimura, Y., Okuda, H.. Baba, K. (1997) Histamine-release effectors from Angelica dahurica var. dahurica root. Journal of Natural Products, 60, 249-25 I.
14. Kimura, Y., Obminami, H., Arichi, H., Okuda, H., Baba, K., Kozawa, M., et al. (1982) Effects of various coumarins from roots of Angelica dahurica on actions of adrenaline, ACTH and insulin in fat cells. Plan to Medica, 45, 183-187.
15. Parrish, J.A., Fitzpatrick, T.B., Tanenbaum, L. (1974) Photochemotherapy of psoriasis with oral methoxsalen and long wave ultraviolet light. New England Journal of Medicine, 291, 1207-1211.
16. Wolff, K., Honigsmann, H. (1981) Clinical aspects of photochemotherapy. Pharmacology and Therapeutics, 12, 381-418.
17. Gia, 0., Palu, G., Palumbo, M.. Antonello, C., Magno, S.M. (1987) Photoreaction of psoralen derivatives with structurally organized DNA. Photochemistry and Photobiology, 45, 87-92.
18. Guiotto, A., Rodighiero, P., Manzini, P., Pastorini, 6., Bordin, F., Baccichetti, F., et al. (1984) 6-Methylangelicins: a new series of potential photochemotherapeutic agents for the treatment of psoriasis. Journal of Medicinal Chemistry, 27, 95 9-966.
19. Nielsen, PE., Bohr, V. (1983) Phototoxic effects of four psoralens on L1210 cells: The correlation with DNA interstrand crosslinking. Photochemistry and Photohiology, 38, 653-657.
20. Shin, K.H., Chung, MS.. Cho, T.S. (1994) Effects of furanocoumarins from Angelica daharica on aldose reductase and galactosemic cataract formation in rats. Archives of Pharmacal Research, 17, 331-336.
21. Babudri, N., Pani, B., Venturini, S., Monti-Bragadin, C. (1986) Mutagenic activity of four furocoumarins:
angelicin, 4,5~-dimethylangelicin, psoralen and 8-methyipsoralen on V-79 Chinese hamster cells. Journal of Environmental Pathology and Toxicological Oncology, 7, 123-129.