Herbal Research

Long Dan

RADIX GENTIANAE (GENTIAN ROOT)

Long Dan consists of the dried root and rhizome of Gentiana manshurica Kitag., Gentiana scabra Bge., Gentiana triflora Pall, or Gentiana rigescens Franch. (Gentianaceae). The herb prepared from G. manshurica, G. scabra and G. triflora is mainly produced in the northeastern provinces of Heilongjiang, Jilin and Liaoning, and that from G. rigescens is produced in the provinces of Yunnan, Sichuan, Guizhou, Hunan and Guangxi. The herb is collected in the spring and autumn, washed clean and then dried.

CHEMISTRY

Gentiana plants usually contain bitter principles, mainly secoiridoid compounds. The major bitter principle of the all four Gentiana species is gentiopicroside (gentiopicrin), first isolated from Gentiana lutea, accounting for 3.66-6.34% of dry weight of the herb1'2. In addition to gentiopicroside, sweroside, swertiamarin, amarogentin and amaroswerin were also isolated and identified2-4. Furthermore, another two secoiridoid glycosides named trifloroside and scabraside were identified in the root of G. triflora var. japonica and G. scabra var. buergeri5,6.
The content of gentiopicroside in the root of G. scabra was dependent on the age of the plant and the season of collection. It was highest (7.8%) in the autumn during the third year of cultivation7.

PHARMACOLOGY

Stomachic Effect

The herb, on account of its bitter principles, displays a stomachic effect. Gentiopicroside increased the secretion of gastric juice as well as of free hydrochloric acid in dogs when it was administered through gastric catheter but not when it was given sublingually or intravenously. However, no increases in food consumption and body weight was observed in rats despite the increase in gastric juice and acid secretion8.

Hepatoprotective and Choleretic Effects

Hepatic necrosis and cellular degeneration caused by carbon tetrachionde in mice was decreased after intraperitoneal administration of 30 g/kg of the injection solution of the herb once daily for 5 days. The liver glycogen level was increased. Intraduodenal administration of 50 g/kg of the injection significantly increased bile flow in both healthy and hepatic injury rats. The bile flow was also increased in dogs after receiving intravenous dose of 4.5 g/kg of the injection solution8.

Hypotensive and Diuretic Effects

The blood pressure of rabbits was decreased from 70 mmHg to 40 mmHg after given 8-10 ml/kg of the 20% tincture of the herb intravenously; the effect lasted for approximately 15 mins. Perfusion of the 20% aqueous extract or tincture of the herb into the isolated toad heart slowed down the heart rate and reduced the amplitude of cardiac contraction. Administration of 10 g/kg of the injection solution through the ear vein of rabbits increased urine excretion from 0.76 ml per half hour to 2.64 ml on average8.

Antibacterial and Antiinflammatory Effects

The decoction of the herb inhibited in vitro the growth of Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhi, Staphylococcus aureus, Trichophyton cypsum and Nocardia asteroides8. Gentiopicroside showed antiinflammatory activity in carrageenininduced paw edema in rats9.

FUNCTIONS AND APPLICATIONS

Traditional Description

Long Dan has a bitter taste and a cold property, acting on the liver and gallbladder channels. It has the functions of:

(i) eliminating damp-heat, used in jaundice due to damp-heat, swelling and itching of the vulva with excessive leukorrhea and eczema accompanied by itching; and
(ii) quenching fire of the liver and gallbladder, used in blood-shoot eyes, impairment of hearing, pain in the costal regions and bitter taste in the mouth, and convulsion.

Applications
Appetizer

The herb has been used as an appetizer in the form of tincture.

Encephalitis B

In mild cases, a 20% syrup of the herb was given at 10-15 ml trice daily by mouth. In cases with coma or vomiting, 2-4 ml of the 2:1 injection solution was given intramuscularly 3-4 times daily up to 3 days after the subsidence of fever. Routine treatment with Western medicines was necessary in moderate and serious cases. In 23 cases (11 serious, 6 moderate and 6 mild) so treated, 18 had normal temperature in 3 days, convulsive symptoms were controlled within 24 h in 11/15 cases (4 others were controlled in 2 days). Only one serious developed sequelae of the disease.

Hepatitis and other damp-heat syndromes of the liver and gallbladder

A well-known prescription "Longdan Xiegan Tang" containing the herb as the principal ingredient can be used in hepatitis and other syndromes due to damp-heat in the liver and gallbladder, including cholecystitis, conjunctivitis, keratitis, corneal ulcer, otitis media, acute pyelonephritis, cystitis, urethritis, acute pelvic infection, eczema and drug rash.

DOSAGE

3-9g.

SIDE EFFECTS AND TOXICITY

The herb may cause impairment of the digestive function and occasionally headache, flushing of the face and vertigo when it is taken after meal or in overdose8.

REFERENCES

1. lnouye. H., Yoshida, T., Nakamura, Y., Tohita, 5. (1968) Die Stereochemie einiger Secoiridoidgiucoside und die Revision der Struktur des Gentiopicrosids. Tetrahedron Letters. 4429-4432.
2. Zhou, RH. (1993) Resource Science of Chinese Medicinal Materials, pp. 411--4 17. Beijing: China Medical & Pharmaceutical Sciences Press.
3. Luo, J.P., Lou, Z.C. (1986) Separation and identification of gentiopicroside, swertiamarin and sweroside in the traditional drug longdan, Radix Gentianae. Chinese Traditional and Herbal Drugs, 17, 145-149.
4. Luo, J.P., Lou, Z.C. (1985) Silica gel thin layer and polyamide sheet chromatographic identification of the secoiridoid glucosides in cartain Gentiana species used in Chinese traditional medicine Long Dan. Chinese Journal of Pharmaceutical Analysis, 5, 7-10.
5. lnouye, H., Ueda, S., Nakamura, Y., lnoue, K., Hayano, T., Matsumura, H. (1974) Uber die Monoterpenglycoside und verwandte Naturstoffe XXIV. Triflorosid, em neues Secoiridoidglucosid aus Gentiana triflora var. japonica. Tetrahedron, 30, 571-577.
6. Ikeshiro, Y., Tomita, Y. (1983) A new bitter secoiridoid glucoside from Gentiana scabra var. buergeri. P/onto Medico, 48, 169-173.
7. Lu, Y.R., Yang, X.H., Shao, A.X. (1986) Comparison of gentiopicroside contents in the root and its preparation of Gentiana scabra
collected in different seasons at different years of cultivation. Bulletin of Chinese Materia Medico, 11, 298-300.
8. Wang, Y.S. (1983) Pharmacology and Applications of Chinese Materia Medica, pp. 295-299. Beijing: People's Health Publisher.
9. Hayasbi, T., Kubo, M. (1979) Antiinflammatory secoidoids. Nippon Kokai Tokkyo Koho 79, 26, 323 (CA l979;9l:9485y).