Defi nition
Radix Gentianae Scabrae consists of the dried roots and rhizomes of Gen-
tiana scabra Bunge (Gentianaceae) (1–4).
Synonyms
Gentiana buergeri Miq., G. fortunei Hook. (5).
Selected vernacular names
Chinese gentian, dancao, Japanese gentian, kudancao, longdan, longdan- cao, tourindou (1, 2, 4, 6, 7).
Geographical distribution
Indigenous to the Korean peninsula and to China and Japan (8, 9).
Description
A perennial herb. Roots white, 10–15 cm long, with numerous short branches. Rhizomes rather short. Stems 20–100 cm long, with 10–20 pairs of leaves. Leaves lanceolate to narrowly deltoid-ovate, 4–8 cm long, 1–3 cm wide, grad- ually acuminate, three-nerved, green above, paler beneath, usually sessile, mar- gin of upper leaves papillose. Flowers few to rather numerous, sessile, 4.5–6 cm long, purplish-blue; calyx tube 12–18 mm long, the lobes rather unequal, linear-lanceolate; corolla plaits deltoid, often toothed. Capsules stipitate, not exerted; seeds broadly lanceolate, short-caudate at both ends (10, 11).
Plant material of interest: dried roots and rhizomes
General appearance
Irregular, cylindrical, short yellowish-brown to greyish-brown rhizome with numerous slender roots. Roots 10–15 cm long, about 0.3 cm in diameter, with longitudinal, coarse wrinkles on the outer surface; fl exible, fractured surface, smooth, yellow-brown. Rhizome about 2 cm long, 0.7 cm in diameter, with buds or short remains of stems at the top (2).
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Organoleptic properties
Odour: characteristic; taste: bitter (1–4).
Microscopic characteristics
Root section shows epidermis, endodermis and a few layers of primary cortex; usually the outermost layers of the endodermis consisting of char- acteristic cells divided into a few daughter cells, often with collenchyma of one to two layers in contact with the inner side; secondary cortex hav- ing rents here and there, and irregularly scattered sieve tubes; vessels rang- ing rather radially in the xylem, and sieve tubes existing in the phloem. Root and rhizomes have distinct pith, rarely with sieve tubes, and paren- chymatous cells containing needle, plate or rhombic crystals of calcium oxalate, and oil droplets. Starch grains mostly absent (1, 2, 4).
Powdered plant material
Fragments of parenchymatous cells containing oil droplets and minute needle crystals of calcium oxalate. Cells of exodermis spindle-shaped in surface view, each cell divided by transverse walls into several small rect- angular cells. Cells of endodermis subrectangular in surface view, fairly large, periclinal walls showing minute transverse striations, each cell di- vided by longitudinal septa walls into several small palisade-like cells, longitudinal septa mostly beaded. Vessels mainly reticulate and scalari- form, 20–30 μm but can be up to 45 μm in diameter (2, 4).
General identity tests
Macroscopic and microscopic examinations (1–4), microchemical tests (1,
3) and thin-layer chromatography (2, 4).
Purity tests
Microbiological
Tests for specifi c microorganisms and microbial contamination limits are as described in the WHO guidelines on quality control methods for me- dicinal plants (12).
Total ash
Not more than 7% (1–4).
Acid-insoluble ash
Not more than 3% (1–3).
Alcohol-soluble extractive
Not less than 30% (3).
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Loss on drying
Not more than 8% (3).
Pesticide residues
The recommended maximum limit of aldrin and dieldrin is not more than 0.05 mg/kg (13). For other pesticides, see the European pharmacopoeia (13), and the WHO guidelines on quality control methods for medicinal plants (12) and pesticide residues (14).
Heavy metals
For maximum limits and analysis of heavy metals, consult the WHO guidelines on quality control methods for medicinal plants (12).
Radioactive residues
Where applicable, consult the WHO guidelines on quality control meth- ods for medicinal plants (12) for the analysis of radioactive isotopes.
Other purity tests
Chemical, foreign organic matter and water-soluble extractive tests to be established in accordance with national requirements.
Chemical assays
Contains not less than 1.0% gentiopicroside determined by high- performance liquid chromatography (4).
Major chemical constituents
The major constituents are bitter secoiridoid monoterpenes including gentiopicroside (gentiopicrin; 0.5–10%), swertiamarin and sweroside. Xanthones, the alkaloid gentianine (0.05%) and gentianadine are other signifi cant constituents. The bitter principle amarogentin found in Gen-
tiana lutea is absent (5, 7, 15–17). Representative structures of the secoiri-
doid monoterpenes are presented below.
WHO monographs on selected medicinal plants
gentiopicroside sweroside amarogentin O O O H O H H2C O OH HO HO H O OH OH HO O O O O H O H H2C O OH HO HO OH O O O H O H H2C O OH HO HO OH H SMPvol3 layout.indd 162 SMPvol3 layout.indd 162 10.8.2007 12:10:1910.8.2007 12:10:19
163
Medicinal uses
Uses supported by clinical data
None.
Uses described in pharmacopoeias and well established documents
Symptomatic treatment of liver disorders, cholecystitis and lack of appe- tite (3, 6).
Uses described in traditional medicine
Treatment of convulsions, eczema, fungal infections, hearing impairment, infl ammation, leukorrhoea, otitis media, urinary tract infections, herpes zoster and pruritus vulvae (3, 6, 7).
Pharmacology
Experimental pharmacology
Antimicrobial activity
A 90% ethanol extract of the roots did not inhibit the growth of Bacillus
subtilis, Candida albicans, Escherichia coli, Staphylococcus aureus or Streptococcus faecalis in vitro (18). An infusion of Radix Gentianae Sca-
brae had no antiviral activity in vitro when tested against herpes simplex virus 1, measles virus or poliovirus 1 (19).
Antihepatotoxic activity
Intraperitoneal administration of 1.0 g/kg body weight (bw) of a dried methanol extract of the roots and rhizomes, dissolved in normal saline, inhibited hepatotoxicity induced by carbon tetrachloride in rats but did not decrease the activity of alkaline phosphatase (20). Intraperitoneal ad- ministration of 1.0 g/kg bw of a dried methanol extract of the roots and rhizomes, dissolved in normal saline, to rats decreased increased gluta- mate-oxaloacetate transaminase activity induced by treatment with α-naphthylisothiocyanate and decreased plasma bilirubin concentrations, but did not decrease the activities of glutamate-pyruvate transaminase or lactate dehydrogenase (20). Intragastric administration of 670.0 mg/kg bw of a 1-butanol, chloroform or methanol extract of the roots and rhi- zomes prevented hepatotoxicity induced by carbon tetrachloride in mice (21, 22). The 1-butanol and chloroform extracts also inhibited the in- creased glutamate-pyruvate transaminase activity induced by carbon tet- rachloride (20). Intraperitoneal administration of an aqueous or dried 50% methanol extract of the roots and rhizomes (dose not specifi ed) pre- vented hepatotoxicity induced by carbon tetrachloride in mice (23). In- traperitoneal administration of 25.0–50.0 mg/kg bw of gentiopicroside
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WHO monographs on selected medicinal plants
inhibited liver injury induced by D-galactosamine/lipopolysaccharide in mice (24). Intraperitoneal pretreatment of mice with 30.0–60.0 mg/kg bw of gentiopicroside per day for 5 days, suppressed the increased concentra- tions of serum hepatic aminotransferases induced by carbon tetra- chloride (25).
Anti-infl ammatory activity
Intraperitoneal administration of 90.0 mg/kg bw of gentianine to rats reduced swelling and infl ammation of the ankle joint of the hind leg induced by formalin or egg white (26, 27).
Antispasmodic activity
A 95% ethanol extract of the roots and rhizomes, 200.0 μg/ml, did not inhibit barium- or histamine-induced smooth muscle contractions in guinea-pig ileum in vitro; however, an aqueous extract, 200.0 μg/ml, inhibited barium-induced contractions (28). The essential oil of Radix Gentianae Scabrae induced relaxation of smooth muscles in guinea-pig trachea and ileum in vitro, with median effective doses of 108.0 mg/l and 76.0 mg/l, respectively (29).
Central nervous system effects
Intraperitoneal administration of 250.0 mg/kg bw of a methanol or 75% methanol extract of the roots and rhizomes per day for 3 days to mice did not enhance the effects of barbiturates or increase hexobarbital-induced sleeping times (30–32). Intragastric administration of 670.0 mg/kg bw of a 1-butanol or chloroform extract of the roots did not potentiate the ef- fects of barbiturates in mice (20). An ethanol extract of the roots and rhi- zomes (concentration not specifi ed) inhibited the reuptake of serotonin in rat brainstem neurons in vitro (33). Intraperitoneal administration of 25.0–100.0 mg/kg bw of gentianine or gentianadine potentiated the anaes- thetic effects of pentobarbital and chloral hydrate in mice (6). Intragastric administration of 200.0–400.0 mg/kg bw of gentianine or 700.0–1000.0 mg/kg bw of gentianidine resulted in sedation and reduced spontaneous activity in mice (6).
Choleretic activity
Intraduodenal administration of 50.0 g/kg bw of an aqueous extract of the roots and rhizomes to healthy rats or rats with hepatic injuries in- creased bile fl ow. A similar effect was observed in healthy dogs after in- travenous administration of 4.5 g/kg bw of the extract (6). Intragastric administration of 1.8 g/kg bw of a dried methanol extract of the roots and rhizomes had choleretic effects in rats (34).
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Toxicology
The oral median lethal doses (LD50) of gentianine and gentianadine in mice were 400.0 mg/kg bw and 1250.0 mg/kg bw, respectively (6, 35). The subcutaneous LD50 of gentianine in mice was > 500.0 mg/kg bw, and the intravenous LD50 was 250.0–300.0 mg/kg bw (6). The intraperitoneal LD50 of a 90% ethanol extract of the roots and rhizomes in mice was 1.0 g/kg bw (18). 2-Hydroxy-3-methoxy benzoic acid glucose ester iso- lated from the roots and rhizomes was found to be a potent antagonist of platelet-activating factor in vitro (36).
Clinical pharmacology