✵The article records the herb Rehmannia Root, including its English name, Latin name, Pinyin name, properties and flavors, and its botanical sources—two plant species: (1) Rehmannia glutinosa Libosch., and (2) Rehmannia glutinosa Libosch. f. hueichingensis Hsiao. It provides a detailed introduction to the botanical features, growth characteristics, and ecological environments of these two plant species; the characteristics of the herb Rehmannia Root; its pharmacological actions, medicinal efficacy, and administration guidelines.
Radix Rehmanniae (Rehmannia Root)
Pinyin Name: Dì Huáng, Xiān Dì Huáng
English Name: Rehmannia Root
Latin Name:Radix Rehmanniae Properties and Flavor: Cold, sweet, bitter
Brief Introduction:Radix Rehmanniae is the fresh or dried tuberous root of Rehmannia glutinosa Libosch. It is used to clear heat, cool the blood, nourish yin, and promote fluid production, primarily for treating febrile diseases at the nutrient and blood stages, bleeding due to blood-heat, and thirst in diabetes mellitus. The herb is commonly known as Radix Rehmanniae, Rehmannia Root, or Dì Huáng.
Botanical Source: Radix Rehmanniae (Rehmannia Root) is the fresh or dried tuberous root of (1) Rehmannia glutinosa Libosch. or (2) Rehmannia glutinosa Libosch. f. hueichingensis Hsiao.—both belonging to the genus Rehmannia, family Scrophulariaceae (figwort family), order Lamiales (formerly Tubiflorae). These two commonly used species are described below:
The Rehmannia genus belongs to the Scrophulariaceae family and comprises 6–8 species, distributed in eastern Asia. Six species occur in China, growing in the northwest, southwest, and central to northern regions; some are cultivated for ornamental purposes. These are perennial herbs with rhizomes. They bear globose, multicellular, glandular hairs. Leaves are alternate, obovate to oblong, and coarsely serrated. Flowers are large and short-peduncled, grow singly in leaf axils or arranged in terminal racemes. Calyx is campanulate, apically 5-lobed; lobes are unequal in length—typically the posterior lobe is longest—and entire or secondarily cleft. Corolla is bilabiate, slightly curved, with a swollen tube and deflexed lobes. 4 stamens (rarely five, with the fifth being reduced and included). The ovary is superior, with a ring-like or shallowly cyathiform (cup-shaped) nectary disk at its base; it is bilocular in young fruits and becomes unilocular upon maturity; the style apex is bilobed. Ovules are numerous. The fruit is a capsule, loculicidally dehiscent, with multiple locules. Seeds are small and reticulate.
(1).Rehmannia glutinosa Libosch.
Botanical Description: Rehmannia glutinosa Libosch. is a perennial herb of the family Scrophulariaceae (figwort family) and genus Rehmannia. It is also known as Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. et Mey., or Digitalis glutinosa Gaertn. Common names include Rehmannia glutinosa, Dì Huáng, and Dì Suǐ. The plant grows 10–40 cm tall. The entire plant is densely covered with ash-gray (grayish-white) pilose and glandular hairs. The root is hypertrophic, succulent, tuberous, cylindrical or fusiform (spindle-shaped). The stem is erect, with single or several branches arising from the base. Basal leaves form a rosette; leaf blades are obovate-lanceolate, 3–10 cm long and 1.5–4 cm wide; apex is obtuse; base gradually narrowing and decurrent into a long petiole; leaf surface is often wrinkled; margin is irregularly serrated. Cauline leaves are smaller.
Scapes (flower stalks) are erect and pilose; the upper part of the stem bears a raceme. Floral bracts are foliaceous (leaf-like), either well-developed or reduced. The calyx is campanulate (bell-shaped), apically 5-lobed; lobes triangular, covered with multicellular long pilose and white pilose hairs, with 10 prominent veins. The corolla is broadly tubular (fistuliform), slightly curved, 3–4 cm long; out surface is dark purple; inner surface is yellowish with conspicuous purple striae; apex is 5-lobed and slightly bilabiate. There are four stamens, didynamous; anther bases divaricate. The ovary is superior, ovoid (egg-shaped), bilocular, becoming unilocular after flowering; style is single, stigma is enlarged.
The fruit is a capsule, ovoid or ovate-oblong, apically pointed, with a persistent style; the outer surface is enveloped by the persistent calyx. Seeds are numerous. Flowering occurs from April to May; fruiting from May to June.
Ecological Environment: Rehmannia glutinosa Libosch. is mainly cultivated but also grows wild on hillsides, roadsides, and wastelands at elevations of 50–1,000 meters above sea level.
Growth Characteristics: Rehmannia glutinosa prefers a warm climate and exhibits moderate cold tolerance. Cultivation is best carried out in fields with ample sunlight, deep soil layers, and loose, fertile, neutral or slightly alkaline sandy loam. It can also be grown in mixed soils or fertile clay. Continuous cropping should be avoided. Gramineous crops are recommended as preceding crops; land previously planted with cotton, sesame, legumes, or cucurbits should be avoided, as such rotations increase disease incidence.
Characteristics of the Herb: Roots are fusiform (spindle-shaped) or strip-shaped, 9–15 cm long and 1–6 cm in diameter. The cortex is thin; surface is light reddish-yellow, bearing longitudinal straight or curved wrinkles, bud scars, transverse elongated lenticels, and irregular scars. The herb is succulent and easily fractured; the fracture surface shows a yellowish-white cortex with visible orange oil spots, a yellowish-white xylem (wood portion), and radially arranged tracheae. Odor is slight; taste slightly sweet and slightly bitter.
Dried Rehmannia Root (Gān Dì Huánɡ): Roots are irregularly clumped or oblong, enlarged in the middle and slightly tapered at both ends, 6–12 cm long and 3–6 cm in diameter; some are slender, elongated, slightly flattened, and twisted. The surface is grayish-black or brownish-gray, extremely shriveled, with irregular transversely curved lines. The herb is heavy; its texture is soft yet tough; the fracture surface is grayish-black, brownish-black, or jet-black (corvina), slightly glossy and sticky. It is odorless and tastes slightly sweet.
Pharmacological Actions: (1) Counteracts the decrease in plasma corticosterone concentration induced by continuous dexamethasone administration; (2) Antihypertensive effect; (3) Hypoglycemic effect; (4) Anti-inflammatory activity; (5) Diuretic effect; etc.
Medicinal Efficacy: Clears heat and cools the blood; promotes secretion of saliva and body fluids to moisten dryness. Indicated for acute febrile diseases, fluid depletion with polydipsia, high fever with syncope, dizziness due to excessive heat, hematemesis and epistaxis (bleeding from five aperture or subcutaneous tissue) caused by blood-heat, hematochezia, oral and lingual ulcers, sore throat, consumptive fever with cough, macular eruptions, traumatic injuries, and carbuncles.
Administration of Radix Rehmanniae (Dì Huánɡ):
Reference:
Administration Guide of Radix Rehmanniae (Dì Huánɡ)
TCM Books:
(1) Internally: Fresh Rehmannia root, 12–30 grams; dried Rehmannia root, 9–15 grams; (2) Internally: Water decoction, 0.4–1 liang (≈12–30 grams); juice extraction or paste preparation. External use: Crushed fresh herb applied topically. (3) Internally: Water decoction, 10–30 grams; juice extraction or paste preparation. External use: Apply an appropriate amount—crushed herb topically or juice smeared on affected area.
(2) Rehmannia glutinosa Libosch. f. hueichingensis Hsiao
Botanical Description: Rehmannia glutinosa Libosch. f. hueichingensis Hsiao is a perennial herb of the family Scrophulariaceae (figwort family) and genus Rehmannia. It is also known as Rehmannia glutinosa Libosch f. huechingensis (Chao et Schih) Hsiao, and commonly called Huái Dì Huáng. Its growth habit is similar to that of Rehmannia glutinosa Libosch. It is a forma of R. glutinosa Libosch., growing 25–40 cm tall. The whole plant is densely covered with grayish villous hairs and glandular hairs. The rootstock is hypertrophic, clumped, cylindrical or fusiform (spindle-shaped), 2.5–5 cm in diameter. The stem is solitary and erect, or a few branches arise from the base. Basal leaves are clustered; leaf blades are obovate or oblong; apex is obtuse; base attenuate and decurrent into the petiole; margin with irregularly blunt teeth; surface is often wrinkled; the lower surface of some leaves is purplish. Cauline leaves are rare.
Inflorescences are sparsely racemose; the terminal corolla is broadly tubular and slightly curved, ~4 cm long, purple-red or light purple, sometimes 5-lobed with pale yellow lobes bearing distinct purple lines, bilabiate (2-lipped); There are four stamens, didynamous, inserted near the base of the corolla tube; one pistil with a superior ovary. The fruit is an ovate or ovoid capsule, enclosed by a persistent calyx, containing numerous seeds. Flowering occurs from May to June.
✵The article records the herb Rehmannia Root, including its English name, Latin name, Pinyin name, properties and flavors, and its botanical sources—two plant species: (1) Rehmannia glutinosa Libosch., and (2) Rehmannia glutinosa Libosch. f. hueichingensis Hsiao. It provides a detailed introduction to the botanical features, growth characteristics, and ecological environments of these two plant species; the characteristics of the herb Rehmannia Root; its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Dì Huáng, Xiān Dì Huáng
The Rehmannia genus belongs to the Scrophulariaceae family and comprises 6–8 species, distributed in eastern Asia. Six species occur in China, growing in the northwest, southwest, and central to northern regions; some are cultivated for ornamental purposes. These are perennial herbs with rhizomes. They bear globose, multicellular, glandular hairs. Leaves are alternate, obovate to oblong, and coarsely serrated. Flowers are large and short-peduncled, grow singly in leaf axils or arranged in terminal racemes. Calyx is campanulate, apically 5-lobed; lobes are unequal in length—typically the posterior lobe is longest—and entire or secondarily cleft. Corolla is bilabiate, slightly curved, with a swollen tube and deflexed lobes. 4 stamens (rarely five, with the fifth being reduced and included). The ovary is superior, with a ring-like or shallowly cyathiform (cup-shaped) nectary disk at its base; it is bilocular in young fruits and becomes unilocular upon maturity; the style apex is bilobed. Ovules are numerous. The fruit is a capsule, loculicidally dehiscent, with multiple locules. Seeds are small and reticulate.
Botanical Description: Rehmannia glutinosa Libosch. is a perennial herb of the family Scrophulariaceae (figwort family) and genus Rehmannia. It is also known as Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. et Mey., or Digitalis glutinosa Gaertn. Common names include Rehmannia glutinosa, Dì Huáng, and Dì Suǐ. The plant grows 10–40 cm tall. The entire plant is densely covered with ash-gray (grayish-white) pilose and glandular hairs. The root is hypertrophic, succulent, tuberous, cylindrical or fusiform (spindle-shaped). The stem is erect, with single or several branches arising from the base. Basal leaves form a rosette; leaf blades are obovate-lanceolate, 3–10 cm long and 1.5–4 cm wide; apex is obtuse; base gradually narrowing and decurrent into a long petiole; leaf surface is often wrinkled; margin is irregularly serrated. Cauline leaves are smaller.
Ecological Environment: Rehmannia glutinosa Libosch. is mainly cultivated but also grows wild on hillsides, roadsides, and wastelands at elevations of 50–1,000 meters above sea level.
Characteristics of the Herb: Roots are fusiform (spindle-shaped) or strip-shaped, 9–15 cm long and 1–6 cm in diameter. The cortex is thin; surface is light reddish-yellow, bearing longitudinal straight or curved wrinkles, bud scars, transverse elongated lenticels, and irregular scars. The herb is succulent and easily fractured; the fracture surface shows a yellowish-white cortex with visible orange oil spots, a yellowish-white xylem (wood portion), and radially arranged tracheae. Odor is slight; taste slightly sweet and slightly bitter.
Dried Rehmannia Root (Gān Dì Huánɡ): Roots are irregularly clumped or oblong, enlarged in the middle and slightly tapered at both ends, 6–12 cm long and 3–6 cm in diameter; some are slender, elongated, slightly flattened, and twisted. The surface is grayish-black or brownish-gray, extremely shriveled, with irregular transversely curved lines. The herb is heavy; its texture is soft yet tough; the fracture surface is grayish-black, brownish-black, or jet-black (corvina), slightly glossy and sticky. It is odorless and tastes slightly sweet.
Botanical Description: Rehmannia glutinosa Libosch. f. hueichingensis Hsiao is a perennial herb of the family Scrophulariaceae (figwort family) and genus Rehmannia. It is also known as Rehmannia glutinosa Libosch f. huechingensis (Chao et Schih) Hsiao, and commonly called Huái Dì Huáng. Its growth habit is similar to that of Rehmannia glutinosa Libosch. It is a forma of R. glutinosa Libosch., growing 25–40 cm tall. The whole plant is densely covered with grayish villous hairs and glandular hairs. The rootstock is hypertrophic, clumped, cylindrical or fusiform (spindle-shaped), 2.5–5 cm in diameter. The stem is solitary and erect, or a few branches arise from the base. Basal leaves are clustered; leaf blades are obovate or oblong; apex is obtuse; base attenuate and decurrent into the petiole; margin with irregularly blunt teeth; surface is often wrinkled; the lower surface of some leaves is purplish. Cauline leaves are rare.
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