Introduction of Bai Xian Pi: Dittany Root-bark.

 ✵The article records the herb Dittany Root-bark, including its English name, Latin name, Pinyin name, properties and flavor, the botanical source as defined in classical herbal texts—namely, (1) Dictamnus dasycarpus Turcz., (2) Dictamnus angustifolius G. Don ex Sweet., and the botanical source of the herb Burning Bush, (3) Dictamnus albus—and provides a detailed introduction to the botanical features, growth characteristics, and ecological environments of these three plant species, as well as the characteristics of Dittany Root-bark, its pharmacological actions, medicinal efficacy, and administration guidelines.

Cortex Dictamni (Dittany Root-bark)

 Pinyin Name: Bái Xiān Pí
 English Name: Dittany Root-bark
 Latin Name: Cortex Dictamni
 Properties and Flavor: Cold, bitter, salty

 Brief Introduction: Cortex Dictamni is the dried root-bark of Dictamnus dasycarpus Turcz., used internally or externally for skin diseases characterized by excessive secretion and pruritus. It is commonly known as Cortex Dictamni, Dittany Root-bark, or Bái Xiān Pí.

 Botanical Source: Cortex Dictamni (Dittany Root-bark) is the dried root-bark of Dictamnus dasycarpus Turcz., a plant of the genus Dictamnus L., family Rutaceae (rue family), order Sapindales.

 Classical Chinese herbal works define Cortex Dictamni—or Densefruit Dictamnus Root-bark (Bái Xiān Pí)—as the cortex or root bark of Rutaceae plants: (1) Dictamnus dasycarpus Turcz. and (2) Dictamnus angustifolius G. Don ex Sweet. Official herbal texts recognize only (1) Dictamnus dasycarpus Turcz. as the authorized source. Other classical herbal works identify the herb Burning Bush as derived from (3) Dictamnus albus. These three commonly used species are described below:

(1) Dictamnus dasycarpus Turcz.

 Botanical Description: Dictamnus dasycarpus Turcz. is a perennial herb of the Rutaceae family (rue family) and genus Dictamnus L. It is commonly known as Densefruit Dictamnus or Bái Xiān. The base is ligneous (woody), and the plant grows up to 1 meter tall. The whole plant emits a distinctive odor. Roots are succulent, with numerous lateral roots; the bark is yellowish-white to tawny (yellowish-brown). Leaves are imparipinnate and alternate; the rachis bears narrow wings and lacks a petiole; leaflets number 9–13, ovate (egg-shaped) to elliptic, 3.5–9 cm long and 2–4 cm wide; apex is acute, base is cuneate, margin is serrulate; upper surface is dark green and densely covered with glandular dots; lower surface is pale green with sparse glandular dots.

 Inflorescences are terminal racemes, up to 30 cm long; floral axis and pedicels are covered with white pubescence and black glandular hairs; pedicels (flower stalks) measure 1–2.5 cm and bear a single linear bract at the base; 5 sepals, ovate-lanceolate, ~5 mm long and ~2 mm wide, with bases connate; 5 petals, light red with purplish lines, oblanceolate or oblong, ~25 mm long and 5–7 mm wide, gradually narrowing at the base into a petiole-like structure; 10 stamens; ovary is superior, 5-locular.

 Fruit is a capsule, densely covered with glandular hairs, 5-lobed at maturity, each lobe terminating in a needle-like point. Seeds number 2–3 per fruit, subspherical, ~3 mm in diameter, mucronate at the apex, black and glossy. Flowering occurs from April to May; fruiting occurs in June.

 Ecological Environment: Dictamnus dasycarpus Turcz. grows on earthy slopes, shrublands, sandy soils, forest margins, low shrublands on sandy soils, hilly slopes, flatland shrubs or grasslands, sparse forests, and limestone mountains.

 Growth Characteristics: Dictamnus dasycarpus prefers a warm and humid climate; it exhibits strong adaptability, cold tolerance, but is drought-sensitive, waterlogging-intolerant, and shade-preferring (intolerant of intense sunlight).

 Characteristics of the Herb: The root-bark of Dictamnus dasycarpus Turcz. occurs in coiled or block-like pieces, 5–15 cm long, 1–2 cm in diameter, and 2–5 mm thick. The outer surface is ash-gray (grayish-white) or pale gray-yellow, bearing fine longitudinal wrinkles and rootlet scars, often with protruding granular dots; the inner surface is off-white with fine longitudinal striations. The texture is brittle and friable; dust disperses upon breaking; fracture surface is uneven and slightly laminated; when the outer layer is peeled away, minute shiny spots become visible under light. The herb has a mutton-like odor and a slightly bitter taste.

 Pharmacological Actions: (1) In vitro inhibition of various pathogenic fungi; (2) anti-inflammatory effects; (3) antipyretic effects; (4) antineoplastic (anti-cancer) effects; (5) uterine smooth muscle contractile effects.

 Medicinal Efficacy: Clears heat and dries dampness, dispels wind pathogens and alleviates pruritus, and detoxifies. It is indicated for carbuncles and ulcers due to heat-dampness, measles caused by wind-heat combined with damp-toxin, weeping eczema ("yellow water"), eczema, rubella, scabies, sores, rheumatic arthralgia with fever, jaundice, and dark-yellow or reddish urine.

 Administration of Cortex Dictamni (Bái Xiān Pí): 
 

Reference:	Administration Guide of Cortex Dictamni (Bái Xiān Pí)
TCM Books:	(1) Internally: 4.5–9 grams; external use: appropriate amount—apply as a decoction wash or as finely ground herb powder. (2) Internally: water decoction, 2–5 qián (≈6–15 grams); external use: decoction wash. (3) Internally:water decoction, 6–15 grams; also prepared as pills or powders. External use: appropriate amount—decoction wash or finely ground herb powder applied topically.

(2) Dictamnus angustifolius G.Don ex Sweet.

 Botanical Description: Dictamnus angustifolius G. Don ex Sweet is a perennial herb of the Rutaceae family (rue family) and genus Dictamnus L. It is commonly known as Narrow-leaf Dictamnus or Xiǎo Yè Bái Xiān (Xia Ye Bai Xian), Tuó’ěrbùtì (Tuo Er Bu Ti), among others. Plants grow 30–80 cm tall. Stems are erect and mostly branched from the base; densely covered with long pubescence, while the lower portion is glabrous or sparsely pubescent; fragrant. Leaves are imparipinnate and alternate; rachis is pubescent, unwinged at the base; petiolules are very short; leaflets 7–15, oblong or oblong-ovate, 5–10 cm long and 2–3 cm wide; apex is acuminate, base is broadly cuneate or obtuse, margin is serrulate and recurved (curving downward); upper surface is glabrous; lower surface is sparsely hairy along the veins.

 Inflorescences are terminal racemes, densely covered with glandular hairs and brownish (hazel) hairs; bracts are linear-lanceolate, densely covered with dark brown glandular hairs; sepals 5, lanceolate-linear, 7–9 mm long, apex is acute, densely glandular-hairy; corolla lobes are lanceolate or oblong, 2–4.5 cm long, pale pink with purplish-brown (puce) hairs, apex is acute or obtuse, base gradually narrowed into a claw-like structure; stamens 10, free, filaments are pilose; ovary is superior, sparsely white-hairy, style is glabrous.

 Fruit is a capsule, densely covered with glandular hairs and fine hairs, 5-lobed at maturity, each lobe terminating in a needle-like point. Seeds 2–3 per fruit, subspherical, black and glossy. Flowering occurs from May to July; fruiting from August to September.

 Ecological Environment: Dictamnus angustifolius G. Don ex Sweet grows in mountain shrublands and forests, and on sunny mountain slopes.

(3) Dictamnus albus

 Botanical Description: Dictamnus albus, commonly known as Burning Bush, is a perennial herb of the Rutaceae family (rue family) and genus Dictamnus L. Medicinal parts include the dried (and occasionally fresh) leaves, roots, and root bark. Other vernacular names include Fraxinella, Dittany, Gas Plant, and Diptam. Inflorescences are terminal racemes bearing large, irregular, pink flowers with dark longitudinal veins. Each flower has 5 sepals and 5 petals. Two bracteoles are present, slightly zygomorphic. Stamens number 10, threadlike and elongated, curving forward. The ovary consists of 5 carpels fused at the base of a short gynophore. The fruit is a dehiscent capsule that splits into mericarps, ejecting the seeds. Plants reach 0.5–1.5 m in height. Numerous erect, unbranched, glandular-sticky shoots arise from the rootstock. Leaves are alternate, odd-pinnate, with 7–11 leaflets, translucently punctate with oil glands. The plant emits a strong lemon- or cinnamon-like fragrance; its volatile oil is highly flammable.

 Ecological Environment: Dictamnus albus (Burning Bush) grows in mountain shrublands and forest understories, and on sunny slopes.
 

Article Link:

  https://tcmfans.club/herbalism/chdd/cortexdictamni.html
  

 

 URL QR code:
  

 

References:

• 1.Introduction of Bai Xian Pi: Dittany Root-bark

 Edited and last revised: January 5, 2023