dictamnus root bark

Dictamnus root bark, also known as Cortex Dictamni or Bai Xian Pi, is the dried root bark of Dictamnus dasycarpus Turcz. or Dictamnus albus L. (family Rutaceae). It is a cornerstone of Traditional Chinese Medicine (TCM) widely utilized for its heat-clearing, dampness-drying, wind-dispelling, and antipruritic properties. The herb is primarily indicated for inflammatory and allergic skin conditions, including atopic dermatitis (eczema), psoriasis, urticaria, seborrheic dermatitis, and generalized pruritus, as well as damp-heat jaundice and rheumatoid arthritis. Phytochemical studies have identified furoquinoline alkaloids (such as dictamnine, skimmianine, and γ-fagarine) and limonoids (such as obacunone, limonin, and fraxinellone) as its primary bioactive constituents. These compounds exert anti-inflammatory, anti-allergic, and antimicrobial effects by modulating key molecular targets, including MRGPRX2, NR1D1, c-Met, NRF2, MIF, MAPK1, and PINK1. Dictamnus root bark is typically administered orally as a decoction or concentrated granules, or applied topically in creams and washes.