Root of Isatis tinctoria L., family Cruciferae, or Baphicacanthus cusia
(Nees) Brem, family Acanthaceae.
tinctoria: Root slender-linear; 10-20 cm long and 0.5-1.0 cm in diameter;
root stock marked by petiole basal traces and dense tuberdes; epidermis
grey-yellow, with transversely long lenticels. B. cusia: Root irregularly
branching, unequal in length, 0.5-1.0 cm in diameter, with grey-blue and
lustrous surface. Bitter in taste, cold in nature, and attributive t9
heart and lung channels.
Similar to Folium Isatidis, but lesser bitter in flavour and cold in nature,
used for seasonal febrile diseases, pestilence, mumps, eruptive diseases,
inflammatory diseases with redness of skin, sorethroat, etc.
I. Clinically effective on influenza and experimentally virustatic on
influenza virus PR8.
2. Its component, indican, is bacteriostatic.