MINOR CONSTITUENTS OF QING DAI,A TRADITIONAL CHINESE MEDICINE Ⅰ.ISOLATION, STRUCTURAL DETERMINATION AND SYNTHESIS OF TRYPTANTHRIN AND QINGDAINONE

The study of Qing Dai, a traditional Chinese medicine, has resulted in the isolation of eight minor constituents Ⅲ～Ⅹ(3.3×10^-5～,4.2×10^-4%) after removing of the two major constituents Ⅰ (indigotin) and Ⅱ (indirubin). Constituent Ⅲ (C₁₅H₈ N₂O₂) was found to be identical to the known compound indolo -2,1b-quinazoline6,12-dione (tryptanthrin). Constituent Ⅳ (C₂₃H₁₃N₃O₂) was assigned on the basis of spectrometric data to have structure Ⅳ and confirmed by condensation of Ⅲ with diacetylindoxyl. It was first found from plant origin and designated qingdainone. Ⅲ and Ⅳ were synthesized and found to be both active in test on melanoma B₁₆ and Ⅳ also showed inhibitory action against Lewis lung carcinoma in mice.Structure determination of constituents Ⅴ～Ⅹ is in progress.