Many types of compounds have been isolated from higher plants till now, that is, alkaloids, terpenes, lignans, steroids and so on. One of them, named as RA series Cyclic hexapeptides isolated from Rubia akane and R. cordijofia also have strong antineoplastic activity against various types of tumors. Till now 10 kinds ofRA series compounds were isolated and named as RA - I, II, III, IV, V, VI, VII, VIII, IX and X. Moreover,monogl-ucoside of RA - V newly Isolated from same plant. Many kinds of derivatives including natural RAcompounds were tested for QSAR, and one of them, RA - VII was screened up as a most suitable substance asan antitumor agent. RA - VII(=RA-700) has strong cytotoxic activity against KB cells, P388 Iymphocyticleukemia and MM2 mammary carcinoma cells. RA - VII has been under investigation for Phase I clinical trials.

In the preliminary antitumor screening tests of Crude Drugs and collected plants, the methanol ic extract of Forsythia Fruits in Korean marcket showed signif icant cytotoxic activity against Chinese hamster V-79 cells, but that in Japanese market did not. The former was identifid as Forsythia viridissima Lindley and latter as F.suspensa Vahl on the basis of the morphological observation. When an aqueous solution of the extract prepared from the fruits of F. viridissima (Oleaceae) was partitioned successively with n-hexane, methylene chloride, n-butanol, the cytoyoxic activitywas concetrated in the methylene chloride extract. Fractionation of the extract was made with the guidance of bioassay against V-79 cells to give cytotoxic lignans, matariresiol (1) and arctigenin (2). Their ICso values of compounds 1 and 2 were respectively 7.8 μg/ml 1 and 1.65 μg/ml. Also, their structures were confirmed by comparison of physical and spectral data in the literature.