Abstract: Nine components of the essential oil of Rqbdosia rubescens were isolated by distillation and alumina column chromatography and identified by TLC, GLC, determination of physical constants and IR spectrum: a-pinene(1%), β-pinene (0. 16 % ), limonene (0.16%), 1, 8-cineole (0.33 %), P-cymene (0.16%), nonaldehyde (1.33%), decanal (1%), 0-elemene (20.3%) and palmitic acid (6.6%). Eight compounds (I-VIII)were isolated from the ether extract of the leaves by alumina or silica gel column chromatpgraphy.By means of UV, IR, MS, and NMR spectroscopy, preparation of derivatives and determination of physico-chemical constants, three of them, namely (I), (II)and(VI), were identified as oridonin, ponieidiri and a-amyrin respectively. According to the pharmacological and primary clinical findings, oridonin and ponicidin are two of the anti-neoplastic principles of this plaht.

Key words: chemical, constituents, antitumor, plant