The dichloromethane fraction from the ethanol extract of the aerial parts of Taraxacum offi cinale showed a good inhibitory effect on hepatocellular carcinoma cells (HCC). As a result of a series of column chromatographies and usage of nuclear magnetic resonances spectrometric methods and mass spectroscopy 9 known components as taraxasterol (1), taraxasterylacetate (2),pseudotaraxasterol (3), lupeolacetate (4), b-sitosterol (5), b-sitosterylglucopyranose (6), palmitic acid (7), monopalmitin (8) and chrysoerol (9) have been determined. Amongst them palmitic acid, monopalmitin and chrysoeriol have been determined for the fi rst time in the aerial parts of Taraxacum offi cinale. Six compounds as 1, 3, 4, 5, 6 and 7 were tested for their inhibitory activity on HCC and only palmitic acid exhibited more activity against HCC than others, suppressing cell proliferation, migration, adhesion and activated cell apoptosis.Keywords: Triterpenol and sterol derivatives; palmitic acid; hepatocellular carcinoma inhibition activity;IntroductionTaraxacum, commonly called dandelion, is a large genus of fl owering plants in the Asteraceae family. The latin name Taraxacum is from the Greek and means “disease remedy”, while the English name dandelion is originated from the French dent de leon, meaning “lion’s tooth”1. The Mongolian well-recognised name is “baaban beeben”, while in Japan it calls hokouei, respectively. Consequently, Taraxacum is widespread plant throughout the world, in particular, 19 species are found in the Mongolian fl ora2. Generally Taraxacum is considered weedy plant used as a medicinal herb and for food preparation. Traditionally, Taraxacum offi cinale Weber ex Wigg. in Mongolian and Tibetan medicine under the name “khurmong” the root has been used as the composition in a remedy for jaundice and other disorders of the liver and gallbladder, whilethe leaf is used as a diuretic and bitter digestive stimulant. Moreover, fresh dandelion stem latex is used for the warts treatment1,3-6. Taraxacum leaf is included as a medicinal drug in Herbal Pharmacopeia of several European countries. Numerous biological activity tests resulted that Taraxacum possessed an infl ammation modulating activity7-9, diuretic activity comparable to furosemide10, digestive stimulant, appetitive effect and activator for bile fl ow11-12, hypoglycemic activity13 and antitumor activity14. No side effects and carcinogenicity of T. offi cinale extracts and preparations have been noticed. Chemical constituents of T. offi cinale arewell studied. Scientists of different countries reported that whole plant T. offi cinale containedabundance of bitter principles as terpenoids and sterols, bile like terpenes and sterols, various fl avonoids and phenolic acids, large amount of polysaccharides as inulin and fructosans11,15-17.Also, dandelion is a rich in minerals such as iron, potassium and zinc18,19. In this work we are describing activity-guided isolation and the molecular structure elucidation of components from the dichloromethane fraction of the aerial parts of T. offi cinale, from the Mongolian fl ora.