BackgroundPhytoecdysteroids are secondary metabolites produced by many plants. Ecdysteroid containing plants have widely been used in medicine and show pharmacological effects such as: anabolic, adaptogenic, genoprotection, hepatoprotection, antiradiation, anti-inflammatory, antidiabetic and anticancerous.GoalThe aim of this study was to determination, isolation and purification of phytoecdysteroids in the Mongolian flora.Materials and МetodsPlants collected during flowering in western and central regions of Mongolia in 2006-2008 and its flowering stage. Plants speciesclassification was identified by Professor D. Oyunchimeg (Department of botany, Hovd university, Mongolia), Professor A. I Pyak and A. L. Ebeli (Department of botany, Tomsk State University, Russia). The main ecdysteroid components were identified in Silene repens by HPLC using the UV spectrometry. The absorption maximum is due to the presence of a conjugated ketone and occurs near 240-250 nm.Results The ecdysteroid containing plants of Mongolian flora has been studied for the first time. Total 297 species from 171 genera in 50 families for ecdysteroid were screened. Most of them represent a random sampling of plants growing in the selected regions. The highest concentration of ecdysteroids was detected in the family of Caryophyllaceae (genera Silene, Elisanthe, Melandrium), Chenopodiaceae (genera Chenopodium and Axyris) and Asteraceae (genera Rhaponticum and Serratula). Ecdysteroids were investigated in 16 from 297 species of the families Сaryophyllaсеае, Asteraceae and Chenopodiaceae of Mongolian flora, but in 6 of them: Silene ichebogdo, Silene mongolica, Elisanthe aprica, Serratula marginata, Chenopodium frutescens, Axyris prostrate at the first time. Ecdysteroid profile has isolated from aerial parts of Silene repens 5 phytoecdysteroids such as: 2-deoxyecdysone, 2-deoxy-20-hydroxyecdysone, polypodine B, 20-hydroxyecdysone, integristerone A and identified by column chromatography and HPLC methods.ConclusionEcdysteroid profile of 297 plant species was investigated. Five ecdysteroids were isolated, their structure were analyzed by HPLC analysis and UV spectrometry in Silene repens. The basic esdysteroids concentrations in plants of Silene jenissensis, Silene repens, Serratula marginata, Stemmacantha uniflorum and Axyris prostrate L. comprise 2.2%, 1.1%, 1.0%, 1.3% and 0.9% dry weight, respectively. Regarding those three species, there appeared a good source for bioactive substance and a new class of pharmaceutical preparation from its aboveground parts is being developed.