Study of the sucrose effects on tropane alkaloid contents of Datura under in vitro culture condition Parisa FathiRezaei Department of Biology, University of Maragheh, Maragheh, Iran Introduction Medicinal plants are the most important source of emergency drugs for the majority of the world’s population. Biotechnological methods have become an important tool in pharmaceutical drug research and development. In vitro regeneration has huge potential for the production of high-quality plant-derived medicine. Alkaloids represent a highly diverse group of compounds are purported to play a defensive role against herbivores and pathogens. Many of them have been exploited as pharmaceuticals, stimulants, narcotics, and poisons. The scopolamine and its precursor hyoscyamine which are found mainly in Solanaceae family are used as parasympatholytics that competitively antagonize acetylcholine. Datura stramonium known as a medicinal plant is a rich source of tropane alkaloids such as atropine, hyoscyamine and scopolamine. In this investigation effects of sucrose as a carbon source were evaluated on scopolamine and hyoscyamine levels of Datura seedlings under in vitro culture condition. Methods Datura seeds were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of sucrose (0, 30 and 45 g/L). After two month seedlings were gathered and their tropane alkaloids extracted according to the Kamada and et al protocol. The extracts were analyzed by High pressure liquid chromatography (HPLC) for the determination of hyoscyamine and scopolamine contents. The mobile phase was water: acetonitrile (75:25), flow rate was 1 ml/min and peaks were detected 215 nm. The hyoscyamine sulphate and Scopolamine hydrobromide were used as standards. Results According to the HPLC chromatograms, scopolamine content of roots of sucrose-treated seedlings was increased by increasing the sucrose concentration, but in shoots the amount was more or less similar to untreated seed