1. Betulin : chemical esterification for therapeutical purposes Iulia Pînzaru 1, Cristina Trandafirescu 2, Zoltan Szabadai 3, Marius Mioc 2, Lenuţa-Maria Şuta 4, Cristina Dehelean 5, Codruţa Şoica 2 1 “Victor Babeş” University of Medicine and Pharmacy, Departament of Physical Chemistry, Faculty of Pharmacy, Timişoara, România 2 “Victor Babeş” University of Medicine and Pharmacy, Departament of Pharmaceutical Chemistry, Faculty of Pharmacy, Timişoara, România 3 “Victor Babeş” University of Medicine and Pharmacy, Departament of Drug Analysis, Faculty of Pharmacy, Timişoara, România 4 “Victor Babeş” University of Medicine and Pharmacy, Departament of Pharmaceutical Technology, Faculty of Pharmacy, Timişoara, România 5 “Victor Babeş” University of Medicine and Pharmacy, Departament of Toxicology, Faculty of Pharmacy, Timişoara, România INTRODUCTION The first purpose of this study was the extraction of betulin from white birch bark in differents conditions to improved the yield and the purity. Betulin has been known for a long time for its healing properties, most specifically for the treatment of skin diseases (eczema, psoriasis) 1. In previous studies 2 our group developed an efficient extraction method for betulin from white birch bark, with a high yield and purity (90%). The second aim was to obtain a highly hydrophobic and stable compound for biological tests as antineoplasic agent. MATERIALS AND METHODS Betulin was extracted from white birch bark, the solvents used was from Chimopar Bucureşti. Shortly chemical synthesis for esterification of betulin was performed in chloroform with fatty acid chlorides, reaction temperature 50°C in the presence of triethylamine (TEA). The reaction was monitorized by TLC (with silica gel plates), qualitative analysis of betulin and their esters was performed by FT-IR and MS spectroscopy and for the quantitative analysis HPLC technique was used. REFERENCES [1] Hänsel R, Keller K, Rimpler H, Schneider G: Drogen A-D: Betula. Berlin: Springer Verlag; 1992. [2] Dehelean C, Şoica C, Ledeţi I, Aluaş M, Zupko I, Gǎluşcan A, Cinta-Pinzaru S, Munteanu M, Study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation, Chemistry Central Journal 2012, 6:137. Fig. 2. FT-IR Spectra of betulin myristate with absorbtion band at 1737.78 cm -1 Fig. 3. HPLC chromatogram of betulin (blue, retention time 14.91), reaction mixture from betulin esterification (red, retention time 14.93 and 27.49) and betulin myristic acid ester (green, retention time 27.41 ) Fig. 1. UV-VIS absorption spectra of pure betulin (1), betulin crude extract (4,7,8) and purified betulin (2,3,5,6) RESULTS AND CONCLUSIONS Extraction of betulin in isopropanol media gave the best results and recrystallization from metanol led to pure betulin. Separation of esters was made by column chromatography using chloroform:diethyl ether (8:2), chloroform:ethyl acetate (6:4) and hexane:ethyl acetate (7:3) as eluents. Best results was achived with hexane:ethyl acetate. In the aforementioned conditions, only the diester of betulin was formed, as confirmed by HPLC (figure 3) and MS analysis.