Sideroxylin from Miconia Ioneura: Monohydrate Crystal Structure from High Resolution X-Ray Powder Diffraction

High resolution X-ray powder diffraction has been used to obtain the crystal structure of sideroxylin (4H-1-Benzopyran-4-one,5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-6,8-dimethyl) monohydrate, (C18H16O5).H2O, isolated from the bioactive ethyl acetate extract of Miconia ioneura Griseb (Melastomataceae) leaves. The crystal structure was determined using direct space methodology based on the simulated annealing algorithm. Thermogravimetric analysis shows that the material dehydrates while heated from room temperature to ~150°C.