Acaricidal activity of Uvaria versicolor and Uvaria Klaineana (Annonaceae).

Three Uvaria species, namely U. klaineana, U. mocoli and U. versicolor were tested in vitro against Dermatophagoides pteronyssinus, the European house dust mite. The most active extracts were the Uvaria versicolor stems crude methanol and hexane extracts with EC(50) values of 0.095 g/m(2 )and 0.12 g/m(2), respectively. The bioassay-guided fractionation of the hexane extract led to the isolation of benzyl benzoate (1). which exhibited an EC(50) value of 0.045 g/m(2). A new fl avanone, versuvanone (2). and the known oxoaporphine liriodenine (3). were also isolated from this species and showed EC(50) values > 1.5 g/m(2). A weak acaricidal activity (0.85 g/m(2)) was observed for the dichloromethane extract of Uvaria klaineana, due to the presence of benzyl benzoate. Uvaria mocoli was inactive. The structures of compounds were elucidated using 2D-NMR techniques.