Squamocin and benzyl benzoate, acaricidal components of Uvaria pauci-ovulata bark extracts

Annonaceae have been commonly described in traditional medicine as remedies against head lice and for their insecticidal properties. Acaricidal effects of Uvaria pauci-ovulata bark extracts were investigated on Dermatophagoides pteronyssinus, the European house dust mite, and compared with those of benzyl benzoate used as standard acaricidal compound. A dichloromethane extract was the most effective with an EC50 = 0.028 g/m2 after a 24 h period as compared with benzyl benzoate (EC50 = 0.06 g/m2). Bioassay-guided fractionation of this extract led to the isolation of benzyl benzoate and squamocin; this latter compound also had acaricidal properties (EC50 = 0.6 g/m2). Moreover, squamocin was shown to potentiate the activity of benzyl benzoate using the fractional effective concentration (FEC) method.