On the local anaesthetic action of propolis and some of its constituents.

An ethanolic propolis extract and some constituents isolated from propolis were tested on the cornea of the rabbit and of the mouse for local anaesthetic activity. Total anaesthesia was obtained with the total extract as well as with the compounds 5,7-dihydroxyflavanone (pinocembrin), 5-hydroxy-7-methoxyflavanone (pinostrobin) and with a mixture of caffeic acid esters. Each of these compounds was nearly thrice as potent as the total extract. Propoxypiperocaine which was tested for the purpose of comparison was still efficient in an almost 10-fold lower concentration. When applied subcutaneously, pinocembrin and the mixture of caffeic acid esters produced nearly the same anaesthesia as lidocaine.