1. The use of at least one compound of formula I wherein R1, R2, R3, R4 and R5 independently of one another mean a radical selected from - H, OH, OCOCH, O (CHCHO) H, wherein n = 1 to 20, halogen, an unbranched or branched alkyl group having from 1 to 20 carbon atoms, which optionally may be substituted by one or more OH groups, and / or may be interrupted by one or more groups selected from -O-, - (C = O) -, - (CO) O - and cyclohexyl, - an unbranched or branched O-alkyl group having from 1 to 20 carbon atoms, and in which R6 is pa a dical selected from an unbranched or branched alkyl group having from 1 to 20 carbon atoms, which optionally can be substituted by one or more OH groups, - (CHCHO) H, n = 1 to 20, as an antimicrobial active compound .2. The use according to claim 1 in cosmetic / pharmaceutical formulations, pharmaceuticals, food products, household chemical goods, plastic products, paper and / or paints, in particular in dentifrices or oral care products. 3. The use of claim 1 or 2 to improve conservation. 4. The use of at least one compound of formula I wherein R1, R2, R3, R4 and R5 independently mean a radical selected from —H, OH, OCOCH, O (CHCHO) H, wherein n = 1 to 20, halogen, an unbranched or branched alkyl group having from 1 to 20 carbon atoms, which optionally may be substituted by one or more OH groups, and / or may be interrupted by one or more groups selected from —O—, - (C = O) -, - (CO) O - and cyclohexyl, - an unbranched or branched O-alkyl group having from 1 to 20 carbon atoms, and in which R6 is pa hiccup selected iz linear or branched alkyl group having 1 to 20 carbon atoms, a cat1. Применение по меньшей мере одного соединения формулы Iв которой R1, R2, R3, R4 и R5 независимо друг от друга означают радикал, выбранный из- Н, OH, OCOCH, O(CHCHO)H, причем n=от 1 до 20, галогена,- неразветвленной или разветвленной алкильной группы, имеющей от 1 до 20 атомов углерода, которая по выбору может быть замещена одной или несколькими OH группами,
