New Azulene-Type Sesquiterpenoids from the Fruiting Bodies of Lactarius deliciosus

In the 1 H NMR-guided fractionation of extracts from the edible mushroom Lactarius deliciosus , two new azulene-type sesquiterpenoids, 7-isopropenyl-4-methyl-azulene-1-carboxylic acid ( 1 ) and 15-hydroxy-3,6-dihydrolactarazulene ( 2 ), together with seven known compounds were characterized. Their structures were determined on basis of spectroscopic evidence, as well as by comparing with literature data. Amongst the known metabolites, the 13 C NMR assignment of 15-hydroxy-6,7-dihydrolactarazulene ( 3 ) is reported here for the first time. Moreover, 7-acetyl-4-methylazulene-1-carbaldehyde ( 5 ) displayed a moderate antibacterial activity against Staphylococcus aureus . Graphical Abstract *Digital image of L. deliciosus. Retrieved March 17, 2017 from https://upload.wikimedia.org/wikipedia/commons/e/e3/Lactarius_deliciosus_1_(1).jpg .