Mictobial transformation of some natural aromatic substances and their biological effects

Derivatives of natural and aromatic compounds obtained by biotransformation constitute an important resource for natural pharmaceutical, fragrance and aroma substances. In this present work the monoterpene ?-phellandrene and the essential oil of Schinus molle L. (Anacardiaceae) containing this constituent as major compound were biotransformed by 22 different microorganisms (bacteria, fungi and yeasts). 10 metabolites were characterized by spectroscopic methods, where 6-hydroxypiperitone, ?-phellandrene epoxide, cis-p-menth-2-en-1-ol and carvotanacetone originated from (R)-(-)-?-phellandrene were reported for the first time in this study. Furthermore, individual biotransformation studies with the major essential oil constituents limonene and ?-phellandrene obtained from commercial sources yielded 8-p-menthen-1,2-diol and 5-p-menthen-1,2-diol. Also substrates and metabolites were subjected to in vitro antibacterial, anticandidal and acute toxicity test (bioluminescent Vibrio fischeri). The biotransformation metabolite 8-p-menten-1,2-diol from limonene showed inhibitory activity towards the pathogens Bacillus cereus and methicilline resistant Staphylococcus aureus (MRSA) better than the substrate and the standard antimicrobial ampicilline. The metabolite 5-p-menthen-1,2-diol obtained from the substrate ?-phellandrene showed also good inhibitory activities against various bacteria and Candida species with relatively non-toxic properties detected by the Vibrio fischeri bioluminescence assay.Only a few studies on the biotransformation of essential oils were conducted according to the literature search, where this work is the first example for Turkey.Key words: Schinus molle, essential oil, ?-phellandren, biotransformation, bioassays