Microbial transformation of kawain and methysticin

The styryl alpha -pyrones, d-kawain (1) and d-methysticin (2) are two of th e major kavalactone constituents of the anxiolytic herb Piper methysticum, commonly known as kava. The use of fungal models to mimic the mammalian met abolism of I resulted in the production of 4'-hydroxykawain (1a) from the c ulture broth of Cunninghamella elegans (ATCC 9245), the same metabolite ide ntified in rat urine. The fungus Torulopsis petrophilum (ATCC 20225) biotra nsformed 2 to 3'-hydroxy-4'-methoxykawain (2c), which is analogous, but not identical, to a known rat metabolite of methysticin.