Biotransformation of Patchouli Alcohol by Cladosporium cladosporioides and the Anti-Influenza Virus Activities of Biotransformation Products.

The biotransformation of patchouli alcohol by Cladosporium cladosporioides afforded 31 products, including 21 new ones ( 1 - 3 , 5 , 6 , 8 - 14 , and 17 - 25 ). Their structures were determined by extensive spectroscopic data analysis ( 1 H and 13 C NMR, HSQC, HMBC, 1 H- 1 H COSY, ROESY, and HRESIMS), and the absolute configuration of compounds 1 , 2 , 8 , 9 , and 17 was determined by single-crystal X-ray diffraction using Cu Kα radiation. Structurally, compounds 21-24 were patchoulol-type norsesquiterpenoids without Me-12. Among them, a Δ 3(4) double bond existed in compounds 21 and 22 ; a three-membered ring was formed between C-4, C-5, and C-6 in compound 23 ; an epoxy moiety appeared between C-3 and C-4 in compound 24 . Furthermore, the biotransformation products 9 , 10 , 12, and 25 showed potent anti-influenza virus activity with EC 50 values of 2.11, 7.94, 20.87, and 3.45 μ M, respectively.