New cyclic sulfides, garlicnins I 2 , M, N, and O, from Allium sativum

One atypical thiolane-type sulfide, garlicnin I 2 ( 1 ), two 3,4-dimethylthiolane-type sulfides, garlicnins M ( 2 ) and N ( 3 ), and one thiabicyclic-type sulfide, garlicnin O ( 4 ), were isolated from the acetone extracts of Chinese garlic bulbs, Allium sativum and their structures were characterized. Hypothetical pathways for the production of the respective sulfides were discussed.