Mushrooms have been widely used as health food and medicine, from which many kinds of bioactive compounds have been isolated.Recently, we found that the aqueous ethanol extract of bracket fungus Coriolus versicolor suppressed fat accumulation against 3T3-L1 murine adipocytes.Guided by this bioassay, a highly N-rnethylated cyclic heptapeptide (-)-tematin (1) has been isolated.This compound showed significant inhibitory effect of fat accumulation (EC50 =0.14 micro g/mL).The planar structure of 1 was determined to be cyclo [-Ile-(NMe)Ala-(NMe)Leu-Leu-(NMe)Ala-(NMe)Alabeta-OH-Leu-] by the analysis of 2D-NMR (COSY and HMBC) spectra.ROESY spectrum analysis of 1 and HPLC analysis of its hydrolyzed products confirmed the absolute stereochemistry of partial amino acids composed of 1.To confirm their stereochemistry, synthetic studies of (-)-tematin (1) were carried out.Fmoc-beta-OBn-D-Leu was prepared from isobutyraldehyde in 8 steps, followed by solid-phase peptide synthesis (SPPS) and cleavage of resin afforded linear heptapeptide.Cyclization and removement of Bn group gave cyclic heptapeptide stereoisomers 1 a-1 c.Comparison of 1H NMR data between natural and synthetic ternatin confirmed that the absolute stereochemistry of natural 1 was identical to that of 1c.Futher studies on the biological activities of ternatin are in progress.