ii new chitinase inhibitor, designated as argadin (1), a as isolated from t
he cultured broth of a fungal strain FO-7314, The strain was identified as
Clonostachys sp, from the morphological characteristics. Argadin was purifi
ed from the cultured mycelium by a combination of cation exchange, adsorpti
on and gel filtration chromatographic methods. The structure of argadin was
elucidated as cyclo(N-omega-acetyl-L-arginyl-D-prolyl-homoseryl-histidyl-L
-2-aminoadipyl) in which homoseryl gamma-methylene bonded to histidyl alpha
-amino residue. The IC50 value of argadin against Lucilia cuprina (blowfly)
chitinase was 150 nM at 37 degrees C and 3.4 nM at 20 degrees C. Argadin a
rrested the moult of cockroach larvae upon injection into the ventral abdom
inal part.