Metflurazon

Metflurazon (SAN 6706) is a pro-herbicide that acts as a substrate for cytochrome P450 monooxygenase. Metflurazon undergoes sequential N-demethylation to form Norflurazon (HY-114849), which in turn exerts anti-cyanobacterial activity. Metflurazon inhibits cyclic photophosphorylation, growth, heterocyst formation, and exogenous ATP transport in cyanobacteria, reduces their survival rate, and induces a methylamine-like effect. Metflurazon can be used in studies related to herbicides and cyanobacteria^[1][2]. In Vitro:Metflurazon (14 h) inhibits cell volume growth in synchronized Chlorella fusca (EC₅₀ = 0.2 μM) and Chlorella sorokiniana (EC₅₀ = 4.6 μM) cultures, with Chlorella fusca being 25 to 80 times more sensitive to the compound^[1].
Metflurazon (25 μM; 30 min-2 h) undergoes N-demethylation to form Norflurazon (HY-114849) in Chlorella fusca (apparent K_m = 1.25 μM) and Chlorella sorokiniana (apparent K_m = 11.1 μM), with Chlorella fusca exhibiting 10-fold higher substrate affinity and ~2-fold higher demethylation activity across most of the cell cycle^[1].
Metflurazon (30-60 µM; 15 min) potently inhibits growth, heterocyst formation, and survival of wild-type Nostoc muscorum (Nm 01) with LD₅₀ values of 28.5 µM in Ncomb-free medium and 33.3 µM in NO₃⁻ medium, and these inhibitory effects are reversible by exogenous glucose or ATP supplementation^[2].
Metflurazon (3 mM; continuous exposure) resistant Nostoc muscorum (Nm 62) mutant exhibits a resistance factor of 130-160, maintains growth and nitrogen fixation (with ATP supplementation) in the presence of 3 mM Metflurazon, and displays cross-resistance to methylamine^[2].