Pseudomonas methanica KY4634 was found to produce 5-lipoxygenase inhibitor designated KF8940, MY12-62a and MY12-62c. The inhibitors were purified by solvent extraction, silica gel column chromatography, reversed-phase low pressure liquid chromatography and crystallization. The chemical structures of KF8940, MY12-62a and MY12-62c were determined to be 2-n-heptyl-4-hydroxyquinoline-N-oxide, 2-n-heptyl-4-hydroxyquinoline and 3-n-heptyl-3-hydroxy-1,2,3,4-tetrahydroquinoline-2,4-diore, respectively, on the basis of their physico-chemical properties. Among them, KF8940 was the most potent inhibitor. The compound inhibited 5-lipoxygenase of rat basophilic leukemia cells in a dose-dependent manner and the half maximal inhibitory concentration (IC,0) was 1.5 x 10 M. At this concentration, KF8940 did not inhibit bovine platelet 12-lipoxygenase and cyclooxygenase, and the IC,,0 values for these enzyme were 3.5 x 10-5 M and 1.7 x 10-4 M, respectively. The results indicated that KF8940 is a potent and selective inhibitor of 5-lipoxygenase. The IC50 value of MY12-62c for 5-lipoxygenase was 1.9 x 10 M and that of MY12-62a was 1.9 x 10-5M.Much attention has been focused on 5-lipoxygenase inhibitors as anti-asthmatic and anti-inflammatory agents since SAMUELSSON and co-workersl,2) showed that slow reacting substances of anaphylaxis (SRS-A), potent mediators generated during anaphylactic reaction, were oxidative products of arachidonate 5-lipoxygenase. The enzyme is mainly distributed in leukocytes3) and catalizes the oxygenation of arachidonic acid at C-5 position to produce 5-HPETE. The product can be either reduced enzymatically to its hydroxy derivative, 5-HETE, or transformed to the peptide LTs and LTB4. LTB4 was proposed to be implicated in inflammatory reactions because of its potent chemotactic activity4).Many compounds have recently been reported as 5-lipoxygenase inhibitors5-9) and some of them exhibited anti-asthmatic activities10,11). In the course of screening for lipoxygenase inhibitors from microbial origin, we found that Pseudomonas methanica KY4634 produced potent 5-lipoxygenase inhibitors. The compounds, designated KF8940, MY12-62a and MY12-62c, were isolated from the culture broth and their structures were determined. Among them, KF8940, 2-n-heptyl-4-hydroxyquinoline-N-oxide, was a potent and selective inhibitor of the enzyme. This manuscript describes the fermentation, isolation and purification, structural identification, and some biological properties of the inhibitors.

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Streptomyces gabonae KY2234 was found to produce a new compound, MY336-a, which bound to N-adrenergic receptor. The compound was isolated from the fermentation broth of KY2234. MY336-a showed a high affinity for the p-receptor, labeled with [3H]dihydroalprenolol in the membrane fractions of rat heart (~1-adrenergic receptor) or lung (,32-adrenergic receptor), whereas the compound bound very weakly to a-adrenergic receptor, labeled with [3H]dihydroergokryptine in rat brain. The inhibition constants (Ki) of the compound were 0.73 and 0.14 t

Heptyl-4-hydroxyquinoline-7V-oxide (KF8940), isolated from Pseudomonas methanica, was a potent and selective inhibitor of the arachidonate 5-lipoxygenase of rat basophilic leukemia (RBL-1) cells. Kinetic analysis indicated that the inhibitory mode was non competitive. The Ki value was 3.5x 10~7m. KF8940 also inhibited 12-lipoxygenase of bovine platelets in a noncompetitive manner, but with a Ki value of 7x 10~5m. Ionophore A23187-stimulated SRS

We quantitatively assayed the levels of cross-linked fibrin degradation products (D dimer) in plasma at 73 points in time in 32 patients with elevated fibrin/fibrinogen degradation products (FDP) in serum. The assay of FDP was performed on serum samples prepared in test tubes containing 5 U/ml thrombin (final concentration) by a method based on latex agglutination using antifibrinogen antibodies, and the levels of D dimer in plasma were determined by a newly developed latex immunoassay using monoclonal antibodies which do not cross-react with fibrinogen. 5 patients with chronic myelogenous leukemia (CML) had highly elevated FDP levels with normal levels of D dimer. Plasma samples from such patients with CML were treated with various concentrations of thrombin (2–10 U/ml) and after the removal of fibrin clots the levels of FDP in supernatants were assayed by the FDP assay procedure described above. The levels of FDP were normalized when plasma were treated with 10 U/ml thrombin. In 2 patients with CML who had elevated levels of FDP in serum, it was impossible to remove fibrinogen completely by addition of 5 U/ml thrombin. However, FDP levels in the sera treated with 5 U/ml thrombin were almost normal in normal controls and patients with other diseases than CML. From these results it is concluded that residual fibrinogen reacted in the assay procedure as markedly increased FDP in supernatants and elevated FDP levels in serum reflected fibrinogen-related materials, which may not completely polymerize in the presence of lower concentrations of thrombin in some patients with CML. The assay of D dimer in plasma using monoclonal antibodies is recommended in cases of CML to rule out disseminated intravascular coagulation.