• Questiomycin A packaged and labeled in glass vial.

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SKU: Q004

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Questiomycin A is a phenoxazine produced by several Streptomyces species and some fungi and bacteria. Questiomycin A is weakly active against bacteria, fungi, plants and tumor cell lines, and inhibits aromatase and sulfatases. More recently, questiomycin A has been shown to inhibit pulmonary metastasis caused by mouse melanoma cells. Questiomycin A and related phenoxazines are important dereplication standards in discovery research to eliminate leads due to high amounts of weakly potent actives.

Questiomycin A is soluble in ethanol, methanol, DMF and DMSO.

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    Mechanism of Action

    Questiomycin stimulates cell growth and turnover in vitro, an activity possibly related to their ability to form stable free radicals.

    Storage Conditions




    Red to red brown solid



    The new antibiotics, questiomycins A and B. Anzai K. et al. J. Antibiot. 1960, 13, 125.

    Studies on cell growth stimulating substances of low molecular weight. Imai S. et al. J. Antibiot. 1993, 46, 1232.

    2-Aminophenoxazine-3-one prevents pulmonary metastasis of mouse B16 melanoma cells in mice. Hongo T. J. Pharmacol. Sci. 2010, 114, 63.

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