New natural products, mangromicins, from Lechevalieria aerocolonigenes K10-0216

Staurosporine¹⁾ was found from culture broth of an actinomycete using an approach based on Physicochemical Screening (PCS) by our group. As PCS is a search method for new compounds utilizing the physico-chemical properties of compounds, such as polarity, molecular formula and UV spectra, this screening method does not depend on biological activity. The search for new compounds via this screening system is guided by liquid chromatography-UV detection (LC/UV), liquid chromatography-MS (LC/MS), and color reaction (for example, detection of alkaloids by Dragendorff’s reagent). We have discovered new compounds mangromicin analogs, A-I, from a cultured broth of Lechevalieria aerocolonigenes K10-0216 possesing unique structure.^2-4) Mangromicins are an unprecedented structural skeleton of a cyclopentadecane with a 5,6-dihydro-4-hydroxy-2-pyrone moiety and a tetrahydrofuran unit except mangromicin C including a tetrahydropyran unit. In the biological activities, mangromicins showed radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and nitric oxide generated from LPS-stimulated RAW264.7 cells, a murine macrophage cell line. Among the analogs, mangromicins A and I showed the most potent DPPH radical scavenging activity and nitric oxide scavenging activity, respectively.

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