New 36-membered polyol macrolides deplelides A and B were isolated from the culture of Streptomyces MM581-NF15 by bioassay-guided fractionation using an ATP depletion assay. The planar structures of these novel compounds were identified by interpretation of the spectroscopic data (1D/2D NMR, MS, and IR). The relative stereochemistry was partially established using the universal NMR database method and J-based configuration analysis using H-H and long-range H-C coupling constants determined by H NMR or E.COSY and J-resolved HMBC analysis or another HMBC-based technique, respectively. The absolute stereochemistry was partially determined by a modified Mosher's method. These new compounds displayed highly potent ATP depletion activities (IC 33 nM) and antiproliferative activities against several tumor cell lines, such as HGC-27 (IC 47 nM).

Two new 4'-acetylated analogs of chrysomycin were discovered during the screening for antitumor agents from the metabolites of actinomycetes. Their structures and physicochemical properties were determined by standard spectrometric analyses. Their cytotoxicities and antimicrobial activities were evaluated against a panel of cancer cell lines and microbes. While acetylation reinforced the cytotoxicity of chrysomycin B, it weakened the activity of chrysomycin A. Chrysomycin A and its acetylated analog showed high cytotoxicity toward most of the cancer cells with ICs less than 10 ng ml. The 4'-acetyl-chrysomycin A was predominantly observed in nuclei at concentrations where the autofluorescence was observable. Chrysomycins were effective toward Gram-positive bacteria. The 4'-acetylated-chrysomycin A and B had MICs of 0.5-2 μg ml and 2 to greater than 64 μg ml, respectively, toward Gram-positive bacteria including MRSA and VRE.

Nonreducing disaccharide trehalose is used as a stabilizer and humectant in various products and is a potential medicinal drug, showing curative effects on the animal models of various diseases. However, its use is limited as it is hydrolyzed by trehalase, a widely expressed enzyme in multiple organisms. Several trehalose analogs are prepared, including a microbial metabolite 4‐trehalosamine, and their high biological stability is confirmed. For further analysis, 4‐trehalosamine is selected as it shows high producibility. Compared with trehalose, 4‐trehalosamine exhibits better or comparable protective activities and a high buffer capacity around the neutral pH. Another advantage of 4‐trehalosamine is its chemical modifiability: simple reactions produce its various derivatives. Labeled probes and detergents are synthesized in one‐pot reactions to exemplify the feasibility of their production, and their utility is confirmed for their respective applications. The labeled probes are used for mycobacterial staining. Although the derivative detergents can be effectively used in membrane protein research, long‐chain detergents show 1000–3000‐fold stronger autophagy‐inducing activity in cultured cells than trehalose and are expected to become a drug lead and research reagent. These results indicate that 4‐trehalosamine is a useful trehalose substitute for various purposes and a material to produce new useful derivative substances.

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