Natalenamides A–C, Cyclic Tripeptides from the Termite-Associated Actinomadura sp. RB99
AbstractIn recent years, investigations into the biochemistry of insect-associated bacteria have increased. When combined with analytical dereplication processes, these studies provide a powerful strategy to identify structurally and/or biologically novel compounds. Non-ribosomally synthesized cyclic peptides have a broad bioactivity spectrum with high medicinal potential. Here, we report the discovery of three new cyclic tripeptides: natalenamides A–C (compounds 1–3). These compounds were identified from the culture broth of the fungus-growing termite-associated Actinomadura sp. RB99 using a liquid chromatography (LC)/ultraviolet (UV)/mass spectrometry (MS)-based dereplication method. Chemical structures of the new compounds (1–3) were established by analysis of comprehensive spectroscopic methods, including one-dimensional (1H and 13C) and two-dimensional (1H-1H-COSY, HSQC, HMBC) nuclear magnetic resonance spectroscopy (NMR), together with high-resolution electrospray ionization mass spectrometry (HR-ESIMS) data. The absolute configurations of the new compounds were elucidated using Marfey’s analysis. Through several bioactivity tests for the tripeptides, we found that compound 3 exhibited significant inhibitory effects on 3-isobutyl-1-methylxanthine (IBMX)-induced melanin production. The effect of compound 3 was similar to that of kojic acid, a compound extensively used as a cosmetic material with a skin-whitening effect. View Full-Text
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Lee, S.R.; Lee, D.; Yu, J.S.; Benndorf, R.; Lee, S.; Lee, D.-S.; Huh, J.; de Beer, Z.W.; Kim, Y.H.; Beemelmanns, C.; Kang, K.S.; Kim, K.H. Natalenamides A–C, Cyclic Tripeptides from the Termite-Associated Actinomadura sp. RB99. Molecules 2018, 23, 3003.
Lee SR, Lee D, Yu JS, Benndorf R, Lee S, Lee D-S, Huh J, de Beer ZW, Kim YH, Beemelmanns C, Kang KS, Kim KH. Natalenamides A–C, Cyclic Tripeptides from the Termite-Associated Actinomadura sp. RB99. Molecules. 2018; 23(11):3003.Chicago/Turabian Style
Lee, Seoung R.; Lee, Dahae; Yu, Jae S.; Benndorf, René; Lee, Sullim; Lee, Dong-Soo; Huh, Jungmoo; de Beer, Z. W.; Kim, Yong H.; Beemelmanns, Christine; Kang, Ki S.; Kim, Ki H. 2018. "Natalenamides A–C, Cyclic Tripeptides from the Termite-Associated Actinomadura sp. RB99." Molecules 23, no. 11: 3003.
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