{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,17]],"date-time":"2026-05-17T00:18:37Z","timestamp":1778977117764,"version":"3.51.4"},"reference-count":28,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2018,11,16]],"date-time":"2018-11-16T00:00:00Z","timestamp":1542326400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2018R1A2B2006879"],"award-info":[{"award-number":["2018R1A2B2006879"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100005970","name":"Deutsche Stiftung f\u00fcr Herzforschung","doi-asserted-by":"publisher","award":["CRC1127 ChemBioSys and BE 4799\/3-1"],"award-info":[{"award-number":["CRC1127 ChemBioSys and BE 4799\/3-1"]}],"id":[{"id":"10.13039\/501100005970","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Ministry of Trade, Industry &amp; Energy (MOTIE, Korea)","award":["20000105, Development of Cosmeceutical Material Platform using Organo-Nano Complexes based on Natural Active Compounds"],"award-info":[{"award-number":["20000105, Development of Cosmeceutical Material Platform using Organo-Nano Complexes based on Natural Active Compounds"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In 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\u2013C (compounds 1\u20133). 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\u20133) 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\u2019s 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.<\/jats:p>","DOI":"10.3390\/molecules23113003","type":"journal-article","created":{"date-parts":[[2018,11,16]],"date-time":"2018-11-16T11:48:31Z","timestamp":1542368911000},"page":"3003","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Natalenamides A\u2013C, Cyclic Tripeptides from the Termite-Associated Actinomadura sp. RB99"],"prefix":"10.3390","volume":"23","author":[{"given":"Seoung Rak","family":"Lee","sequence":"first","affiliation":[{"name":"School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dahae","family":"Lee","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jae Sik","family":"Yu","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ren\u00e9","family":"Benndorf","sequence":"additional","affiliation":[{"name":"Leibniz Institute for Natural Product Research and Infection Biology\u2014Hans-Kn\u00f6ll-Institute, Beutenbergstra\u00dfe 11a, 07745 Jena, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4187-2177","authenticated-orcid":false,"given":"Sullim","family":"Lee","sequence":"additional","affiliation":[{"name":"College of Bio-Nano Technology, Gachon University, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dong-Soo","family":"Lee","sequence":"additional","affiliation":[{"name":"College of Korean Medicine, Gachon University, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jungmoo","family":"Huh","sequence":"additional","affiliation":[{"name":"College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Gwanak-gu, Seoul 08826, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9758-8987","authenticated-orcid":false,"given":"Z. Wilhelm","family":"De Beer","sequence":"additional","affiliation":[{"name":"Forestry and Agriculture Biotechnology Institute, University of Pretoria, Pretoria 0028, South Africa"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yong Ho","family":"Kim","sequence":"additional","affiliation":[{"name":"SKKU\u2014Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9747-3423","authenticated-orcid":false,"given":"Christine","family":"Beemelmanns","sequence":"additional","affiliation":[{"name":"Leibniz Institute for Natural Product Research and Infection Biology\u2014Hans-Kn\u00f6ll-Institute, Beutenbergstra\u00dfe 11a, 07745 Jena, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ki Sung","family":"Kang","sequence":"additional","affiliation":[{"name":"College of Korean Medicine, Gachon University, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5285-9138","authenticated-orcid":false,"given":"Ki Hyun","family":"Kim","sequence":"additional","affiliation":[{"name":"School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,11,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1021\/acs.jnatprod.5b01055","article-title":"Natural products as sources of new drugs from 1981 to 2014","volume":"79","author":"Newman","year":"2016","journal-title":"J. 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