{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T13:17:10Z","timestamp":1790774230169,"version":"4.1.0"},"reference-count":33,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2024,4,26]],"date-time":"2024-04-26T00:00:00Z","timestamp":1714089600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Light Industry Technology and Engineering","award":["LITE2018-11"],"award-info":[{"award-number":["LITE2018-11"]}]},{"name":"Key Laboratory of Industrial Biotechnology (Jiangnan University, China), Ministry of Education, and the Key Laboratory of Carbohydrate Chemistry &amp; Biotechnology (Jiangnan University, China), Ministry of Education","award":["LITE2018-11"],"award-info":[{"award-number":["LITE2018-11"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>This study aimed to investigate the alkaloid secondary metabolites of Aspergillus amstelodami BSX001, a fungus isolated from Anhua dark tea, and to improve the extraction yield of the active ingredients by optimizing the extraction process. The structural characterization of the compounds was investigated using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. The antioxidant activity of echinulin-related alkaloids was evaluated by determining the total reducing power and DPPH radical scavenging capacity. The extraction process of the compound with optimum activity was optimized by a single-factor test and response surface methodology (RSM) combined with Box\u2013Behnken design (BBD). The optimized result was validated. Finally, a new alkaloid 8-hydroxyechinulin (1), and four known alkaloids, variecolorin G (2), echinulin (3), neoechinulin A (4), and eurocristatine (5), were isolated. Echinulin-related compounds 1, 3, and 4 possessed certain antioxidant activities, with IC50 values of 0.587 mg\/mL, 1.628 mg\/mL, and 0.219 mg\/mL, respectively, against DPPH radicals. Their total reducing power at a concentration of 0.5 mg\/mL was 0.29 mmol\/L, 0.17 mmol\/L, and 4.25 mmol\/L. The extraction process of neoechinulin A was optimized with the optimum extraction parameters of 72.76% methanol volume fraction, 25 mL\/g solid\u2013liquid ratio, and 50.8 \u00b0C soaking temperature. Under these conditions, the extraction yield of neoechinulin A was up to 1.500 mg\/g.<\/jats:p>","DOI":"10.3390\/microorganisms12050864","type":"journal-article","created":{"date-parts":[[2024,4,26]],"date-time":"2024-04-26T10:56:32Z","timestamp":1714128992000},"page":"864","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Isolation and Identification of Indole Alkaloids from Aspergillus amstelodami BSX001 and Optimization of Ultrasound-Assisted Extraction of Neoechinulin A"],"prefix":"10.3390","volume":"12","author":[{"given":"Shuyao","family":"Li","sequence":"first","affiliation":[{"name":"The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1865-4403","authenticated-orcid":false,"given":"Xiaobo","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiuya","family":"Gu","sequence":"additional","affiliation":[{"name":"The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaobin","family":"Yu","sequence":"additional","affiliation":[{"name":"The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"126043","DOI":"10.1016\/j.foodchem.2019.126043","article-title":"Microbial bioconversion of the chemical components in dark tea","volume":"312","author":"Zhu","year":"2020","journal-title":"Food Chem."},{"key":"ref_2","first-page":"454","article-title":"Research progress on Eurotium cristatum and its fermentation application","volume":"43","author":"Jiang","year":"2022","journal-title":"Shipin Gongye Keji"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Deng, J., Li, Y., Yuan, Y., Yin, F., Chao, J., Huang, J., Liu, Z., Wang, K., and Zhu, M. 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