New Helvolic Acid Derivatives with Antibacterial Activities from Sarocladium oryzae DX-THL3, an Endophytic Fungus from Dongxiang Wild Rice (Oryza rufipogon Griff.) |
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| Authors: | Zhi-Bin Zhang Si-Yao Du Bo Ji Chang-Jiu Ji Yi-Wen Xiao Ri-Ming Yan Du Zhu |
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| Institution: | 1.Key Laboratory of Protection and Utilization of Subtropical Plant Resources of Jiangxi Province, College of Life Science, Jiangxi Normal University, Nanchang 330022, China; (Z.-B.Z.); (S.-Y.D.); (Y.-W.X.); (R.-M.Y.);2.College of Life Science, Jiangxi Science and Technology Normal University, Nanchang 330013, China;3.College of Chemistry and Biological Engineering, Yichun University, Yichun 336000, China |
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| Abstract: | Three new helvolic acid derivatives (named sarocladilactone A (1), sarocladilactone B (2) and sarocladic acid A (3a)), together with five known compounds (6,16-diacetoxy-25-hy- droxy-3,7-dioxy-29-nordammara-1,17(20)-dien-21-oic acid (3b), helvolic acid (4), helvolinic acid (5), 6-desacetoxy-helvolic acid (6) and 1,2-dihydrohelvolic acid (7)), were isolated from the endophytic fungus DX-THL3, obtained from the leaf of Dongxiang wild rice (Oryza rufipogon Griff.). The structures of the new compounds were elucidated via HR-MS, extensive 1D and 2D NMR analysis and comparison with reported data. Compounds 1, 2, 4, 5, 6 and 7 exhibited potent antibacterial activities. In particular, sarocladilactone B (2), helvolinic acid (5) and 6-desacetoxy-helvolic acid (6) exhibited strongly Staphylococcus aureus inhibitory activity with minimum inhibitory concentration (MIC) values of 4, 1 and 4 μg/mL, respectively. The structure–activity relationship (SAR) of these compounds was primarily summarized. |
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| Keywords: | endophytic fungus Sarocladium oryzae helvolic acid derivatives antibacterial activity SAR |
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