Rubesanolides F and G: Two Novel Lactone-Type Norditerpenoids from Isodon rubescens |
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| Authors: | Kang He Juan Zou Yu-Xue Wang Chen-Liang Zhao Jiang-Hai Ye Jing-Jie Zhang Lu-Tai Pan Hong-Jie Zhang |
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| Institution: | 1.The Key Laboratory of Miao Medicine of Guizhou Province, Guizhou University of Traditional Chinese Medicine, Guiyang 550025, China; (K.H.); (J.Z.); (Y.-X.W.); (C.-L.Z.); (J.-H.Y.); (J.-J.Z.);2.School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong, China |
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| Abstract: | A phytochemical investigation of the leaves of the medicinal plant Isodon rubescens led to the isolation of the two new degraded abietane lactone diterpenoids rubesanolides F (1) and G (2). Their structures were elucidated based on the analyses of the HRESIMS and 1D/2D NMR spectral data, and their absolute configurations were determined by ECD spectrum calculations and X-ray single crystal diffraction methods. Compounds 1 and 2, with a unique γ-lactone subgroup between C-8 and C-20, were found to form a carbonyl carbon at C-13 by removal of the isopropyl group in an abietane diterpene skeleton. Rubesanolide G (2) is a rare case of abietane that possesses a cis-fused configuration between rings B and C. The two isolates were evaluated for their biological activities against two cancer cell lines (A549 and HL60), three fungal strains (Candida alba, Aspergillus niger and Rhizopus nigricans) and three bacterial strains (Escherichia coli, Staphylococcus aureus and Bacillus subtilis). |
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| Keywords: | Isodon rubescens norditerpenoids ECD calculation single-crystal X-ray diffraction biological activities |
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