Three New <i>Ent</i>-Kaurane Diterpenes with Antibacterial Activity from <i>Sigesbeckia orientalis</i>
Zhong-Shun Zhou,
Zhao-Jie Wang,
Bei Tian,
Yan-Yan Zhu,
Mei-Zhen Wei,
Yun-Li Zhao,
Xiao-Dong Luo
Affiliations
Zhong-Shun Zhou
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Zhao-Jie Wang
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Bei Tian
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Yan-Yan Zhu
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Mei-Zhen Wei
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Yun-Li Zhao
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Xiao-Dong Luo
Yunnan Characteristic Plant Extraction Laboratory, Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education and Yunnan Province, School of Chemical Science and Technology, Yunnan University, Kunming 650091, China
Three novel ent-kaurane diterpenes, namely sigesbeckin A–C (1–3), in conjunction with eight previously identified analogues (4–11), were isolated from Sigesbeckia orientalis. Their chemical structures were resolved through multiple spectroscopic analyses. All compounds were assessed for antimicrobial bioactivity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains. In particular, compounds 1 and 5 demonstrated moderate efficacy, with MIC values of 64 μg/mL. Moreover, compounds 3, 5, and 11 were found to synergize with doxorubicin hydrochloride (DOX) and vancomycin (VAN) against MRSA and VRE. The aforementioned findings offer valuable insights for the development of novel alternatives to antibiotics, which can effectively tackle the escalating issue of antibiotic resistance.
