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  2. Terpenoids with α-glucosidase inhibitory activity from Rhododendron minutiflorum Hu

Terpenoids with α-glucosidase inhibitory activity from Rhododendron minutiflorum Hu

  • Phytochemistry. 2022 Apr;196:113083. doi: 10.1016/j.phytochem.2021.113083.
Xian-Zhe Fan 1 Yang-Li Zhu 1 Rong-Wen Yuan 1 Li Deng 1 Cheng Hou 1 Wei Li 1 Ting Liu 1 Xiang-Qian Kong 2 Li-Jun Zhang 3 Hai-Bing Liao 4
Affiliations

Affiliations

  • 1 State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004, People's Republic of China.
  • 2 Center for Chemical Biology and Drug Discovery, GuangZhou Institutes of Biomedicine and Health, Chinese Academy of Science, Guangzhou, 510530, People's Republic of China.
  • 3 State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004, People's Republic of China. Electronic address: ajun840618@mailbox.gxnu.edu.cn.
  • 4 State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004, People's Republic of China. Electronic address: lhbing188@163.com.
Abstract

Five undescribed triterpenoids, two unusual omphalane-type sesquiterpenoids together with twenty-five known compounds were isolated from the leaves and stems of Rhododendron minutiflorum Hu. The absolute configurations of 1-3 and 6 were established by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). Compounds 6-7 feature the rare omphalane-type sesquiterpene skeleton and are verified by single-crystal X-ray diffraction analysis for the first time. In the biological activity assay, most of the triterpenoids have different degrees of inhibitory effects on α-glucosidase, with IC50 values ranging from 6.97 to 229.3 μM (the positive control drug acarbose has an IC50 value of 3.07 × 10-3 μM). Structure and activity relationship (SAR) study reveals that the oxidation degrees of C-3, C-8, or C-11 to C-13 of the ursane-type triterpenoid influence the inhibitory activity dramatically.

Keywords

Dammarane-type triterpenoid; Ericaceae; Omphalane-type sesquiterpenoid; Rhododendron minutiflorum Hu; Ursane-type triterpenoid; α-glucosidase inhibitory activity.

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