Dimeric eremophilane-type sesquiterpenoids from the peeled stems of Syringa pinnatifolia

• Published in: Phytochemistry (Oxford) Vol. 221; p. 114048
• Main Authors: Sun, Jingjing, Li, Anni, Jiao, Shungang, Liu, Changxin, Zhang, Zefeng, Chen, Hongying, Liang, Yana, Gao, Xiaoli, Cao, Lan, Bai, Changcai, Chai, Xingyun
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.05.2024; Elsevier
• Subjects: Biochemistry & Molecular Biology; Cardioprotective activity; Eremophilane sesquiterpenoid dimers; Life Sciences & Biomedicine; Oleaceae; Plant Sciences; Science & Technology; Syringa pinnatifolia Hemsl; Syringenes; Syringenes; Oleaceae; Eremophilane sesquiterpenoid dimers; Syringa pinnatifolia Hemsl; Cardioprotective activity; NATURAL DISESQUITERPENOIDS; HEMSL
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2024.114048

A continued phytochemical investigation guided by 1H NMR and LC-MS data on the ethanol extract from the peeled stems of Syringa pinnatifolia Hemsl. led to the isolation of 16 undescribed dimeric eremophilane sesquiterpenoids, namely syringenes R–Z (1–9) and A1–G1 (10–16). These structures were elucidated by extensive analysis of spectroscopic data, including HRESIMS, NMR, quantum-mechanics-based computational analysis of NMR chemical shifts, and single-crystal X-ray diffraction analyses, and a concise rule for determination of relative configuration of angular methyl was proposed. The results of the cardioprotective assay demonstrated that 3 exhibits a protective effect against hypoxia-induced injuries in H9c2 cells. This effect was observed at a concentration of 10 μM, with a protective rate of 28.43 ± 11.80%. Sixteen undescribed dimeric eremophilane sesquiterpenoids were isolated from Syringa pinnatifolia. A concise rule for relative configuration of angle methyls of eremophilane dimers was proposed. [Display omitted] •Sixteen undescribed dimeric eremophilane sesquiterpenoids were isolated from Syringa pinnatifolia.•The absolute configurations were determined by analyzing its spectroscopic and single-crystal X-ray diffraction data.•A concise rule for relative configuration of angle methyls of eremophilane dimers was proposed.•Syringene T exhibits a protective effect against hypoxia-induced injuries in H9c2 cells.