Abstract

Twenty-one known specialised metabolites were isolated from the flowers of Vernonanthura nudiflora (Less.) H. Rob., the structures of the compounds were established based on 1 D and 2 D NMR spectroscopic experiments. Others 28 compounds were putatively identified using the dereplication technique by UHPLC-HRMS/MS. Twenty-three of the compounds are being reported for the first time in this species. The mixture of sesquiterpene lactones piptocarphins A and B (17 + 18), and the flavone velutin (14) were tested against several microorganisms and showed promising activity against Mycobacterium tuberculosis with MIC of 15.6 μg/mL and 31.2 μg/mL, respectively. Furthermore, 17 + 18 showed greater cytotoxicity against VERO cells (IC₅₀ = 7.0 ± 1.73) compared to compound 14 (IC₅₀ 85.0 ± 10.6 µg/mL). These findings reveal the feasibility of using the UHPLC-ESI-HRMS/MS-based dereplication strategy in complex fractions to identify specialised metabolites, moreover to V. nudiflora flowers being a source of compounds with antimycobacterial potential.

摘要

从Vernonanthura nudiflora (Less.) H. Rob.的花中分离出 21 种已知的特殊代谢物，这些化合物的结构是基于 1 D 和 2 D NMR 光谱实验建立的。其他 28 种化合物通过 UHPLC-HRMS/MS 使用去复制技术推定鉴定。其中 23 种化合物是该物种中首次报道的。倍半萜内酯 piptocarphins A 和 B ( 17 + 18 ) 以及黄酮 velutin ( 14 ) 的混合物针对几种微生物进行了测试，并显示出对结核分枝杆菌的良好活性，MIC 分别为 15.6 μg/mL 和 31.2 μg/mL。此外，17 + 18与化合物14 (IC ₅₀ 85.0 ± 10.6 µg/mL)相比，对 VERO 细胞显示出更大的细胞毒性 (IC _{50 = 7.0 ± 1.73)。}这些发现揭示了在复杂组分中使用基于 UHPLC-ESI-HRMS/MS 的去复制策略来鉴定特殊代谢物的可行性，此外，裸花五花花是具有抗分枝杆菌潜力的化合物的来源。