Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, Brazil.
Institute of Chemistry, Federal University of Alfenas, Alfenas, Brazil.
Phytochem Anal. 2021 Nov;32(6):891-898. doi: 10.1002/pca.3032. Epub 2021 Feb 8.
Casearia is an essential source of cytotoxic highly oxidised clerodane diterpenes, in addition to phenolics, flavonoids, and glycoside derivatives. Here we identify flavonoid-3-O-glycoside derivatives in the ethyl acetate (EtOAc) fraction of the methanolic extract from leaves C. arborea leaves.
To characterise the EtOAc phase from the methanolic extract of C. arborea leaves using ultra-high-performance liquid chromatography diode array detector high-resolution tandem mass spectrometry (UHPLC-DAD-HRMS/MS) and molecular networking-based dereplication. Methodology We identified compounds not annotated in the GNPS platform by co-injection of standards in HPLC-DAD or by isolation and characterisation of the metabolites using nuclear magnetic resonance (NMR) spectroscopy. A workflow on the GNPS platform aided the organisation of spectral data and dereplication by annotations. We subjected the EtOAc phase to HPLC-DAD analysis using standard compound co-injection to corroborate the GNPS annotations. We isolated unidentified compounds with semi-preparative HPLC-DAD for structural identification using NMR.
We annotated a molecular family of flavonoid-3-O-glycosides in the molecular networking created using the GNPS platform. These included avicularin, cacticin, isoquercitrin, quercitrin, rutin, and a quercetin-3-O-pentoside cluster. We confirmed the annotations with standard compounds using HPLC-DAD co-injection analysis, besides identifying quercetin-3-O-robinobioside and kaempferol. We isolated three flavonoid-3-O-pentosides and characterised them using one- and two-dimensional NMR; we identified them as reynoutrin, guaijaverin, and avicularin.
This work describes the isolation of kaempferol and nine known flavonoid-3-O-glycosides from the polar fraction of the methanolic extract (EtOAc) from C. arborea leaves using molecular networking to guide the chromatographic procedures. We identified eight compounds for the first time in Casearia that amplify and reinforce the genus' chemotaxonomy with the presence of glycosylated flavonoids.
山黄皮是细胞毒性高度氧化的 clerodane 二萜类化合物的重要来源，此外还有酚类、类黄酮和糖苷衍生物。在这里，我们在山黄皮叶甲醇提取物的乙酸乙酯（EtOAc）部分中鉴定出黄酮类 3-O-糖苷衍生物。
使用超高效液相色谱二极管阵列检测器高分辨串联质谱（UHPLC-DAD-HRMS/MS）和基于分子网络的去重复鉴定来表征山黄皮叶甲醇提取物的 EtOAc 相。
我们通过在 HPLC-DAD 中共同注入标准品或通过使用核磁共振（NMR）光谱对代谢物进行分离和表征来鉴定在 GNPS 平台上未注释的化合物。GNPS 平台上的工作流程有助于组织光谱数据和通过注释进行去重复鉴定。我们使用标准化合物共注入对 EtOAc 相进行 HPLC-DAD 分析，以证实 GNPS 注释。我们使用半制备 HPLC-DAD 分离未鉴定的化合物，并用 NMR 进行结构鉴定。
我们在使用 GNPS 平台创建的分子网络中注释了黄酮类 3-O-糖苷的分子家族。其中包括白杨素、芹菜素、异槲皮苷、槲皮苷、芦丁和槲皮素-3-O-戊糖苷簇。我们使用 HPLC-DAD 共注入分析用标准化合物证实了这些注释，此外还鉴定了槲皮素-3-O-鼠李糖苷和山柰酚。我们分离了三种黄酮类 3-O-戊糖苷，并使用一维和二维 NMR 对其进行了表征；我们将它们鉴定为瑞香素、芫花素和白杨素。
本工作描述了使用分子网络指导色谱程序从山黄皮叶甲醇提取物（EtOAc）的极性部分中分离出山柰酚和九种已知的黄酮类 3-O-糖苷。我们首次在山黄皮中鉴定出八种化合物，这些化合物增强了该属的化学分类学，因为它们含有糖基化的类黄酮。
