NMR Center, Department of Chemistry, Federal University of Paraná, 81530-900, Curitiba, PR, Brazil.
NMR Center, Department of Chemistry, Federal University of Paraná, 81530-900, Curitiba, PR, Brazil; Núcleo de Estudos Químicos de Micromoléculas da Amazônia - NEQUIMA, Federal University Amazonas, Manaus, Amazonas, Brazil.
J Pharm Biomed Anal. 2020 May 30;184:113200. doi: 10.1016/j.jpba.2020.113200. Epub 2020 Feb 24.
Baccharis trimera is a species recognized by health agencies and recommended by the Brazilian Pharmacopoeia by having medicinal properties. In this work, HR-MAS NMR spectroscopy combined with chemometric tools, such as Principal Components Analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA) and Soft Independent Modeling by Class Analogy (SIMCA), were used to evaluate the quality control and authenticity of commercial samples of Baccharis, as well as to discriminate B. trimera samples from other species of the Caulopterae section (B. articulata, B. trimera, B. junciformis, B. milleflora, and B. myriocephala). The high morphological similarity of these species makes it difficult for their identifications and discriminations, even by taxonomists. Different PCA pre-processing (autoscaling, Pareto scaling, and mean centering) allowed to discriminate B. trimera and B. myriocephala from the other species, mainly due to the presence of carquejyl acetate, indicated their chemical similarity. The H HR-MAS NMR spectral profile offers the possibility of tracking not only the chemical markers, such as the presence of carquejyl acetate, which can also be helpful in the B. trimera authentication/identification. The application of classification methods in standard samples revealed that PLS-DA models showed better performance on the calibration and validation sets than SIMCA model. However, PLS-DA and SIMCA applied to commercial samples showed that none of the commercial samples were classified as B. trimera, which suggested the lack of strict quality control regarding these products. The methodology developed in the present work might contribute to chemotaxonomy of the genus Baccharis.
Baccharis trimera 是一种被健康机构认可并被巴西药典推荐具有药用特性的物种。在这项工作中，高分辨魔角旋转核磁共振（HR-MAS NMR）光谱结合化学计量学工具，如主成分分析（PCA）、偏最小二乘判别分析（PLS-DA）和软独立建模分类分析（SIMCA），被用于评估 Baccharis 的商业样品的质量控制和真实性，以及区分 Baccharis trimera 样品与其他 Caulopterae 节（B. articulata、B. trimera、B. junciformis、B. milleflora 和 B. myriocephala）的物种。这些物种的形态高度相似，使得即使是分类学家也难以识别和区分它们。不同的 PCA 预处理（自动缩放、Pareto 缩放和中心化）允许区分 Baccharis trimera 和 B. myriocephala 与其他物种，主要是由于 carquejyl 乙酸酯的存在，表明它们具有化学相似性。高分辨魔角旋转核磁共振（HR-MAS NMR）光谱谱图提供了不仅跟踪化学标志物（如 carquejyl 乙酸酯的存在）的可能性，而且还可以帮助 Baccharis trimera 的鉴定/识别。分类方法在标准样品中的应用表明，PLS-DA 模型在校准集和验证集上的性能优于 SIMCA 模型。然而，PLS-DA 和 SIMCA 应用于商业样品表明，没有一个商业样品被分类为 Baccharis trimera，这表明这些产品缺乏严格的质量控制。本工作中开发的方法可能有助于 Baccharis 属的化学分类学。
