Natural products (NPs) have been an important source of therapeutic drugs in clinic use and contributed many chemical probes for research. The usefulness of NPs is however often marred by the incomplete understanding of their direct cellular targets. A number of experimental methods for drug target identification have been developed over the years. One class of methods, termed “label-free” methodology, exploits the energetic and biophysical features accompanying the association of macromolecules with drugs and other compounds in their native forms. Herein we review the working principles, assay implementations, and key applications of the most important approaches, and also give examples where they have been applied to NPs. We also assess the key advantages and limitations of each method. Furthermore, we address when and how the label-free methodology can be particularly useful considering some of the unique features of NP chemistry and bioactivation.

天然产物 (NPs) 一直是临床使用的治疗药物的重要来源，并为研究贡献了许多化学探针。然而，对其直接细胞目标的不完全理解往往损害了 NPs 的有用性。多年来，已经开发了许多用于药物靶标识别的实验方法。一类被称为“无标记”方法的方法利用了大分子与药物和其他天然形式的化合物相关的能量和生物物理特征。在此，我们回顾了最重要方法的工作原理、分析实施和关键应用，并给出了它们已应用于 NP 的示例。我们还评估了每种方法的主要优点和局限性。此外，