Background: To date, many compounds extracted from natural products have anti-tumor activity, such as citronellol, ellagitannin-containing pomegranate extract, etc. Evidence from clinical context shows that multidrug resistance is an obstacle that impedes the effectiveness of natural products, such as chemotherapeutic agents, paclitaxel and vincristine. Overexpression of ATP- Binding Cassette (ABC) transporters is the leading cause of MDR. Therefore, it is crucial to investigate whether these natural products are substrates of MDR-associated ABC transporters, which may benefit the development of their clinical usage.

Objective: This review summarizes the latest insight on natural products possessing substrate profile and analyzes some possible directions for future drug discovery.

Conclusion: The anti-tumor effects of natural products are constantly being explored, but the drug resistance issues cannot be ignored, which limits their prospects as anti-tumor drugs to a certain extent. At the same time, some natural products are taken as a daily diet, and their possible role in increasing the drug resistance of the substrate should arouse the attention of clinical cancer patients.

背景：迄今为止，从天然产物中提取的许多化合物都具有抗肿瘤活性，例如香茅醇、含鞣花单宁的石榴提取物等。临床证据表明，多药耐药性是阻碍天然产物有效性的障碍，例如化疗药物，紫杉醇和长春新碱。ATP 结合盒 (ABC) 转运蛋白的过度表达是 MDR 的主要原因。因此，研究这些天然产物是否是 MDR 相关 ABC 转运蛋白的底物至关重要，这可能有利于其临床应用的发展。

目的：本综述总结了对具有底物特征的天然产物的最新见解，并分析了未来药物发现的一些可能方向。

结论：天然产物的抗肿瘤作用不断被探索，但耐药性问题不容忽视，在一定程度上限制了其作为抗肿瘤药物的前景。同时，一些天然产物作为日常饮食，其可能增加底物耐药性的作用应引起临床肿瘤患者的重视。