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.