Research progress of natural products targeting tumor-associated macrophages in antitumor immunity: A review

As an important innate immune cell in the body, macrophages have a strong ability to phagocytic tumor cells and maintain the innate immune response. Tumor-associated macrophages play a more prominent role in regulating tumor immunity and are currently an important target of antitumor immunity. As a new type of antitumor therapy, tumor immunotherapy has great potential, combined chemotherapy, targeting and other therapeutic means can significantly enhance the antitumor therapy effect. At present, a number of natural products have been proved to have significant immunomodulatory and antitumor effects, and have become a hot field of antitumor immunity research. Studies have found that a variety of natural products, such as polysaccharides, flavonoids, saponins, lactones, and alkaloids, can induce the polarization of M1 macrophages, inhibit the polarization of M2 macrophages, and regulate the expression of immune-related cytokines by targeting specific signaling pathways to enhance the killing effect of macrophages on tumor cells and improve the tumor immune microenvironment, and finally better play the antitumor immune function. In this paper, by summarizing the research results of the specific mechanism of natural products targeting tumor-associated macrophages to exert antitumor immunity in recent years, we discussed the aspects of natural products targeting tumor-associated macrophages to enhance antitumor immunity, in order to provide a new research idea for tumor immunotherapy and further improve the effectiveness of clinical antitumor therapy.