Monoterpene Indole Alkaloid-Like Compounds Based on Diversity-Enhanced Extracts of Iridoid-Containing Plants and Their Immune Checkpoint Inhibitory Activity

A library of iridoid-conjugated indole alkaloid-like compounds was constructed from diversity-enhanced extracts, which constitutes an approach for increasing the chemical diversity of natural-product-like compounds by combining natural product chemistry and diversity-oriented synthesis. Pharmacological screening of the library revealed a seed compound that can be used for the development of small molecular immune checkpoint inhibitors.