Isolation, biological activity, and synthesis of isoquinoline alkaloids

-based heterocyclic compounds, have attracted considerable attention from researchers worldwide. To follow up on our prior review (covering 2014-2018) and present the progress of this class of compounds, this review summarizes and provides updated literature on novel isoquinoline alkaloids isolated during the period of 2019-2023, together with their biological activity and underlying mechanisms of action. Moreover, with the rapid development of synthetic modification strategies, the synthesis strategies of isoquinoline alkaloids have been continuously optimized, and the total synthesis of these classes of natural products is reviewed critically herein. Over 250 molecules with a broad range of bioactivities, including antitumor, antibacterial, cardioprotective, anti-inflammatory, neuroprotective and other activities, are isolated and discussed. The total synthesis of more than nine classes of isoquinoline alkaloids is presented, and thirteen compounds constitute the first total synthesis. This survey provides new indications or possibilities for the discovery of new drugs from the original naturally occurring isoquinoline alkaloids.