Recent Research Progress on the Origin, Biological Activities, and Synthesis of Natural Bibenzyls

Bibenzyls are aromatic compounds widely found in numerous plants with diverse structures and remarkable biological activities such as antioxidant, antitumor, antibacterial, anti-inflammatory, and neuroprotective activities. Bibenzyls can be classified into six categories according to their chemical structure: simple bibenzyls, carbon-bridge-substituted bibenzyls, prenylated bibenzyls, bibenzyl glycosides, bis-bibenzyls, and others. In addition, bibenzyls are generally extracted from plants by physical and chemical methods with low yields, which significantly limit their development and utilization. This review presents the structures, natural sources, and biological activities of the six classes of bibenzyls in detail. We also summarize bibenzyl chemical synthesis methods and propose strategies for their biosynthesis, which may facilitate the systematic development of bibenzyl compounds for further research.