Kuwanons from Mulberry (Morus spp.): Exploring their structural activity relationship, biosynthesis, and biological properties.

The kuwanons are a class of natural isoprenylated flavonoids found in a wide array of Morus (mulberry) species, predominantly in the roots and stems of the mulberry plant. Kuwanons are the most ubiquitous compounds present in mulberry plants, and they have been the subject of much research in recent decades because of their possible medical benefits and their ability to serve multiple functions. Kuwanons are biosynthesised through integrated phenylpropanoid and polyketide pathways, followed by extensive enzymatic diversification. Based on differences in prenylation patterns, cyclisation, and oxidative modifications, kuwanons are categorised into defined structural subclasses. Kuwanons are also known for their capability to exhibit a wide spectrum of biological activities, including antiviral, antibacterial, antioxidant, tyrosinase inhibitory, anti-diabetic, anti-inflammatory, anti-hyperlipidemic, anti-asthmatic, and anti-parasitic activities. According to investigations, kuwanon-associated actions are primarily in the micromolar potency range, indicating structure-dependent bioactivity. Therefore, the current review discusses current developments in the structural diversity, biosynthesis, and biological activities of several kuwanon types along with structural activity-relationship, as well as limits and goals for future mechanistic and translational studies.