Phenolic constituents from the root bark of Morus alba with emphasis on morusin and its anti-cancer properties

Abstract

The root bark of Morus alba L. or white mulberry is widely used as traditional medicine in China, Japan and Korea. Major classes and types of phenolic compounds isolated from the root bark are flavonoids(kuwanons, morusin, cyclomorusin and sanggenons), benzofurans(moracins and mulberrofurans), and stilbenoids(mulberrosides). Some of the flavonoids and benzofurans are products of Diel-Alder type adducts. Other classes of compounds include triterpenes, phenolic acids and coumarins. Morusin, a prenylated flavonoid, was first isolated from the root bark of M. alba, and later from the leaf, stem bark and twig of the plant. The potent anti-cancer properties of morusin have attracted much attention with research on-going and new findings being published. The compound inhibits angiogenesis, tumour progression and tumour migration, and triggers apoptosis, cell cycle arrest and autophagy in colorectal, cervical, prostate, breast, hepatoma, pancreatic, glioblastoma, gastric, ovarian and lung cancer cell lines. The anti-cancer activities of morusin are executed via various molecular targets and signalling pathways. It is anticipated that on-going in vitro studies will progress gradually to in vivo studies using animal models before efforts towards drug development can be initiated for clinical trials.