bioactive biflavonoids from wikstroemia indica (l.) c.a. mey. (thymelaeaceae): a review

The roots of the plant wikstroemia indica (l.) c.a. mey., also known as radix wikstroemiae or liaogewanggen in china, are used in traditional medicine as decoctions for the treatment of diverse inflammatory diseases, such as arthritis, bronchitis, and many other conditions. a large diversity of bioactive natural products have been characterized in w. indica including flavonoids, lignans, coumarins and sesquiterpenes. a scoping review was designed to identify the variety of biflavonoids isolated to date from the plant (mostly but not exclusively from the roots) and to depict their mode of action, based on database retrieval and a detailed analysis of all the relevant scientific literature. a focus has been made on two important series of c-3 linked dimeric compounds, sikokianins and wikstroflavones, and their anticancer properties and mechanism of action. sikokianins a-d are atypical c-3/c-3’’ biflavonoids, with sikokianin c as a lead molecule acting as an inhibitor of cystathionine β-synthase (cbs) and exhibiting marked anticancer properties in vivo. wikstroflavones a-b and wikstaiwanones a-b are unusual flavone/ flavanol dimers with a c-3/c-6'' linkage. wikstroflavone b can potentiate the antiproliferative and antimetastatic activity of anticancer products. a few other biflavonoids have been isolated from the rhizomes of w. indica, such as daphnodorin derivatives. a biflavonoid-oriented survey of wikstroemia indica is provided to highlight the potential benefit of the roots of wikstroemia indica for the treatment of cancer.