A new bioassay-guided fractionation from root of Bryonia dioica: A promising strategy for drug discovery

Abstract

The discovery of bioactive natural compounds is largely related to the development and the sensitivity of biological methods. In our search for new antitumor and anti-inflammatory molecules, we have developed a new strategy to identify active compound from the roots of bryonia dioica (cucurbitaceae), which are widely used in traditional medicine to treat chronic diseases such as arthritis and rheumatism. Tumor necrosis factor alpha (TNF-α) is a central cytokine that drives the inflammation; hence inhibition of TNF-α offers an attractive treatment strategy. We used the human TNF promoter as biotool to identify active molecules. Crude extract was separated on an appropriate column chromatography and obtained fractions were tested to select the active fractions. Bryonia crude extract was found to exhibit a strong inhibitory effect on the proliferation of human U2OS osteosarcoma cells. By bioassay-guided fractionation, we isolated active fractions with a strong inhibitory action on the transcriptional activity of TNF promoter. Further fractionation was carried out: in purified active sub-fraction, we isolated and confirmed the structure of cucurbitacin E by NMR and HRMS as an active molecule. These results are very promising since they show that our bioassay-guided fractionation methodology could be applied for the detection of active compounds.