ANTIMICROBIAL ACTIVITY, ISOLATION AND ELUCIDATION OF THE THREE NEW BIOACTIVE MOLECULES WERE DERIVED OF ISOBENZOFURO[4,5C]XANTHONE, FROM THE AERIAL PARTS OF CYMBOPOGON GIGANTEUS CHIOV VAR. MADAGASCARIENSIS (POACEAE)

In Madagascar, traditional medicine holds an important place in Malagasysociety, thanks to its customs and rich biodiversity, particularly the endemicity ofplants and their therapeutic virtues. Based on ethnobotanical data, a plant knownby the vernacular name Verompoly (Sakalava name) and scientifically calledCymbopogon giganteus Chiov var. madagascariensis (Poaceae) is used by thelocal population to treat fever, infections and blood pressure problems. Theresults of biological screening tests show that the dichloromethane extract hasvery interesting antimicrobial activity. The aim of this study is to isolate theprinciples responsible for this plant's antibacterial activities. The application ofbioguided fractionation methods, using the chromatography technique ondichloromethane extract followed by antimicrobial tests to locate products,enabled us to isolate three pure active ingredients noted ( CG-01, CG-02 andCG-03). The chemical structures of these three products have been elucidatedusing mass spectrometry and nuclear magnetic resonance spectroscopy (1D and2D NMR). They are all attributed to Isobenzofuro-[4,5c]-Xanthone derivatives.The overall results of studies on this plant show that the empirical uses ofVerompoly have been scientifically proven, and their active principles areattributed to new molecules included in the family of complexes phenoliccompounds derived from Isobenzofuro-[4,5c]-Xanthone.