Isolation and structural elucidation of flavonol and a flavonol glycoside from the butanol fraction of Globimetula oreophila a mistletoe on Azadirachta indica A. Juss (melliacea)

Introduction: Globimetula oreophila belongs to the family Loranthaceae, and it is a hemiparasitic shrub that grows on dicotyledonous trees like neem trees, rubber trees, citrus trees, cocoa trees, and kola nuts. In traditional medicine, it is used to treat conditions like malaria, diarrhea, headaches, and insomnia. The G. oreophila genus and family (Loranthaceae) are poorly studied regarding their secondary metabolite constituents. This research study aims to isolate and characterize some of the bioactive secondary metabolites present in the butanol fraction of G. oreophila. Method: the powdered plant material was extracted with 70% ethanol using cold maceration which afforded the crude ethanol extract. Partitioning of the crude ethanol extract with n-hexane, chloroform, ethyl acetate, and n-butanol produced the corresponding fractions, where the n-butanol fraction was subjected to silica gel column chromatography and repeated gel filtration. Results: column chromatographic separation of the n-butanol fraction led to the isolation of a yellowish amorphous substance as flavonol (1) and flavonol glycoside (2). Physical and chemical tests, spectroscopic analysis, and literature data led to the elucidation of compounds 1 and 2 as quercetin (5, 7, 3’, 4’-tetrahydroxy-quercetin-3-O-α-L-rhamnopyranoside) and quercetin rhamnoside (3, 5, 7, 3’, 4’-pentahydroxy flavone), respectively. Conclusion: Compounds 1 and 2 were isolated for the first time from the plant and contributed to the chemical taxonomy of the plant.