Isolation and Characterisation of an Isolated Flavonoid from Averrhoa bilimbi

Averrhoa bilimbi is a tropical plant which is commonly known as Bilimbi. The plant has enormous economic importance since its leaves, flower, fruit, bark, seeds, roots or the whole plant are used to treat a variety of diseases in the alternative system of medicine. In the present work, attempt was made to isolate a flavonoid compound from Averrhoa bilimbi. From the methanolic extract of the fruits of Averrhoa bilimbi, a pentahydroxyl flavanonol has been isolated as a major compound for the first time in this plant. The isolate was purified, analysed and characterised by using UV, FTIR, Mass, NMR, HPTLC and HPLC. The Rf value for HPTLC was found to be 0.24, λ max of UV spectra was obtained at 277 nm and retention time in HPLC was 2.55. The structure of this isolated compound has been characterised as dihydromyricetin i.e ‘(2R,3R)-3,5,7-trihydroxy-2-(3,4,5-trihydroxyphenyl)-2,3-dihydrochromen-4-one’ with molecular formula C15H12O8 and molecular mass 320.0529. The structure is established on the basis of 1D and 2D Nuclear Magnetic Resonance (NMR) and also High Resolution Mass Spectral i.e HRMS data.