Characterization of 2,5-dimethyl-2,4-dihydroxy-3(2H) furanone, A Flavourant Principle From Sysepalum dulcificum

Abstract

In this study, three solvent extracts (ethanol, acetone and hexane) were obtained from Synepalum dulcificum ((Daniell) known locally as " ntum " in Akaeze dialect of Igbo language of Nigeria and traditionally used as sweetener were evaluated for its flavourant principles. The presence of bioactive components were detected and the result of the cold solvent extraction revealed that ethanol gave the highest percent extract recoveries of 1.816%, hexane gave 0.873% while the lowest yield was observed for acetone as 0.508%. Quantitative assay revealed that ethanolic extracts had the highest content of flavonoids, glycosides, phenols, tannins, saponins and alkaloids (6.10%, 3.20%, 2.8%, 2.00%, 1.3% and 0.14%) respectively. This was followed by the acetone extracts which gave the values for flavonoids (0.70%), glycosides (0.50%), saponins (2.12%), phenols (1.60%), tannins (0.26%) and alkaloids (0.62%). The TLC plate developed and sprayed with vanillin/sulphuric acid reagent (EMW) exhibited three main bands of distinct colours in the acetone (ACE) extract while ethanol (ETE) yielded six bands. The flavour threshold was determined at neutral and slightly acidic pH 4.5. The results showed that extracts of ACE and ETE revealed strong presence of the active principles up to 0.1% at pH 7.0 and 0.01% at a pH of 4.5. Chromatographic analysis of acetone extract revealed that component A-3 has a melting point of 65-67°C while the GC analysis of A-3 showed the eluate of two compounds at different retention times of 12.692 and 15.125 minutes. Spectral Analysis of compounds in A-3(a,b) revealed that they are possible isomers and based on spectral data the structure of compound A-3a was proposed as 2, 5-dimethyl-2, 4-dihydroxy-3(2H)-furanone.