GC-MS analysis of metabolites from soxhlet extraction, ultrasound-assisted extraction and supercritical fluid extraction of Salacca zalacca flesh and its alpha-glucosidase inhibitory activity

Different extraction processes were employed to extract bioactive metabolites from Salacca zalacca flesh by a range of aqueous and organic solvents. The highest extraction yield was obtained by 50% ethanol extract of SE (73.18 +/- 4.35%), whereas SFE_1 showed the lowest yield (0.42 +/- 0.08%). All extracts were evaluated for in vitro alpha-glucosidase inhibitory activity, measured by their IC50 values in comparison to that of quercetin, the positive control (IC50 = 2.7 +/- 0.7 mu g/mL). The lowest alpha-glucosidase inhibitory activity was indicated by water extract of SE (IC50 = 724.3 +/- 42.9 mu g/mL) and the highest activity was demonstrated by 60% ethanol extract by UAE (IC50 = 16.2 +/- 2.4 mu g/mL). All extracts were analysed by GC-MS and identified metabolites like carbohydrates, fatty acids, organic acids, phenolic acids, sterols and alkane-based compounds etcetera that may possess the potential as alpha-glucosidase inhibitor and may attribute to the alpha-glucosidase inhibitory activity. [GRAPHICS] .