Chemical composition and enzymatic inhibitory activities related to diabetes of Hedychium malayanum rhizome and leaf essential oils essential oils

In this study, the composition of essential oils (EOs) from H. malayanum rhizomes and leaves, collected from Bidoup-Núi Bà National Park in Southern Vietnam, and their α-amylase and α-glucosidase activity are demonstrated. Gas chromatography-mass spectrometry (GC-MS) analysis identified 34 compounds (99.54%) in rhizome EO (RHM-EO) and 40 compounds (99.13%) in leaf EO (LHM-EO). The major components of rhizome EO included 1,8-cineole (39.33±0.34), β-pinene (23.36±0.13), α-pinene (9.65±0.03), and α-limonene (5.57±0.06), while the leaf EO was rich in β-pinene (57.8±0.25), α-pinene (14.93±0.13), and β-(E)-caryophyllene (9.43±0.17). Both oils exhibited α-amylase inhibitory activity, with IC50 values of 499.10± 6.20 μg/mL (LHM-EO) and 609.04 ± 14.72 μg/mL (RHM-EO), respectively, which were lower than the reference compound, acarbose (IC50 = 271.51±13.51 μg/mL). Unfortunately, both H. malayanum EOs were found to be inactive against α-glucosidase under the tested experimental conditions. To our best knowledge, this is the first report on the composition of rhizome EO and bioactivities of H. malayanum from Vietnam.