Chemical composition and in vitro α-amylase inhibitory activity of Meistera vespertilio (Gagnep.) Skornick. & M.F. Newman essential oils collected in two different regions of Vietnam

Meistera, belongs to the Zingiberaceae family, is a genus of medicinal plants that contain a rich resource of essential oils (EOs) as well as have many valuable bioactivities. The aim of the present study was to investigate the EOs of Meistera vespertilio, which has not been reported before. The EOs were distilled by hydrodistillation method from M. vespertilio rhizomes collected in two different regions (Phu Tho and Nghe An Provinces) of Vietnam. The compositional analysis of two EO samples was carried out using Gas Chromatography-Mass Spectroscopy (GC-MS). GC-MS analysis showed that the two samples had a different number of chemical components. The Phu Tho EO sample consisted of more components (51 compounds) compared to the Nghe An EO sample (41 compounds). However, the two EOs were identified with some similar components including α-pinene, camphene, β-pinene, and limonene. Furthermore, both EO samples possessed good inhibitory effects on α-amylase, with average IC50 values ranging from 0.61 to 0.91 (mg/mL). Especially, the EO of M. vespertilio rhizomes from Nghe An Province showed intense α-amylase inhibitory activity (IC50 value of 0.61 ± 0.00 mg/mL) which was stronger than acarbose, an antidiabetic drug (IC50 value of 0.92 ± 0.01 mg/mL), while the figure for Phu Tho EO showed approximately equivalent activity. The results obtained in the present study showed the potential of M. vespertilio EOs as a valuable source of chemical compounds for the food and pharmaceutical industry.