Chemical Constituents From the Aerial Part of Tiliacora triandra (Colebr.) Diels and Their α-Glucosidase and α-Amylase Inhibitory Activity

Two new fatty acid derivatives identified as 5,7-dihydroxy-6-oxoheptadecanoic acid (1) and ethyl-5,7-dihydroxy-6-oxooctadecanoate (2) together with four known compounds, ethyl linolenate (3), ethyl linoleate (4), ethyl pheophorbide A (5), and pheophorbide A (6), were isolated from the aerial parts of Tiliacora triandra. All the compounds were isolated from T. triandra for the first time. The structures of the compounds were elucidated using high-resolution electrospray ionization mass spectrometry, 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopy, and comparison with literature data. All the isolated compounds were evaluated for their in vitro inhibitory activity against α-glucosidase and α-amylase. Compounds 1-6 exhibited α-glucosidase inhibitory activity with half-maximal inhibitory concentration values (IC50) values in the range of 11.58-424.06 μM, while only compound 1 displayed inhibitory activity against α-amylase at an IC50 value of 26.27 μM.