Alpha-Glucosidase Inhibitory Diterpenes from Growing in Vietnam.

Bioactive-guided phytochemical investigation of L. growing in Vietnam led to the isolation of five -atisanes, one --atisane, and one lathyrane (ingol-type). The structures were elucidated as -131617-tetrahydroxyatisane (), ethyl -3,4--4,16,17-trihydroxyatisane-3-carboxylate (), -atisane-3-oxo-16,17-acetonide (), -3-acetoxy-16,17-dihydroxyatisane (), -16,17-dihydroxyatisane-3-one (), calliterpenone (), and ingol 12-acetate (). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, is a new compound while is an ethylated artifact of -3,4--4,16,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound showed the most significant inhibitory activity against alpha-glucosidase with an IC value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that could retard the enzyme function by noncompetitive.