Alpha-Glucosidase Inhibitory Diterpenes from Euphorbia antiquorum Growing in Vietnam

Abstract

Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16β,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16β,17-acetonide (3), ent-3α-acetoxy-16β,17-dihydroxyatisane (4), ent-16β,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). 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, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive.

Alpha-glucosidase inhibitors from Nervilia concolor, Tecoma stans, and Bouea macrophylla

“…The mechanism of alpha-glucosidase inhibition by BM3 was determined using Lineweaver-Burk plots (Microsoft Excel 2010, Washington, USA), following methods reported in the literature ( Tran et al, 2021 ). Enzyme inhibition at the different BM3 concentrations was evaluated from the substrate.…”

Flavones from Combretum quadrangulare Growing in Vietnam and Their Alpha-Glucosidase Inhibitory Activity

“…The enzymatic reaction was carried out at 37 • C for 20 min and stopped by adding 0. The mechanisms of inhibition of alpha-glucosidase by 8 and 11 were determined by Lineweaver-Burk plots (Microsoft Excel 2010, Washington, WA, USA), using methods similar to those reported in the literature [28]. Enzyme inhibition due to various concentrations of the 8 and 11 compounds were evaluated by monitoring the effects of different concentrations of the substrate.…”

New Molecules of Diterpene Origin with Inhibitory Properties toward α-Glucosidase

“…The literature data regarding the mechanism of α-glucosidase inhibition for diterpenes is scarce. The majority of reported compounds are non-competitive inhibitors, e.g., ent-atisane-3-oxo-16β,17-acetonide [ 39 ], (E)-labda-8(17),12-diene-15,16-dial [ 40 ], ent-kaurane derivative of chepraecoxin A [ 41 ], and bis-labdanic diterpene were reported as mixed-type inhibitors [ 42 ]. Notably, these inhibitors share an alicyclic core.…”