Gynostemosides A–E, megastigmane glycosides from Gynostemma pentaphyllum

Chemical Constituents of Ficus drupacea Leaves and Their α-Glucosidase Inhibitory Activities

“…C-NMR spectra of 1 were similar to those of 4'-dihydrophaseic acid 10 except for a carboxylic group replaced by carboxylate sodium group in C-1 (see Supporting information). The presence of carboxylate sodium group at C-2 in 1 was confirmed by HR-ESI-MS and by comparing Figure 3).…”

A new megastigmane diglycoside from Litsea glutinosa (Lour.) C. B. Rob.

“…Several oxidation steps and glycosylation at the megastigmane scaffold afforded several derivatives with anti-proliferative, anticancer and cytotoxic effects. 18,19,[25][26][27][28] Compound 1 was tested for its cytoxicity effects in the human tumor cell lines myeloid leukemia HL-60, hepatocellular carcinoma SMMC-7721, lung cancer A-549, breast cancer MCF-7 and colon cancer SW480 cells, but it proved to be inactive (IC 50 > 40 mM). …”

Three New Megastigmane Glucopyranosides from the Cardamine komarovii

“…The relative stereochemistry of the aglycone moiety in 1 was characterized by a nuclear Overhauser enhancement spectroscopy (NOESY) experiment, which showed NOE correlations between the following proton pairs (H-2a and H-3; H2b and H-12; H-3 and H-4; H-7 and H-12) as shown in , it is suggested that two hydroxyl groups at C-3 and C-4 are in the cis configuration. 13,14) Enzymatic hydrolysis of 1 with b-glucosidase (emulsin) yielded 3,4-dihydroxy-5,7-megastigmadien-9-one (1a, C 13 configuration at C-3 in 1a was determined by a modified version of Mosher's method. 16) Based on further comparison of the NMR data with those in the literature, the absolute configuration at C-3 in 1 was determined to be the S-form.…”

“…2 Hz), it is suggested that two hydroxyl groups at C-3 and C-4 are in the cis configuration. 13,14) Enzymatic hydrolysis of 2 with b-glucosidase (emulsin) yielded 5,6-epoxy-3,4-dihydroxy-7-megastigmen-9-one (2a, C 13 O)}. The absolute configuration at C-3 of 2a was determined to be the S-form.…”

“…In the NMR spectra of 3, the signals at d 35 (H-2a, dd, Jϭ12.8, 3.5 Hz), it is suggested that two hydroxyl groups at C-3 and C-4 are in the cis configuration. 13,14) Enzymatic hydrolysis of 3 with b-glucosidase (emulsin) yielded 5,6-epoxy-3,4,9-trihydroxy-7-megastigmen (3a, C 13 C-NMR and MS spectra were very similar to those of 5,6-epoxy-3,4,9-trihydroxy-7-megastigmen, which was isolated from Staphylea bumalda, 9) and D-glucose {[a] D 25 ϩ51°(cϭ0.05, H 2 O)}. Determination of the absolute configuration at C-3 and C-9 of 3 was done using Mosher's method.…”