Methanol extracts of the rhizomes or fruit of Amomum celsum Lamxay & M.F. Newman (Zingiberaceae) yielded 5 compounds one of which, 1,3 S,5 S-trihydroxy-1-(4-hydroxyphenylethyl)cyclohexane (2), is new and one, 4-hydroxybibenzyl (1), is reported as a natural product for the first time. In addition, 3 known compounds, 5-hydroxy-3,7,3′,4′-tetramethoxyflavone (3), 3,5-diacetoxy-1,7- bis(3,4-dihydroxyphenyl)heptane (4), and 1,4-hydroquinone (5), were also isolated. Their structures were determined by performing extensive analysis of high-resolution electrospray ionization-mass spectrometry and nuclear magnetic resonance spectroscopic data. The absolute configuration of 2 was unambiguously established by X-ray crystallography and Mosher’s method. Cytotoxicity of compounds 1 and 2 against MCF-7 and Hep-G2 human cancer cell lines were tested in the sulforhodamine B cytotoxic assay. A plausible biosynthesis of 1 and 2 in A. celsum was proposed.
In our study of antidiabetic compounds from the leaves of Eupatorium triplinerve Vahl. (Asteraceae), ten compounds were isolated from the methanol leaf extract. They were determined to be β-sitosterol (1), stigmasterol (2), β-sitosterol 3-O-β-D-glucopyranoside (3), ayapanin (4), ayapin (5), thymoquinol 5-O-β-D-glucopyranoside (6), thyrsifloside (8), (E)-4-methoxymelilotoside (9), and kaempferol 3,7-di-O-β-D-glucopyranoside (10) by using ESI-MS, 1D (1H-, 13C-, DEPT) and 2D NMR (HSQC, HMBC, and NOESY) techniques. This is the first report of water-soluble compounds from E. triplinerve and compounds 6–10 were isolated for the first time from E. triplinerve. NMR profiling and HPLC analysis are fast and reliable methods to screen phytochemicals in plant samples. Due to their high concentrations in the leaf extracts of E. triplinerve, coumarins 4 and 5 could be fast screened by NMR profiling and RP-HPLC-PDA analysis. In the in vitro test for α-glucosidase inhibition of compounds 4–9, compounds 4, 5, and 7 showed the enzymatic inhibition of 40%, 46%, and 81%, respectively, at 256 μg/mL. An IC50 value of 58.65 ± 1.20 μg/mL (302 μM) was calculated for compound 7 which is lower than that of the positive control acarbose (IC50 197.33 ± 2.51 μg/mL; 306 μM).
Synthetic oleananes and seco-oleananes form a group of promising anti-inflammatory and cancer chemopreventive agents with an excellent safety profile. These compounds are usually prepared by semi-synthesis from natural oleanane triterpenoids. Since a taraxer-14-ene was reported to be rearranged into an olean-12-ene under mild reaction conditions, a rapid synthesis of seco-oleananes from taraxerone, which is a readily available starting material, was explored by us. Treatment of taraxerone with m-chloroperoxybenzoic acid gave 14,15-epoxy lactones, which underwent the taraxerane-oleanane rearrangement leading to new seco-oleanane triterpenoids.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.