Next Article in Journal
Bioactive Constituents from the Whole Plants of Gentianella acuta (Michx.) Hulten
Next Article in Special Issue
Different Inhibitory Potencies of Oseltamivir Carboxylate, Zanamivir, and Several Tannins on Bacterial and Viral Neuraminidases as Assessed in a Cell-Free Fluorescence-Based Enzyme Inhibition Assay
Previous Article in Journal
Fluorescent Polystyrene Films for the Detection of Volatile Organic Compounds Using the Twisted Intramolecular Charge Transfer Mechanism
Previous Article in Special Issue
Chemical Composition, Antibacterial and Antifungal Activities of Crude Dittrichia viscosa (L.) Greuter Leaf Extracts
Open AccessArticle

Characterization of Proanthocyanidin Oligomers of Ephedra sinica

Department of Natural Product Chemistry, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
Author to whom correspondence should be addressed.
Molecules 2017, 22(8), 1308;
Received: 14 July 2017 / Revised: 27 July 2017 / Accepted: 3 August 2017 / Published: 6 August 2017
Ephedra sinica, an important plant in Chinese traditional medicine, contains a complex mixture of proanthocyanidin oligomers as major constituents; however, only the minor components have been chemically characterized. In this study, oligomers with relatively large molecular weights, which form the main body of the proanthocyanidin fractions, were separated by adsorption and size-exclusion chromatography. Acid-catalyzed degradation in the presence of mercaptoethanol or phloroglucinol led to the isolation of 18 fragments, the structures of which were elucidated from their experimental and TDDFT-calculated ECD spectra. The results indicated that (−)-epigallocatechin was the main extension unit, while catechin, the A-type epigallocatechin–gallocatechin dimer, and the A-type epigallocatechin homodimer, were identified as the terminal units. Among the degradation products, thioethers of gallocatechin with 3,4-cis configurations, a B-type prodelphinidin dimer, a prodelphinidin trimer with both A- and B-type linkages, and a prodelphinidin dimer with an α-substituted A-type linkage were new compounds. In addition, a phloroglucinol adduct of an A-type prodelphinidin dimer, a doubly-linked phloroglucinol adduct of epigallocatechin, and a unique product with a flavan-3-ol skeleton generated by the rearrangement of the aromatic rings were also isolated. View Full-Text
Keywords: Ephedra sinica; proanthocyanidin; oligomer; thiolysis; phloroglucinolysis; TDDFT; ECD Ephedra sinica; proanthocyanidin; oligomer; thiolysis; phloroglucinolysis; TDDFT; ECD
Show Figures

Figure 1

MDPI and ACS Style

Orejola, J.; Matsuo, Y.; Saito, Y.; Tanaka, T. Characterization of Proanthocyanidin Oligomers of Ephedra sinica. Molecules 2017, 22, 1308.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Search more from Scilit
Back to TopTop