• Mass Spectrometry Letters
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• v.6 no.4
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• pp.99-104
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• 2015

A liquid chromatography mass spectrometry (LC-MS) system was used to identify and distinguish oligostilbene diastereoisomers. A polyphenolic extract from Neobalanocarpus heimii known to be rich in oligostilbenes of various degrees of condensation was used as test material. Fourteen oligostilbenes were isolated from this extract on a fully automated semi-preparative HPLC system. Out of these, two pairs of dimers, one pair of trimers, two pairs of tetramers and a group of four tetramers with similar skeleton were identified as diastereoisomers. Their structures and configurations were established by spectroscopic methods. All isolated compounds were subjected to an LC-MS/MS to study their fragmentation patterns. The experiments were performed on a liquid chromatography-mass spectrometry (LC-MS) with electrospray-ionization (ESI) interface in positive mode. MS/MS spectra of each pure compound were recorded by direct infusion in identical conditions and their product ion spectra were analysed. Some subtle yet significant differences were observed between the spectra of oligostilbenes from the various diastereoisomeric series.

• Natural Product Sciences
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• v.16 no.4
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• pp.223-227
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• 2010

The DNA Topoisomerase I (DNA Topo I) inhibitory effect of ten isolated compounds (1.10) from the leaf and stem of Vitis amurensis were examined. Among them, amurensin G (5) and r-2-viniferin (7) showed high potent inhibitory activity against DNA Topo I. DNA Topo I, an important target for anticancer drugs, can cause DNA breaks and play a key role during cell proliferation, transcription and repair. Thus, the results suggest that the selected compounds (5 and 7) from Vitis amurensis have a possibility as DNA Topo I-targeting anticancer agents.

• Natural Product Sciences
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• v.17 no.2
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• pp.65-79
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• 2011

Reactive oxygen species potentially cause damage to cellular components including lipids, protein and DNA; this oxidative damage plays a key role in the pathogenesis of neurodegenerative disease, cardiovascular disease, metabolic disease and cancer. On the basis of the oxidative stress hypothesis, a number of studies have been performed to search for an efficient and safe antioxidant. Although in vitro studies have provided promising results, only a limited number of natural and synthetic antioxidants have been developed for clinical application due to their low efficacy and side-effects. Thus, the discovery of new antioxidants with marked efficacy and safety has attracted worldwide attention in recent decades. Since plants are recognized as important sources of natural antioxidants, our research has focused on the discovery of new naturally occurring antioxidants from medicinal plants. The purpose of this review is to open a new prospect in the field of search for natural antioxidants from medicinal plants by summarizing our recent findings. Using in vitro bioassay systems such as 2,2-diphenyl-1-picrylhydrazyl, superoxide radical scavenging tests and lipid peroxidation models, we have tested over than 350 species of medicinal plants for their antioxidant activity and selected several of them for further investigation. During the research on the discovery of effective natural antioxidants from the medicinal plants selected, we have isolated several new and known antioxidant compounds that include stilbene glycosides, phenolic glycosides, flavonoids, oligostilbenes, and coumarins. Our results suggest that the presence of antioxidant compounds in the medicinal plants might be associated with the traditional use to treat inflammation, cardiovascular disease and various chronic diseases.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.105-111
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• 2015

Sixteen compounds of Neobalanocarpus heimii were successfully identified directly from their plant extract using a triple quadrupole LC-MS/MS system. In order to fulfil the objectives of this work, a series of stilbene oligomers of various degrees of condensation were isolated and their structure are characterized. Out of these, four are resveratrol dimers, three trimers, and nine tetramers. The isolation process was done on a fully automated semi-preparative HPLC system. Their structures were elucidated on the basis of 1D- and 2D-NMR as well as MS data. The mass fragmentation patterns of the compounds were recorded and a retrievable in-house library was built to keep the data. In order to demonstrate the potential of this approach, the polyphenolic crude extract was analysed with the LC-MS/MS system and the MS/MS spectra extracted for each chromatographic peak of interest. The fragmentation patterns were compared with those of anticipated pure compounds that were previously recorded. All compounds were successfully identified. It is therefore believed that the LC-MS/MS potential for dereplication of structurally similar compounds in a crude mixture was thus firmly established.