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Abstracts. PHYTOPHARM 2017
glucopyranoside], 5-hydroxyl-7,4'-dimethoxyflavone-6-C-[O-(a -L-3-acetylrhamnopyranosyl)-1 ^2-p -D-glucopyranoside], and 5-hydroxyl-7,4'-dimethoxyflavone-6-C-[O-(a-L-2,3-diacetylrhamnopyranosyl)-1^2-p-D-glucopyranoside]2 have been isolated and described in literature [2, 3].
As a result of phytochemical analysis of Iris lactea three new C-glycoside flavonoid compounds were isolated from Iris lactea. All of the isolated compounds shared similar UV absorption and NMR spectra. Their hydrolysis afforded a-L-rhamnose and embigenin, suggesting them to be derivatives of embinin. Further analysis using HRESIMS, COSY, HMBC and HSQC showed the three compounds to be 5-hydroxyl-7,4'-dimethoxyflavone-6-C-[O-(a-L-2,4-diacetylrhamnopyranosyl)-1^2-p-D-glucopyranoside], 5-hydroxyl-7,4'-dimethoxyflavone-6-C-[O-(a -L-4-acetylrhamnopyranosyl)-1 ^2-p -D-glucopyranoside] and 5-hydroxyl-7,4'-dimethoxyflavone-6-C-[O-(a-L-4-acetylrhamnopyranosyl)-1 ^2-p -D-6-acetylglucopyranoside].
O-glycosyl flavones are known as one of the major components in genus Iris, which were mainly isolated from leaves and flowers. There are few reports about C-glycosyl flavonoids from this genus. C-glycosylflavonoids are found to be minor constituent in the extract and their roles in plant physiology needs further research. Inspection of their NMR data revealed the duplication of the signals, indicating the presence of rotamers. This is caused by the rotational hindrance at the C(6)-C(1') linkage, which cannot be found in mono-6-C-substituted derivatives.
References:
1. Reynaud J, Guilet D, Terreux R, Lussignol M, Walch-shofer NI. 2005. Nat. Prod. Rep. 22/504-515.
2. Pryakhina NI, Sheichenko VI, Blinova KF. 1984. Chem. Nat. Compd. 20:554-559.
3. Shen WJ, Qin MJ, ShuP, Zhang CF. 2008. Chin. Chem. Lett. 19:821-824.
HOW FAR DEEP CAN PLANT METABOLITE PROFILING CAN BE PERFORMED? IMPLICATIONS FOR DRUG DISCOVERY AND QUALITY CONTROL OF HERBALS
© Jean-Luc Wolfender, Pierre Marie Allard, Emerson Ferreira Queiroz
School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
With the recent progresses made in metabolite profiling methods and miniaturization of bioassays, a question that arises is: do we still need to perform conventional large scale bioactive guided-isolation of natural products to characterise the extract composition of an herbal drug and identify its active ingredients?
High resolution mass spectrometry (HRMS) and data dependent MS/MS analyses provide very valuable information on secondary metabolites for in-depth metabolome annotation studies [1]. The recent development of molecular network (MN) approaches for the mining of such data in combination with spectral database generated in silico [2] gives the possibility to establish relationships between metabolites thus significantly improving the efficiency of dereplication when combined with high quality chemotaxonomic data [3]. Such types of information can be generated with a few mg of extract only and are readily applicable to herbarium scale samples.
For complete de novo identification of new compounds MS-targeted micro-isolation can be performed and sensitive 1D and 2D microNMR with microgram amounts of purified metabolites can be acquired. For bioactivity determination, many bioassay fit also to this scale. Using an ideal combination of methods it is this virtually possible to fully identify any bioactive principles in this way. Integration of other filters to this approach such as permeation studies on extracts additionally provide key
information on the possible bioavailability of NPs prior to their isolation. Furthermore the link of a given bioactivity result to those previously reported for compounds similar to those identified can be rationalised through in silico chemical space approaches.
Ideally a combination all these state-of-the-art methods should enable to identify and localise valuable NP efficiently at the analytical scale. In such a way large scale MS-targeted isolation of valuable NPs only can become a very rational way to conduct investigations. Different recent applications of our metabolomics and phytochemical investigations will illustrated these aspects.
Such strategies have different implications for drug discovery but also for quality control of herbal and such issues will be discussed. A summary of what could be an ideal workflow will be presented and discussion on what is readily implemented and what is still required will be made.
References:
1. Wolfender JL, Marti G, Thomas A, Bertrand S. 2015. J Chromatogr A. 1382:136-164.
2. Allard PM, Peresse T, Bisson J, Gindro K, Marcourt L, Pham VC, Roussi F, Litaudon M, Wolfender JL. 2016. Anal. Chem. 88:3317-3323.
3. Wolfender JL, Genta-Jouve G, Allard PM. 2017. Curr. Opin. Chem. Biol. 1 (in press).
Obzory po kliniceskoj farmacologii i lekarstvennoj terapii [Reviews of clinical pharmacology and drug therapy]
vol. 15/2017/suppLement 1
