Purification of novel stilbene oligomers from vine stalks by centrifugal partition chromatography guided by mass spectrometry

Stilbenes are known to be frequently encountered in a limited number of families: Cyperaceae, Dipterocarpaceae, Gnetaceae, and Vitaceae [1]. Resveratrol (E-3,5,4'-trihydroxystilbene), a naturally occurring phenolic compound, has been spotlighted as a potential chemopreventing agent for several pathologies such as cardiovascular and neurodegenerative diseases and different types of cancer [2]. Wine and grapes are the principal dietary sources of these compounds. In order to dispose important quantities of various stilbenes to test their biological activities in vitro and in vivo, a purification of oligostilbenes guided by mass spectrometry was undergone on Vitis vinifera cv merlot stalk extracts using centrifugal partition chromatography (CPC). In this study, the quaternary Arizona solvent systems (n-heptane/EtOAc/MeOH/Water) [3] were successfully used for the isolation of an hexamer and three trimers of resveratrol from stalks of Vitis vinifera, along with a multitude of other stilbenic compounds.

To our knowledge, this is just the fourth stilbene hexamer identified until now in the whole plant reign, a novel compound and the first stilbene hexamer ever identified in the vine. The trimers are miyabenol-C and two of its isomers, reported for the first time in the vine. Attention should also be paid to the innovative approach to their purification. The hexamer and the mixture of the three trimers were purified by CPC avoiding purification techniques using solid supports, eliminating in this way absorption on the solid support and recovering a greater amount of these compounds in a much quicker way.

References: 1. Hart, J.H. (1981) Annu. Rev. Phytopathol. 19: 437–458

2. Saiko, P. et al. (2008) Mutation Research 658: 68–94

3. Foucault, A.P., Chevolot, L. (1998)J. Chromatogr. A 808: 3–22