Cytotoxicity studies of a stilbene extract and its main components intended to be used as preservative in the wine industry.

The use of stilbenes has been proposed as an alternative to sulfur dioxide in wine. Provided the feasibility from a technological approach, the cytotoxicity of an extract from grapevine shoots containing a stilbene richness of 99% (ST-99 extract) was assessed in the human cell lines HepG2 and Caco-2. In addition, the effects of the main stilbenes found in ST-99, trans-resveratrol and trans-ε-viniferin were studied, as well as its mixture. Similar cytotoxic effects were obtained in the exposures to trans-ε-viniferin, ST-99 and the mixture; however, trans-resveratrol alone exerted less toxicity. When HepG2 cells were exposed to trans-ε-viniferin, ST-99 and the mixture, the mean effective concentration (EC50) were 28.28 ± 2.15, 31.91 ± 1.55 and 29.47 ± 3.54 µg/mL, respectively. However, in the exposure to trans-resveratrol, the EC50 was higher 50 µg/mL. The morphological study evidenced damage at ultrastructural level in HepG2 cells, highlighting the inhibition of cell proliferation and the induction of apoptosis. The type of interaction produced by trans-ε-viniferin and trans-resveratrol mixtures was assessed by an isobologram analysis using the CalcuSyn software, evidencing an antagonist effect. These data comprise a starting point in the toxicological assessment; further studies are needed in this field to assure the safety of the extract ST-99.