Ohmic heating polyphenolic extracts from vine pruning residue with enhanced biological activity

Abstract

Vine Pruning residue was submitted to conventional heating and ohmic heating (OH) for the extraction of bioactive compounds and analyzed for total phenolic content (TPC), polyphenolic profile, antioxidant activity, antimicrobial activity and anticancer activity. The OH extracts were obtained using Low electric field (496.0 V/ cm) or Intermediate electric field -IEF (840.0 V/cm). The tests were performed using 45% (v/v) ethanol-water extraction solution at 80°C at different extraction times (20-90 min). The extract that stood out among the others concerning anticancer potential was the one obtained by OH when used, IEF, where the TPC was significantly higher than in the other extracts which correlated with higher antioxidant, antimicrobial and antiproliferative activity on different tumor cell lines (HepG2, MDA-MB-231, MCF-7 and Caco2). Vine pruning OH extracts obtained using green solvents by an eco-friendly procedure were revealed as a source of compounds with relevant antioxidant and anticancer activity.

Ohmic Heating Extract of Vine Pruning Residue Has Anti-Colorectal Cancer Activity and Increases Sensitivity to the Chemotherapeutic Drug 5-FU

“…Resveratrol and quercetin (and several of its derivatives) have been found in many grapevine by-products, together with other compounds [5]. Among the bioactivities attributed to these compounds are antioxidant, antimicrobial and anticancer activity [16][17][18]. Although positive health effects of other wine industry residues have been shown, and pharmaceutical drugs patented and marketed [19], vine pruning extracts have not been explored for this purpose.…”

“…The extraction parameters defined in this study were based on previous results [16,20]. Briefly, the extractions were carried out in a glass cylindrical reactor of 30 cm total length and 2.3 cm of internal diameter, containing two stainless steel electrodes insulated with polytetrafluoroethylene, kept at a constant distance of 7 cm.…”

“…Vine pruning residues constitute valuable biomass that can be used in a biorefinery scheme, considering their high content in antioxidant compounds (phenolic compounds derived from lignin processing) [11][12][13], and as a potential source of xyloligosaccharide prebiotics [14]. They can also be used as biofuels through the hydrolysis and fermentation of cellulose to ethanol [15] or as a source of bioactive polyphenols [16].…”

“…Recently, we have reported on ohmic heating, an environmental friendly polyphenol extraction technique, that allowed an increase in phenolic compound extraction from vine pruning residue, relative to extraction at room temperature [16]. In addition to quercetin, which was present in both extracts, hesperidin, ellagic acid and apigenin accounted for the majority of phenolics extracted by ohmic heating (Table 1).…”

“…Major phenolic constituents of vine pruning residue extracts obtained by two different extraction methods: at room temperature (RT) and by ohmic heating (vine pruning residue (VPE)). For more details see [16]. (*) Includes all compounds identified [16].…”