Tannase‐treated grape pomace attenuates IL‐1β‐induced inflammation in Caco‐2 cells

Grape pomace (GP) derived from wine production is rich in glycosidic phenolics which may possess a lower bioefficacy than their respective aglycones. Thus, we examined whether GP treated with Paecilomyces variotii tannin acyl hydrolase (tannase) to hydrolyze the ester and the depside bonds between conjugates and phenolics enhances anti‐inflammatory actions in vitro . GP was treated with tannase at 40 °C and pH 5.5 for 5 h. Phenolics in GP and tannase treated GP (GPT) were extracted with 70% methanol in acetate buffer, dried under N 2 air, and reconstituted in PBS for tests. GPT contained 45% more quercetin and 71% less quercetin‐3‐O‐rutinoside than GP. Further, GPT had 39% more total phenols than GP and displayed 57, 215, and 12% greater total antioxidant capacity per DPPH, ORAC, and FRAP analyses, respectively. However, GP and GPT at 100 and 200 μg/mL (dry extract wt/v) displayed comparable efficacy in the reduction of ROS production in Caco‐2 cells treated with or without 50 μM AAPH. After 24‐h pretreatment, GPT at 200 μg/mL decreased 20 ng/mL IL‐1β‐induced PGE 2 production by 110% and IL‐8 by 83% and down‐regulated NF‐κB activation by 68% relative to controls. GPT was more potent than GP in the amelioration of IL‐1β‐induced inflammation. Therefore, tannase treatment appears to enhance the antioxidant and anti‐inflammatory activities of grape pomace phenolics and suggests the potential application of this material in food and beverage products. Support or Funding Information Supported by USDA