Characterization of Anti-Inflammatory and Anti-Proliferative Triterpenoids and Phytosterols from Cranberry Pomace

Abstract

Vaccinium macrocarpon (American Cranberry) fruit is processed to make juice, supplements, and other edible products, leaving pomace as a sidestream that contains secondary metabolites with potential anti-inflammatory and anti-proliferative activities. Ultrasound-assisted extraction and chromatographic methods were developed to prepare an extract (POM-ACE) and fractions rich in pentacyclic triterpenoids and phytosterols for bioactivity evaluation. These were characterized using UPLC-MS and GC-MS. Anti-inflammatory effects were assessed in a human monocyte (THP-1) model, identifying several fractions containing triterpenoids and sitosterol that significantly inhibited IL-1β expression. Molecular docking indicated favorable interactions of these components with NLRP3, suggesting a possible modulation of inflammasome. Fractions rich in ursolic acid (UA) and oleanolic acid (OA) and their p-hydroxycinnamic acid (HCA) esters also showed mild concentration-dependent inhibition of lipoxygenase (LOX) activity. Pearson correlation analysis identified strong positive correlations between UA, OA, and their trans-HCA esters with LOX inhibition. Anti-proliferative activity was assessed in HT-29 colon adenocarcinoma cells using MTT, with several fractions exhibiting moderate concentration-dependent activity (IC50 = 12–17 µg/mL). PLS regression analysis supported significant contributions by UA, OA, and their HCA esters. Flow cytometry experiments demonstrated that cell death occurs in part through apoptosis; the role of apoptosis was further supported by favorable molecular docking interactions between pomace triterpenoids and caspases-3 and -9. These findings suggest that cranberry pomace is a promising source of triterpenoids and phytosterols with anti-inflammatory and anti-proliferative properties.