Beneficial Effects of White Grape Pomace in Experimental Dexamethasone-Induced Hypertension.

Abstract

Background: Grape pomace (GP), a by-product of winemaking, is a rich source of bioactive polyphenols known for their antioxidant and anti-inflammatory properties. While the cardiovascular benefits of red grape pomace have received significant scientific attention, the therapeutic potential of white grape pomace remains largely unexplored, particularly in glucocorticoid-induced hypertension. Given the rising prevalence of hypertension and the oxidative-inflammatory mechanisms underlying its progression, this study investigates the effects of white GP on blood pressure regulation, oxidative stress, and pro-inflammatory cytokine expression in an experimental model of dexamethasone (DEXA)-induced hypertension (HTN). By focusing on white GP, this research addresses a significant gap in current knowledge and proposes a novel, sustainable approach to managing hypertension through valorising winemaking by-products.

Methods: The first concentration used, GP1, was 795 mg polyphenols/kg bw, while the second concentration, GP2, was 397.5 mg polyphenols/kg bw.

Results: White GP polyphenols extract in the DEXA_GP1 group had reduced systolic and diastolic blood pressure. The extract with a higher content of polyphenols (GP1) prevented the elevation of serum levels of total oxidative stress (TOS), malondialdehyde (MDA), and oxidative stress index (OSI), while the extract with a lower content of polyphenols (GP2) slightly reduced serum levels of MDA. Both concentrations of GP increased serum levels of NO and Total Thiols, significantly higher (p < 0.05) than in the group treated with lisinopril. The serum levels of tumour necrosis factor-alpha (TNF-α) increased in all groups where HTN was induced. Both doses of GP extract prevented the elevation of TNF-α. Heart tissue levels of the studied cytokines (TNF-α, interleukin (IL)-1β, and IL-6 were not influenced (p > 0.05) by either the HTN induction or the treatment administered.

Conclusions: These findings suggest that grape pomace may serve as a promising nutraceutical intervention for hypertension management, particularly in conditions associated with oxidative stress.