Wine lees and their derived products to manage hypertension. Identification of their bioactive compounds and underlying mechanisms

Identifier:  TDX:3805

Handle: https://hdl.handle.net/20.500.11797/TDX3805

Authors:  López Fernández, Raúl

Abstract:
Hypertension (HTN) is currently one of the major risk factors for cardiovascular disease. Natural antihypertensive compounds are considered as a good strategy in decreasing blood pressure (BP). An interesting source of natural BP-lowering compounds are agri-food industries, which generate large amounts of by-products. This thesis aims to evaluate the potential of wine lees (WL), a winery by-product, as source of antihypertensive compounds. The BP-lowering properties of different WL were studied. WL from the Cabernet grape variety exhibited antihypertensive effect in spontaneously hypertensive rats (SHR) after acute administration. Their effects were associated to their high content in flavanols and anthocyanins. Additionally, these WL were submitted to enzyme-assisted extraction with Flavourzyme to release the phenolic compounds from WL non-soluble fraction and phenolic-enriched WL were obtained. Anthocyanins and flavanols were the largest families present in the hydrolyzed WL, which also exhibited enhanced antioxidant and antihypertensive activities. In addition to phenolic compounds, the hydrolysis also produced the release of the novel antihypertensive peptides FKTTDQQTRTTVA, NPKLVTIV, TVTNPARIA, LDSPSEGRAPG and LDSPSEGRAPGAD. However, original WL also contain ethanol, which disappears in the drying process. Considering that the drying process of WL is essential for their commercialization, the antihypertensive activity of dried WL was investigated. WL powder showed enhanced antihypertensive properties after their acute administration at the most effective dose of 125 mg/kg bw. Their vasoprotective and antioxidant effects were confirmed as the mechanisms involved in their BP-lowering properties. However, since HTN is a chronic disease, the antihypertensive effect of dried WL was also confirmed in SHR. In addition, dried WL reduced heart rate and increased locomotor activity. Therefore, the WL from the Cabernet grape variety, the obtained phenolic-enriched WL, the identified antihypertensive peptides and the dried WL could be good candidates to be included in functional food, nutraceutical and food supplement for the management of HTN.