Inhibitory effects of grape seed procyanidins on foam cell formation in vitro.
ABSTRACT Human and animal studies have demonstrated that procyanidin-rich diets reduce the risk of cardiovascular diseases and atherosclerosis. Some beneficial effects have been attributed to the well-known antioxidant activity of procyanidins. This study investigated another potential corrective role of procyanidins in cholesterol flux and inflammation in macrophage-derived foam cells. RAW 264.7 macrophages were cultured with moderately oxidized LDL (oxLDL), minimally oxidized LDL (moxLDL), or LPS (0.5 microg/mL) and oxLDL (LPS + oxLDL) to induce foam cells. Then, cells were treated with procyanidins derived from grape seed (PE, 45 microg/mL) for the last 12 h of incubation with the different lipoproteins (25 microg/mL). After lipid extraction, it was determined that total and esterified cholesterol and triglyceride accumulations in foam cells were increased by lipoprotein treatment but reduced by PE incubation. To asses the effect of PE on gene expression, the relative mRNA levels of CD36, ABCA1, iNOS, COX-2, and IkappaBalpha were determined by RT-PCR. It was shown that PE reduced the oxLDL scavenger receptor expression (CD36) and enhanced ATP-binding cassette A1 (ABCA1) expression, a key regulator of macrophage cholesterol efflux. PE also down-regulated inflammatory-related genes such as inducible nitric oxide synthase (iNOS) and kappa beta inhibitor-alpha (IkappaBalpha) without modifying COX-2 expression. In conclusion, evidence is provided that procyanidins may attenuate the development of foam cell formation by reducing cholesterol accumulation and modulating the expression of key genes in cholesterol flux and inflammation.
Article: Postprandial blood glucose response to grape seed extract in healthy participants: A pilot study.[show abstract] [hide abstract]
ABSTRACT: The consumption of a high carbohydrate diet may be associated with an increased risk of type 2 diabetes and obesity. Previous studies in vitro have revealed that grape seed extract (GSE) inhibited the intestinal α-glucosidases and α-pancreatic amylase that may delay carbohydrate digestion and absorption, resulting in the suppression of postprandial glycemia. The objective of the study was to assess whether consumption of GSE together with high carbohydrate meal affects postprandial glycemia in healthy participants. The study used acute, randomized, controlled crossover design in which eight healthy subjects (four female and four male, mean aged 21.25 ± 3.69 years; body mass index =20.28 ± 1.40 kg/m(2)) received high carbohydrate (HC) meal (73.6 %) together with or without 100 and 300 mg GSE. Results showed that postprandial plasma glucose concentrations at 15 min and 30 min after ingestion HC meal together with 100 mg GSE (5.33 ± 0.41 mmol/L and 5.62 ± 0.47 mmol/L, respectively) and 300 mg GSE (5.27 ± 0.29 mmol/L; 5.75 ± 0.44 mmol/L, respectively) were significantly lower than that of HC meal (P<0.05). There was statistically significant difference in the 2 h area under the glucose response curve between HC meal and HC meal plus GSE. GSE reduces postprandial plasma glucose in healthy participants. The delayed and attenuated hyperglycemia may have a useful strategy to prevent development of diabetes in the healthy population.Pharmacognosy Magazine 07/2012; 8(31):192-6. · 1.16 Impact Factor