The Benefits of Muscadine Grape Seeds
A couple of patients have told me they have been taking muscadine for years. Apparently these seeds have more antioxidants than other usual sources of antioxidants.
Below is the research I could find on these potentially interesting antioxidant power-sources.
Sandra Lora Cremers, MD, FACS
This was the best article I could find thus far:
The phytochemical resveratrol contained in red grapes has been shown to inhibit prostate cancer cell growth, in part, through its antioxidant activity. Muscadine grapes contain unique phytochemical constituents compared with other grapes and are potentially a source for novel compounds with antitumor activities. We compared the antitumor activities of muscadine grape skin extract (MSKE), which we show contains no resveratrol, with that of resveratrol using primary cultures of normal prostate epithelial cells (PrEC) and the prostate cancer cell lines RWPE-1, WPE1-NA22, WPE1-NB14, and WPE1-NB26, representing different stages of prostate cancer progression. MSKE significantly inhibited tumor cell growth in all transformed prostate cancer cell lines but not PrEC cells. Prostate tumor cell lines, but not PrEC cells, exhibited high rates of apoptosis in response to MSKE through targeting of the phosphatidylinositol 3-kinase–Akt and mitogen-activated protein kinase survival pathways. The reduction in Akt activity by MSKE is mediated through a reduction in Akt transcription, enhanced proteosome degradation of Akt, and altered levels of DJ-1, a known regulator of PTEN. In contrast to MSKE, resveratrol did not induce apoptosis in this model but arrested cells at the G1-S phase transition of the cell cycle associated with increased expression of p21 and decreased expression of cyclin D1 and cyclin-dependent kinase 4 proteins. These results show that MSKE and resveratrol target distinct pathways to inhibit prostate cancer cell growth in this system and that the unique properties of MSKE suggest that it may be an important source for further development of chemopreventive or therapeutic agents against prostate cancer. [Cancer Res 2007;67(17):8396–405]
Where did they get it?
Chemicals and preparation of MSKE. Resveratrol, DMSO, propidium iodide, and Z-leu-leu-leu-al (MG132 proteosome degradation inhibitor) were purchased from the Sigma Chemical. Dried and pulverized muscadine grape skin was obtained from Muscadine Products Corporation. The muscadine skin powder was prepared from the Ison cultivar, a purple-skinned variety. Similarly, dried and ground muscadine ground seeds from the Ison variety were used for the muscadine seed extract. A single, large preparation of MSKE was used for all experiments in this study. Polyphenolic compounds from the dried and pulverized muscadine grape skin were extracted with 50% ethanol/water at a nominal ratio of 9:1 (v/w) by stirring with a magnetic stir bar for 1 h at room temperature. The slurry was allowed to settle for 24 h, and the supernatant was passed through a 0.2 μmol/L membrane filter funnel (Nalgene) and collected under a vacuum.
More info below:
The muscadine grape (Vitis rotundifolia) is a grape variety that is well adapted to the warm humid climate of the southeast United States. These grapes contain a distinct composition of polyphenols relative to other grape varieties, which is characterized by high concentrations of gallic acid and abundant flavan-3-ols, flavonols, anthocyanins, and ellagic acid. Despite the unique biochemical composition of muscadines, relatively little is known about the potential cardiovascular effects of dietary supplements with muscadine grape seeds or other muscadine-derived food supplements.
The current study was designed to examine the effects of a commercially available muscadine grape seed food supplement (Nature’s Pearl) on vascular function and cardiovascular risk factors in subjects with, or at risk for, cardiovascular disease. For the purpose of this study, resting brachial artery diameter and brachial FMD measured using standardized 2-dimensional ultrasound protocols were used as simple noninvasive measures of resting vasomotor tone and endothelial-dependent vasodilator capacity.
Published in final edited form as:
J Am Coll Nutr. 2010 Oct; 29(5): 469–475.
Effect of Muscadine Grape Seed Supplementation on Vascular Function in Subjects with or at Risk for Cardiovascular Disease: A Randomized Crossover Trial
See other articles in PMC that cite
the published article.
Phenolic content and antioxidant capacity of muscadine grapes.
Fruits of 10 cultivars of muscadine grapes (five bronze skin and five purple skin) grown in southern Georgia were separated into skin, seed, and pulp. Each fruit part and the leaves from the corresponding varieties were extracted for HPLC analysis of major phenolics. Total phenolics were determined colorimetrically using Folin-Ciocalteu reagent. Total anthocyanins were determined according to a pH-differential method, using a UV-visible spectrophotometer. Antioxidant capacity was determined by the Trolox equivalent antioxidant capacity (TEAC) assay. Gallic acid, (+)-catechin, and epicatechin were the major phenolics in seeds, with average values of 6.9, 558.4, and 1299.4 mg/100 g of fresh weight (FW), respectively. In the skins, ellagic acid, myricetin, quercetin, kaempferol, and trans-resveratrol were the major phenolics, with respective average values of 16.5, 8.4, 1.8, 0.6, and 0.1 mg/100 g of FW. Contrary to previous results, ellagic acid and not resveratrol was the major phenolic in muscadine grapes. The HPLC solvent system used coupled with fluorescence detection allowed separation of ellagic acid from resveratrol and detection of resveratrol. Reported here for the first time are the phenolic content and antioxidant capacity of muscadine leaves. Major phenolics in muscadine leaves were myricetin, ellagic acid, kaempferol, quercetin, and gallic acid, with average concentrations of 157.6, 66.7, 8.9, 9.8, and 8.6, respectively. Average total phenolics were 2178.8, 374.6, 23.8, and 351.6 mg/g gallic acid equivalent in seed, skin, pulp, and leaves, respectively. Total anthocyanin contents were 2.1 and 132.1 mg/100 g of FW in the skins of bronze and purple grapes, respectively, and 4.3 and 4.6 mg/100 g of FW in seeds and pulps, in that order. Antioxidant capacity values were, on average, 2.4, 12.8, 281.3, and 236.1 microM TEAC/g of FW for pulps, skins, seeds, and leaves, respectively.