Grapefruit Seed extract supplement review of benefits
October 27 2015 by Ray Sahelian, MD

Antioxidant benefit
Nutr J. 2015. Effect of consuming a grape seed supplement with abundant phenolic compounds on the oxidative status of healthy human volunteers. Diverse enzymatic and non-enzymatic antioxidants provide protection against reactive oxygen species in humans and other organisms. The nonenzymatic antioxidants include low molecular mass molecules such as plant-derived phenols. This study identified the major phenolic compounds of a grape seed extract by HPLC and analyzed the effect of consumption of biscuits enriched with this extract on the urinary oxidative status of healthy subjects by measurement of urine redox potential. The major phenolic compounds were characterized in a red grape seed extract separated by HPLC with detection by a photodiode array (PDA), fluorescence (FL) and quadrupole mass spectrometer (MS). A nutritional study in a healthy volunteers group was done. Each volunteer ate eight traditional biscuits with no red grape seed extract supplementation. The second day each volunteer ate eight traditional biscuits supplemented with 0.6% (wt/wt) of grape seed extract. An overnight urine sample was obtained for each treatment. The redox potential was measured at 25 C using a potentiometer in each urine sample. Epicatechin, catechin, procyanidin dimers B1 to B4, and the procyanidin trimer C2 were the major phenolic components in the extract. Epicatechin gallate and procyanidin dimers B1-3-G and B2-3'-G were the major galloylated flavan-3-ols. The forty-six healthy volunteers each shown a reduction of the urine redox potential after the treatment by traditional biscuits supplemented with the grape seed extract. This simple dietary intervention significantly reduced (33%) the urine redox potential, reflecting an overall increase in antioxidant status. Incorporation of plant-derived phenols in the diet may increase anti-oxidative status.

Antimicrobial activity
Carbohydr Polym. 2014 Feb 15. Antimicrobial and physical-mechanical properties of agar-based films incorporated with grapefruit seed extract. The use of synthetic petroleum based packaging films caused serious environmental problems due to their difficulty in recycling and poor biodegradability. Therefore, present study was aimed to develop natural biopolymer-based antimicrobial packaging films as an alternative for the synthetic packaging films. As a natural antimicrobial agent, grapefruit seed extract (GSE) has been incorporated into agar to prepare antimicrobial packaging film. The films with different concentrations of GSE were prepared by a solvent casting method and the resulting composite films were examined physically and mechanically. In addition, the films were characterized by FE-SEM, XRD, FT-IR and TGA. The incorporation of GSE caused increase in color, UV barrier, moisture content, water solubility and water vapor permeability, while decrease in surface hydrophobicity, tensile strength and elastic modulus of the films. As the concentration of GSE increased from 0.6 to 13.3μg/mL, the physical and mechanical properties of the films were affected significantly. The addition of GSE changed film microstructure of the film, but did not influence the crystallinity of agar and thermal stability of the agar-based films. The agar/GSE films exhibited distinctive antimicrobial activity against three test food pathogens, such as Listeria monocytogenes, Bacillus cereus and Escherichia coli. These results suggest that agar/GSE films have potential to be used in an active food packaging systems for maintaining food safety and extending the shelf-life of the packaged food.

Inquiries
I noticed grapefruit seed extract listed in your index. I have used cleanses previously (e.g., Paragone) that include this supplement. I picked up some Nutribiotic brand to use for cleansing purposes. Yesterday, I found a site that reported that research findings showed additives were detected to make this particular brand more antibacterial, etc. Any advice whether I should continue taking this supplement?
   A. I have not studied grapefruit seed extract in much detail.

Q. I want to try Diet Rx but noticed that it had Grapefruit seed extract in it. I also take Lipitor (10 mg daily )which you are not supposed to take grapefruit with. Is the grapefruit extract in the Diet Rx safe to take with Lipitor?
   A. The amount of grapefruit seed extract in Diet Rx is very small and should not interfere with the LIpitor but the final decision as to the use of this product together with LIpitor rests with your doctor. When a person eats less as a result of using Diet Rx, their cholesterol level may drop and thus it is possible the dosage of Lipitor could be reduced.