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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #196612
Title: Effect of almond skin polyphenolics and quercetin on human LDL and apolipoprotein B-100 oxidation and conformation

Author
item CHEN, CHUNG-YEN - TUFTS/HNRCA
item Milbury, Paul
item CHUNG, SHIN-KYO - TUFTS/HNRCA
item Blumberg, Jeffrey

Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2006
Publication Date: 12/1/2007
Citation: Chen, C., Milbury, P., Chung, S., Blumberg, J. 2007. Effect of almond skin polyphenolics and quercetin on human LDL and apolipoprotein B-100 oxidation and conformation. Journal of Nutritional Biochemistry. 785-794.

Interpretive Summary: Almond (Prunus dulcis) consumption produces a "heart healthy" profile by reducing plasma low density lipoprotein (LDL) and increasing the intake of vitamin E and monounsaturated fats, actions consistent with prospective observational data showing an inverse correlation between nut intake and risk of cardiovascular disease (CVD). Almond polyphenols with antioxidant activities may contribute to this association. The oxidative modification of LDL appears to play a critical role in development of CVD. Almond skin flavonoids inhibit Cu2+-induced lipid peroxidation in LDL. However, the effect of almond skin flavonoids on apolipoprotein B-100 oxidation and LDL conformation has not been explored. In this study, almond skin flavonoids diminish protein modification and maintain integrity of LDL structure during copper-induced oxidation in a dose-dependent manner. The actions of almond skin flavonoids on these protections are generally at least additive to those of vitamins C and E. Thus, almond skin flavonoids reduce the oxidative modification of apo B-100 in a dose-dependent manner and act in an additive fashion with vitamins C and E.

Technical Abstract: Almond skin flavonoids (ASF) inhibit Cu2+-induced generation of conjugated dienes in low density lipoproteins (LDL). However, the effect of ASF on apolipoprotein B-100 oxidation and LDL conformation has not been explored. ASF (0.12-2.0 µmol/L gallic acid equivalents) were incubated with human LDL and Cu2+. In a dose-dependent manner, ASF reduced the ratio of minimally modified LDL (LDL-) to total LDL (tLDL) by 38.2-83.8% at 5 h. ASF decreased tryptophan oxidation by 6.7-75.7% and increased the generalized polarity of LDL by 21.0-81.5% at 90 min. The actions of ASF on these parameters were generally additive to those of vitamins C and E. However, the combination of ASF with vitamin E produced a 24-43% synergistic reduction in LDL- /tLDL and, with vitamin C, a 10-25% greater resistance against tryptophan oxidation. Thus, ASF reduce the oxidative modification of apo B-100 in a dose-dependent manner and act in an additive or synergistic fashion with vitamins C and E.