The Instituto del Frío in Madrid made a review study about the effect of anthocyanins on cardiovascular health . According to the lead author Sonia de Pascual-Teresa the beneficial biological effects of anthocyanins may be driven by their affinity for proteins and their antioxidant activity. Many publications have shown that anthocyanins may regulate different signalling pathways involved in cell survival, growth and differentiation. The bioavailability of anthocyanins has always been assumed to be very low, but not all metabolites have yet been identified and could included compounds such as gallic acid, protocatechuic acid, syringic acid, phloroglucinol and vanillic acid. Anthocyanins can act on different cells involved in the development of arthrosclerosis. Anthocyanins have been shown to reduce the secretion of chemokine monocyte chemotactic protein 1, a protein that recruits monocytes to inflammation sites. The anthocyanins delphinidin and cyanidin have been shown to prevent the expression of vascular endothelial growth factor, a compound that has stimulates atherosclerosis. Other favourable effects of anthocyanins are relaxation of arteries, distribution of cholesterol, reduction on NO production and protection against ischemia injury.
A study conducted at the Military Medical Academy, Poland., found that anthocyanins from chokeberry decrease lipid peroxidation and concluded that these anthocyanins may be potentially used to reduce oxidative stress . Kowalczyk and his team investigated the effects of anthocyanins from chokeberry, also called aronia, on some parameters of oxidation-reduction balance in rats. They found that the anthocyanins reduced the content of thiobarbituric acid reactive substances and thiol protein groups.
On the other hand, Curtis and co-workers at the University of East Anglia, Norwich, UK, found that the intake of 500 mg/d of elderberry extract for 12 weeks did not significantly changed cardiovascular disease risk biomarkers in postmenopausal women . They came to this conclusion after conducting a randomized, placebo-controlled study, examining the effect of chronic consumption of anthocyanins on biomarkers of cardiovascular disease risk in 52 healthy postmenopausal women.
 Flavanols and anthocyanins in cardiovascular health: a review of current evidence. Int J Mol Sci. 2010 Apr 13;11(4):1679-703.
 Anthocyanins--an adjunct to cardiovascular therapy? Kardiol Pol. 2002 Oct;57(10):332-6.
 Cardiovascular disease risk biomarkers and liver and kidney function are not altered in postmenopausal women after ingesting an elderberry extract rich in anthocyanins for 12 weeks. J Nutr. 2009 Dec;139(12):2266-71.