The role of anthocyanins in cardiovascular disease
protection is strongly linked to oxidative stress protection.
Since endothelial dysfunction is involved in initiation and
development of vascular disease, four anthocyanins isolated
from elderberries were incorporated into the plasma
lemma and cytosol of endothelial cells to directly examine
the protective roles [34]. These tests demonstrated
not only that anthocyanins could be directly incorporated
into endothelial cells, but that significant oxidative
stress protection was the result. Delphinidin, but not
malvidin or cyanidin, provided endothelium-dependent
vasorelaxation in the rat aorta, providing a pharmacological
benefit comparable to red wine polyphenolics [35].
In a rat model, little influence of feeding purified anthocyanins
(cyanidin 3-O-glucoside) or anthocyanin-rich extracts
from elderberry or blackcurrant could be detected
on cholesterol levels or fatty acid patterns in liver, but the
pigments were capable of sparing vitamin E [36]. Crude
anthocyanin extracts from bilberry have been administered
both orally and via injection to reduce capillary permeability
[13]. In other research related to cardiovascular
impairment, the roles of anthocyanin pigments versus
other flavonoids delivered in the phytochemical extract
have not been completely sorted out. Protection from
heart attacks through administration of grape juice or
wine was strongly tied to the ability of the anthocyaninrich
products to reduce inflammation and enhance capillary
strength and permeability, and to inhibit platelet formation
and enhance nitric oxide (NO) release [37]. Similarly,
delivery of a black currant concentrate with intense
anthocyanin content caused endothelium-dependent vasorelaxation
in rat aorta rings in vitro [38]. The mechanism
of vasorelaxation was attributed to increased levels
of NO production, but the active compounds in the concentrate
were not isolated. When rats were pretreated to
create increased susceptibility to oxidative damage, then
fed anthocyanin-rich extracts, significant reduction in indices
of lipid peroxidation and DNA damage resulted [9].
Ingestion of these extracts, which contained mixtures of
delphinidin, cyanidin, petunidin, peonidin, and malvidin
in the 3-glucopyranoside forms, also increased plasma antioxidant
capacity.