Agriculture Reference
In-Depth Information
was more abundant in the peel (158 mg/100 g, dry-wt) than
in the pulp (29.6 mg/100 g, dry-wt); it was suggested that
the antioxidant potential of these bananas may be due to
the high gallocatechin content (Someyaa et al., 2002).
on the mouse left atrium had been inhibited by flavonoids,
7-monohydroxy
71,3,
4
-
ethyl
rutoside,
and
trihydroxyethyl rutoside (Huesken et al., 1995).
Another animal study involving guinea pigs tested dif-
ferent flavonoids for a positive inotropic effect on guinea
pig papillary muscle, and the results showed that quercetin
possessed the highest potent intrinsic activity and pro-
duced the strongest inotropic responses among the dif-
ferent flavonoids. The relative order of potency of the
tested flavonoids was quercetin
>
morin
=
kaempferol
>
luteolin
=
apigenin
>
fisetin
=
galangin (Itoigawa et al.,
1999). Flavonoids have been shown to exhibit protection
against LDL cholesterol oxidation by reducing free rad-
icals, metallic ion chelation, and
Carotenoids
The effect of the antioxidant activity of
β
-carotene and
related carotenoids on the oxidation of free radical of
methyl linoleate in solution was examined by Terao (1989),
and results showed that canthaxanthin and astaxanthin,
which possess oxo groups at the 4- and 4
-positions in the
β
-inonone ring, retarded the hydroperoxide formation more
efficiently than
β
-carotene and zeaxanthin which possess
no oxo groups. The rates of autocatalytic oxidation of can-
thaxanthin and astaxanthin were also slower than those of
β
-tocopherol regenera-
tion. They also inhibit red cell aggregation, reducing car-
diopathies, thromboses, and estrogen synthesis (German
and Dillard, 2000).
α
-carotene and zeaxanthin.
During a study to examine the ability of dietary sup-
plementation with carotenoids to protect chick tissues
against oxidative stress
in vitro
, it was found that animals
given
Carotenoids
In a study using J-774 A.1 macrophage cell line, lycopene
as well as
-carotene, or zeaxanthin had a re-
duced susceptibility to oxidative stress in liver compared
with unsupplemented controls. Furthermore,
α
-tocopherol,
β
β
-carotene suppressed 60-70% of cholesterol
synthesis
by
acetate
and
were
implicated
as
moder-
-tocopherol-
supplemented animals had reduced susceptibility in skeletal
muscle compared with unsupplemented controls (Woodall
et al., 1996).
The antioxidant activity of
α
ate
hypocholesteremic
agents
(Fuhramn
et
al.,
1997).
β
-carotene and canthaxanthin altered the pro-oxidation
and antioxidation balance and suppressed cholesterol-
induced oxidative stress in rats fed on a high-cholesterol
and high-fat diet. The suggested mechanism for these
carotenoids is via modulation of the antioxidant system
and cholesterol metabolism.
-carotene, lutein, canthax-
anthin, and astaxanthin was investigated during spon-
taneous and peroxyl radical-induced cholesterol oxida-
tion by Palozza et al. (2008). They reported that all the
carotenoids tested exhibited significant antioxidant activity
by inhibiting spontaneous 2,2
-azobois (2-amidinopropane)
dihydrochloride (AAPH) and 2,2
azobis-isobutyronitrile
(AIBN) induced formation of 7-keto-cholesterol (7-KC).
The overall order of efficacy of these compounds was as-
taxanthin
β
Dietary fiber
Overall evidence indicates that soluble fibers lower plasma
cholesterol levels. Although the mechanism for this effect
is not clearly understood, the most common explanation
is that increased viscosity in the gastrointestinal contents
interferes with micelle formation and lipid absorption. It
was also suggested that increased sterol excretion is re-
sponsible for cholesterol-lowering effects of fiber. Certain
dietary fibers can bind bile salts and neutral sterols (Story,
1986) and enhance their removal from the body as studies
in rats showed that fibers that reduced plasma cholesterol
increased neutral sterol or bile acid excretion (Arjmandi
et al., 1992).
>
>
=
β
-carotene. These
findings showed that carotenoids exert protective effects
on spontaneous and free radical-induced cholesterol oxi-
dation, which may provide important beneficial effects to
human health.
canthaxanthin
lutein
Coronary heart disease
Phenolics
Animal studies involving guinea pigs have concluded that
3-methyl quercetin has positive chronotropic effect on the
right atrium and antiarrhythmic effect on the left atrium
in guinea pig (Lackeman et al., 1986). In his review,
Huesken et al. (1995) gave detailed discussion on the car-
dioprotective effects of flavonoids. They indicated that the
cardiotoxicity (negative inotropic effect) of doxorubicin
Plant sterols
Plant sterols are assumed to be hydrolyzed in the gut
by sterolester hydrolase, and the resulting different frac-
tions are stipulated to have lowering effects on the choles-
terol absorption in the human small intestines (Swell
et al., 1954), thus making plant sterols having serum
Search WWH ::
Custom Search