X-Message-Number: 24208
Date: Mon, 7 Jun 2004 17:18:03 -0700 (PDT)
From: Doug Skrecky <>
Subject: coloured sweet potato as a health food

Arch Pharm Res. 2003 Oct;26(10):821-5.
Antioxidant and memory enhancing effects of purple sweet potato
anthocyanin and cordyceps mushroom extract.
The effects of purple sweet potato anthocyanin (SPA) and Cordyceps
mushroom extract (CME) on lipid peroxidation,
1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and cognitive deficits were
examined. Both SPA and CME exhibited DPPH radical scavenging activities
with similar potency. In contrast, only SPA was shown to effectively
inhibit lipid peroxidation initiated by Fe2+ and ascorbic acid in rat
brain homogenates. Furthermore, SPA markedly enhanced cognitive
performance, assessed by passive avoidance test in ethanol-treated mice.
Combined treatments with SPA and CME did not significantly
influence the effects of SPA alone. These results demonstrate that
anthocyanin prepared from purple sweet potato exhibits memory enhancing
effects, which may be associated with its antioxidant properties.

J Agric Food Chem. 2003 Sep 24;51(20):5916-22
Potential chemopreventive properties of anthocyanin-rich aqueous extracts
from in vitro produced tissue of sweetpotato (Ipomoea batatas L.).
Anthocyanin-rich aqueous extracts from cell suspension cultures of a high
anthocyanin-producing sweetpotato PL (purple line) cell line grown under
two different media conditions, MM (multiplication medium) and APM (high
anthocyanin-producing medium) and from the cell line's donor tissue,
field-grown storage root (SR) of sweetpotato, cv. Ayamurasaki, were
evaluated for antioxidative (DPPH test), antimutagenic
(Salmonella/reversion assay; mutagen, Trp-P-1), and antiproliferative
(human promyelocytic leukaemia cells HL-60) activities. Both cell line
extracts MM and APM exhibited higher radical scavenging activities (RSA),
3.8- and 1.4-fold, respectively, than the SR extract. The antimutagenic
activity of all extracts was found to be dose-dependent. At a dose of 1
mg/plate, the highest activity exhibited APM (73% inhibition of
Trp-P-1-induced reverse mutation of Salmonella typhimurium
TA98), followed by MM (54% inhibition) and SR (36% inhibition). The MM
extract was the strongest inhibitor of the proliferation of human
promyelocytic leukemia cells. At a concentration of 1.6 mg/mL medium
during 24 h, it suppressed the growth of 47% of HL-60 cells. A
significantly lower growth suppression effect displayed APM and SR
extracts (21 and 25%, respectively). Total anthocyanin levels and
anthocyanin composition in evaluated samples seem to be related to their
activities. The MM extract, which exhibited the highest RSA and
antiproliferation activities, contained the highest level
of anthocyanins. Among them, nonacylated cyanidin
3-sophoroside-5-glucoside dominated. It is speculated that the presence
of this anthocyanin contributed toward enhanced activities of MM extract.

Eur J Cancer Prev. 2002 Aug;11(4):365-8.
Diet and gallbladder cancer: a case-control study.
Cancer of the gallbladder is rare but fatal, and has an unusual
geographic and demographic distribution. Gallstones and obesity have been
suggested as possible risk factors. As diet is known to influence both
these factors, we carried out the present study to evaluate the possible
role of diet in gallbladder carcinogenesis. A case-control study involving
64 newly diagnosed cases of gallbladder cancer and 101 cases of
gallstones was carried out. The dietary evaluation was carried out by the
dietary recall method based on a preset questionnaire developed
specifically for the present study, keeping in mind the common dietary
habits prevailing in this part of the world. Odds ratios (OR) and 95%
confidence interval (CI) were calculated for various dietary items. A
significant reduction in odds ratio was seen with the consumption of
radish (OR 0.4; 95% CI 0.17-0.94), green chilli (OR
0.45; 95% CI 0.21-0.94) and sweet potato (OR 0.33; 95% CI 0.13-0.83)
among vegetables, and mango (OR 0.4; 95% CI 0.16-0.99), orange (OR; 0.45;
95% CI 0.22-0.93), melon (OR 0.3; 95% CI 0.14-0.64) and papaya (OR 0.44;
95% 0.2-0.64) among fruits. A reduction in odds was also seen with the
consumption of cruciferous vegetables, beans, onion and turnip, however
the difference was not statistically significant. On the other hand, an
increase in the odds was observed with consumption of capsicum (OR 2.2),
beef (OR 2.58), tea (OR 1.98), red chilli (OR 1.29) and mutton (OR 1.2),
however the difference was statistically not significant. In conclusion,
the results of the present study show a protective effect of vegetables
and fruits on gallbladder carcinogenesis, but red meat (beef and mutton)
was found to be associated with increased risk of gallbladder cancer.

J Agric Food Chem. 2004 Mar 24;52(6):1511-3.
In situ and in vitro antioxidant activity of sweetpotato anthocyanins.
Anthocyanins from a variety of fruits and vegetables have been shown to
possess potent antioxidant activity in vitro, but scavenging of free
radicals by anthocyanins has only been demonstrated in situ in the leaves
of certain plants. We report on a new sweetpotato that exhibits mottled
purple flesh attributable to high concentrations of anthocyanins. By
perfusing transverse sweetpotato sections with the reactive oxygen species
H(2)O(2), followed by the H(2)O(2) sensitive fluorochrome scopletin, we
show that anthocyanins act as antioxidants in situ within the sweetpotato
storage roots. We also demonstrate in vitro antioxidant activity by
sweetpotato anthocyanins, where an additive effect with hydroxycinnamic
acids is observed. Anthocyanic foods have been shown to offer protection
against a variety of degenerative disease processes. Given that
sweetpotato can be eaten several hundred grams at a time and as a staple,
these data are consistent with the possibility of superior health
protection by anthocyanic varieties of sweetpotato in comparison to most
common fruits and vegetables.

Mutat Res. 2003 Feb-Mar;523-524:109-17
Potential functional foods in the traditional Maori diet.
The Maori people were early New Zealand settlers of Polynesian descent.
The incidence of non-infectious diseases appears to have been low in
these people, perhaps in part due to the presence of protective chemical
constituents within their food plant supply. Three of the tropical crops
they introduced are still eaten here today: the sweet potato or kumara
(Ipomoea batatas), the taro (Colocasia esculenta) and the cabbage tree or
ti (Cordyline terminalis). Sporamins A and B, the major storage proteins
of kumara tubers, act as proteinase inhibitors, and may have other
anti-cancer properties. The tubers also contain the anti-coagulant
coumarins, scopoletin, aesculetin, and umbelliferone. The corms of taro
contain the anthocyanins, cyanidin 3-glucoside, pelargonidin 3-glucoside
and cyanidin 3-rhamnoside, reported to have antioxidant and
anti-inflammatory properties. Anthocyanins are also major components of a
so-called "Maori potato", a variety officially known as Ureniki, which
has a purple skin and flesh and was widely eaten in the early 1900s.
Anthocyanins are also present in ripe berries of the ramarama
(Lophomyrtus bullata) and rohutu (Neomyrtus pedunculata). Both the leaves
and seeds of the introduced cabbage tree (Cordyline terminalis) and the
native Cordyline spp., C. australis, C. indivisa, and C. pumilo, were
eaten. The seeds of C. australis, of some Astelia spp., and of hinau
(Elaeocarpus dentatus) are good sources of various essential fatty acids,
generally regarded as protective against cardiovascular disease. Shoots
and leaves from a wide range of native species were traditionally eaten
as greens, especially "sow thistle" or puha (Sonchus spp.), reportedly
high in Vitamin C and various phenolics. "New Zealand spinach"
(Tetragonia tetragonioides or T. expansa) has anti-ulcerogenic activity
that has been traced to two cerebrosides and anti-inflammatory activity
that has been traced to novel water-soluble polysaccharides, as well as
antioxidant phenylpropanoids including caffeic acid. Leaves of the "hen
and chickens" fern (Asplenium bulbiferum) contain antioxidant flavonoids
such as kaempferol glucosides. Native seaweeds also have useful nutritive
properties.

J Agric Food Chem. 2003 May 21;51(11):3313-9.
Stoichiometric and kinetic studies of phenolic antioxidants from Andean
purple corn and red-fleshed sweetpotato.
Stoichiometric and kinetic values of phenolics against DPPH
(2,2-diphenyl-1-picrylhydrazyl) were determined for Andean purple corn
(Zea mays L.) and red sweetpotato (Ipomoea batatas). Both crops had
higher antioxidant capacity and antiradical kinetics than blueberries and
higher or similar anthocyanin and phenolic contents. The second-order rate
constant (k(2)) was 1.56, 1.12, 0.57, and 0.26 (mg antiradical/mL)(-1)
s(-1) for red sweetpotato, Trolox, purple corn, and blueberry,
respectively. On the molar basis of active hydroxyl groups, k(2)' showed
the same order as for k(2). Corn cob and sweetpotato endodermis
contributed the most in phenolic compounds and antioxidant capacity. Both
crops studied can be considered as excellent novel sources of natural
antioxidants for the functional food and dietary supplement markets.

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