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cell proliferation (%) depended on dose and time. To investigate the effects of pomace extract-induced apoptosis
in MCF-7, the morphologically monitored by nuclear fragment and DNA fragments as well as the apoptotic
proteins were evaluated by immunodetection in Western blotting. After 5 hours of the incubation with pomace
extract, the nuclei of treated cells were fragmented with blebbing and the ladder-like DNA fragments. Pomace
extract increased the apoptotic 50% cells. Pomace extract induced the expressions of p53 (53 kDa) apoptotic
proteins and reduced the expressions of Bcl-2 (26 kDa). Overall, the present data suggest that pomace extract has a
high and real potential as a safe and effective of natural antioxidants with many pharmaceutical properties. This
study espectially expected that pomace extract might consider to be added-value by-products and to be developed
as natural anticancer agents or nutraceuticals in the future.
Keywords:
Grape pomace extract, Apoptosis, Human breast cancer cells
Introduction
Many classes of phytochemicals from natural compounds exert antioxidant activities as well as other
beneficial effects, for example, on the inflammatory responses, on cellular enzymatic detoxification systems and
on proliferative and anticancer properties (Teel, 1992). Among fruits, grapes constitute one of the major sources of
total phenolic compounds. Grape pomace is also rich in phenols (Yildrim
et al
., 2005). Grape, one of the world’s
largest fruit crops which approximates an annual production more than 60 million metric tons is cultivated mainly
as
Vitis vinifera
for wine production. Grape berries are consumed as table fruit, wine, juice, and raisins.
Before 1960, grapes were imported from the United State and Australia to Thailand, incurring high
costs. At present, there are over 8 million hectares worldwide and 2,717 ha producing 31,677 tones/year with an
average yield of about 15 t/ha in Thailand. Wine industry wastes account for almost 30% (w/w) of the grapes used
for wine production (Makris
et al
., 2007). The pomace, by-product of wine making, consisting of skins and seed,
and sometimes stems and leaves has the potential to be a rich source of the antioxidants that are becoming more
and more popular in the food and health industries compared with other agri-food solid wastes. The worldwide
amount of grape pomace, from the wine and juice industries, averages about seven to nine million tons per year
(Baumgartel
et al
., 2005). These waste materials contain biodegradable organic matter; however, their disposal
generates huge amounts of industrial waste and creates serious environmental problems. The waste loads at the
processing plants could be significantly reduced through by-product usage (Morthup
et al
., 1998). On the other
hand, it is known that grape pomace is a rich source of polyphenols possessing beneficial effects on human health
(Torres et al., 2002).
The available studies on grape pomace are relatively scarce in comparison with those carried out on wine
components (Makris
et al
., 2007). Indeed, a variety of epidemiological, clinical and
in vitro
studies have been
carried out in support of the positive role of wine polyphenols (resveratrol, an important stilbene found in grapes,
was resolved with the identification) in preventing CHD (Cardiovascular Health Diseases), starting from the so-
