47
called “French paradox”, namely the negative correlation observed between moderate red wine consumption and
CHD incidence (Burns
et al
., 2000). Further studies have shown the chemopreventive properties of phenolic
components of wine, and in particular of flavonoids and stilbenoids, in countering cancer and other degenerative
diseases associated with oxidative or inflammatory processes (Soleas
et al
., 2002).
The investigations of chemical constituents of grape pomace have shown the presence of polyphenols,
identified also in red wine, mainly anthocyanins, flavonols, flavonol glycosides, and phenolic acids (Torres
et al
.,
2002). Also, less common compounds have been identified, which may have originated from seeds and stems or
formed in biotransformations during winemaking (Torres
et al
., 2002). These data suggest that grape pomace, if
conveniently processed, could furnish useful products that may balance out waste treatment costs. However, a
significant variability in quantitative and qualitative distribution of chemical constituents in grape pomace has to
be expected depending on an array of important factors, such as the varietal differences of
V. vinifera
, the location
of cultures and the wine-making procedures (destemming, crushing, maceration and pressing) (Cantos
et al
.,
2002).
Recently, the relationship between apoptosis and cancer has been intensively studied, with apoptotic
pathways (Hata
et al
., 2002). The maintenance of homeostasis in normal mammalian tissues reflects a critical
balance between cell proliferation and cell death via apoptosis (Hata
et al
., 2002). In contrast, apoptosis may be
inhibited or perturbed in tumors in which the rate of cell proliferation exceeds that of cell loss. If misregulation of
apoptosis results in a failure of tissue size regulation, which eventually leads to the malignant transformation,
apoptotic cell death could be induced to augment interventions designed to suppress or reverse the development of
cancer (Thompson, 1995).
In the past few years, there has been an increasing interest in relevant dietary sources as
chemopreventive agents; however, phytochemical properties from Shiraz red grape, especially pomace extract in
which an anticancer treatment has no reports. This study focused on its pomace extract to determine their phenolic
compounds and to elucidate the radical scavenging properties. Moreover, the expressions of apoptotic proteins in
cancer cells induced by pomace extract was evaluated. This study was hopefully expected that the pomace extract
might consider to be added-value by-products. The detected effects of Shiraz pomace extract could be also a
potential natural source as anticancer treatment.
Materials and methods
Extraction
Whole grapes were squeezed to prepare pomace (skin and seed). Pomace was dried in hot-air oven at
50
°
C for 72 h and powdered in a blender for 1 min at maximal speed then divided into smaller aliquots and frozen
at -20°C until use. Pomace (100 g) was extracted into 2 cycles in 70% (v/v) ethanol at 60
°
C, 48 h and reused 70%
(v/v) ethanol at 60
°
C, 8 h, respectively by using Büchi B-811
universal extraction system. The ethanolic pomace
extract was evaporated, lyophilized and stored at -80
°
C for further investigation.
