Isothiocyanates and freeze-dried strawberries as inhibitors of esophageal cancer.
Toxicological Sciences.1999 December;52
The purpose of this in vivo study was to investigate the ability of isothiocyanates to inhibit tumorigenicity and DNA methylation induced by the carcinogen N-nitrosomethylbenzylamine. The researchers found that, of all the tested isothiocyanates, phenylpropyl isothiocyanate had the strongest inhibitory effect on esophageal tumorigenesis. The isothiocyanates with two or three carbons seemed more effective than the longer chained isothiocyanates. A strawberry preparation also inhibited esophageal tumorigenesis, but to a lesser degree than phenylpropyl isothiocyanate. The study concluded that not only the well known phytochemical ellagic acid but also other phytochememicals, such as isothiocyanates, may explain the chemopreventive action of strawberries.
Antioxidant levels and inhibition of cancer cell proliferation in vitro by extracts from organically and conventionally cultivated strawberries.
Journal of Agricultural and Food Chemistry. 2006 February 22;54(4):1248-55
The aim of this study was to investigate the effects of strawberry extracts on the growth of cultivated colon cancer cells and breast cancer cells. The influence of the cultivation method, organic versus conventional, was also investigated. The researchers found that the ascorbic acid to dehydroascorbic acid was significantly higher in the organically cultivated strawberries. The strawberry extracts decreased the growth of both cancer cell lines in a dose-dependent way. The extract from the organically grown strawberries showed the highest inhibition on cancer cell growth.
Inhibitory effect on activator protein-1, nuclear factor-kappaB, and cell transformation by extracts of strawberries.
Journal of Agricultural and Food Chemistry. 2005 May 18;53(10):4187-93
The purpose of this study was to investigate the influence antioxidant enzymes in strawberry extract. The effect were determined by measuring the activities of activator protein-1 and nuclear factor-kappaB induced by a carcinogen (tetradecanoylphorbol-13-acetate) or ultraviolet-B radiation. The influence of strawberry extracts on the growth and transformation of cancer cells were also evaluated. The researchers found that strawberry extracts inhibited the growth of lung cancer cells and reduced the transformation of epidermal cells after treatment with the carcinogen. Strawberry extract also inhibited activator protein-1 and nuclear factor-kappaB after treatment with tetradecanoylphorbol-13-acetate or UVB radiation. The study concluded that strawberries may be used as a chemopreventive agent.
Inhibitory effect of whole strawberries, garlic juice or kale juice on endogenous formation of N-nitrosodimethylamine in humans.
Cancer Letters. 2002 August 8;182(1):1-10
Carcinogenic nitrosamines can be formed in the stomach after consumption meals rich in nitrate and amines - for example combination of spinach and fish. The purpose of this study was to investigate if consumption strawberries, garlic or kale could prevent this nitrosation. About forty volunteers participated in this study. The researchers found that strawberries, garlic juice or kale juice, when eaten after the amine- and nitrate-rich diet decreased N-nitrosodimethylamine production considerable. The study concluded that the consumption of consumption of strawberries, garlic juice or kale juice could reduce formation of carcinogenic nitrosamonines.
Inhibition of N-nitrosomethylbenzylamine-induced tumorigenesis in the rat esophagus by dietary freeze-dried strawberries.
Carcinogenesis. 2001 March;22(3):441-6
The aim of this in vivo study was to investigate if freeze-dried strawberries could inhibit esophageal cancer formation induced by the carcinogen N-nitrosomethylbenzylamine. The researchers found that rats which received a diet consisting of 10 percent of freeze-dried strawberries had up to 56 percent less esophageal cancer multiplicity. Rats which were fed with strawberries showed considerably lower levels of O6-methylguanine in their esophageal DNA, suggesting that phytochemicals in strawberries interfere with the metabolism of N-nitrosomethylbenzylamine. Treatment of the rats with the carcinogen N-nitrosomethylbenzylamine followed by feeding of freeze-dried strawberries also reduced cancer multiplicity. The study concluded that freeze-dried strawberries inhibit N-nitrosomethylbenzylamine-induced tumorigenesis.
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