No abstract

Epidemiological studies have revealed that high consumption of soy products is associated with low incidences of hormone-dependent cancers, including breast and prostate cancer. Soybeans contain large amounts of isoflavones, such as the genistein and daidzain. Previously, it has been demonstrated that genistein, one of the predominant soy isoflavones, can inhibit several steps involved in carcinogenesis. It is suggested that genistein possesses pleiotropic molecular mechanisms of action including inhibition of tyrosine kinases, DNA topoisomerase II, 5α-reductase, galectin-induced G2/M arrest, protein histidine kinase, and cyclin-dependent kinases, modulation of different signaling pathways associated with the growth of cancer cells (e.g., NF-κB, Akt, MAPK), etc. Moreover, genistein is also a potent inhibitor of angiogenesis. Uncontrolled angiogenesis is considered as a key step in cancer growth, invasion, and metastasis. Genistein was found to inhibit angiogenesis through regulation of multiple pathways, such as regulation of VEGF, MMPs, EGFR expressions and NF-κB, PI3-K/Akt, ERK1/2 signaling pathways, thereby causing strong antiangiogenic effects. This review focuses on the antiangiogenic properties of soy isoflavonoids and examines their possible underlying mechanisms.

Phenolic compounds from plants are known for their antioxidant properties and have been proposed as therapeutic agents to counteract oxidative stress. However, under normal circumstances, the body only receives a very small amount of these substances in the diet. We have investigated the effect of extracts from known and frequently used plants as part of diet, food seasoning, medicinal tea, and sweetener at different concentrations on the ability to scavenge free radicals, to affect antioxidant enzymes, and finally in the survival of cancer cell lines. We found extract concentrations of about 100 μg.ml(-1) more indicative in the assessment of all parameters investigated. Ginseng possessed a very good ability to scavenge superoxide and hydroxyl radicals, while stevia also manifested significant effects against hydroxyl radicals. Both extracts also showed NO decomposition ability. The antioxidant defense system against the excessive production of radicals in mitochondria was sufficient. In contrast, the range of operating concentrations for sage and oregano mainly presented no significant effects against reactive oxygen and nitrogen species. Taken together with the significantly reduced activity of glutathione peroxidase, this led to the depletion of glutathione. The demonstrated modulation of redox state capability was sufficient to affect the viability of all tested cancer cell lines, but especially A-549, CEM and HeLa by oregano extract. Results support the promising role of the tested extracts as a source of compounds for further in vivo studies with the ability to powerfully interfere with or modify the redox state of cells according to the type of disease, which is expected to be associated with oxidative stress.

Chalcones are naturally occurring phytochemicals with diverse biological activities including antioxidant, antiproliferative, and anticancer effects. Some studies indicate that the antiproliferative effect of chalcones may be associated with their pro-oxidant effect. In the present study, we evaluated contribution of oxidative stress in the antiproliferative effect of acridine chalcone 1C ((2 E)-3-(acridin-9-yl)-1-(2,6-dimethoxyphenyl)prop-2-en-1-one) in human colorectal HCT116 cells. We demonstrated that chalcone 1C induced oxidative stress via increased reactive oxygen/nitrogen species (ROS/RNS) and superoxide production with a simultaneous weak adaptive activation of the cellular antioxidant defence mechanism. Furthermore, we also showed chalcone-induced mitochondrial dysfunction, DNA damage, and apoptosis induction. Moreover, activation of mitogen activated phosphokinase (MAPK) signalling pathway in 1C-treated cancer cells was also observed. On the other hand, co-treatment of cells with strong antioxidant, N-acetyl cysteine (NAC), significantly attenuated all of the above-mentioned effects of chalcone 1C, that is, decreased oxidant production, prevent mitochondrial dysfunction, DNA damage, and induction of apoptosis, as well as partially preventing the activation of MAPK signalling. Taken together, we documented the role of ROS in the antiproliferative/pro-apoptotic effects of acridine chalcone 1C. Moreover, these data suggest that this chalcone may be useful as a promising anti-cancer agent for treating colon cancer.

The intestinal microflora plays a crucial role in the health of humans and animals. All functions of the absorption of nutrients are connected with the valid digestive tract. Approximately 70% of the immune function is derived from the gut, being composed of the mucosal barrier, submucosal glands and the mucosa-associated lymphoid tissue (Bengmark, 2002 ABSTRACT: Effects of the probiotic (PRO) Lactobacillus plantarum and of the combination of PRO and the prebiotic (PRE) inulin enriched with oligofructose (2%), and PRO with Lini oleum virginale (O) on counts of lactobacilli and coliforms and enzymatic activities in faeces of rats were studied. The rats (n = 60) were divided into 5 groups of 12 subjects. The animals were fed on a high fat diet (10%) for 8 weeks of experiment. Colon cancer was induced by the application of 1,2-dimethylhydrazine (DMH) twice a week in a dose of 20 mg/kg s.c. in groups G2-G5. The rats in group 1 (control 1) received a diet without any supplements. The rats in group 2 (control 2) received 1,2 DMH without any supplements. The rats in group 3 received PRO, group 4 PRO and PRE, and group 5 received PRO and O. A significant decrease (P < 0.05) of coliforms was found out after the application of PRO, PRO-O, and PRO-PRE in comparison with control group G2. Significantly higher (P < 0.05) counts of lactobacilli were determined after the application of PRO-O and PRO-PRE. Significantly lower (P < 0.001) activities of β-galactosidase, β-glucuronidase and α-glucosidase were observed in PRO, PRO-PRE and PRO-O, while in the case of the enzyme β-glucosidase the activity was lower only after the addition of PRO-O. The protective effect of lactobacilli was observed in the order PRO-O, PRO-PRE, and PRO. It was shown that combinations of PRO-O and PRO-PRE had a synergistic effect which was higher than the effect of administering only PRO.