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Natural compounds such as resveratrol, tannic acid, and quercetin may help to treat cancer. Tamoxifen is a non-steroidal anti-estrogen drug widely used in the treatment of patients with estrogen receptor-positive breast cancer. The aim of the study was to compare the effects of these natural compounds and tamoxifen in colon adenocarcinoma (CaCo-2) and breast adenocarcinoma (MCF-7) cell lines, on telomerase enzyme activity, cell viability, number of cells and DNA fragmentation. In this study to determine telomerase enzyme activity was used PCR-ELISA kit. To determine cell viability and number of cells were used tripan blue stain. DNA fragmentation was determined by DNA ladder isolation kit. Tannic acid was more effective than resveratrol, with respect to reduction in telomerase activity, cell viability and cell count in breast adenocarcinoma. Tannic acid and tamoxifen was more effective than resveratrol and quercetin telomerase activity, cell viability and cell count in colon adenocarcinoma. Flavonoids such as resveratrol, tannic acid and quercetin which was studied on, has benefical effects on cancer therapy. These effects such as decreasing telomerase enzyme activity, cell viability and number of cells and inducing DNA fragmentation (apoptosis) must be studied for assist to develop new therapeutic pathways. There should be much more sudies in order to discover resveratrol, tannic acid and quercetin and other potential medicines.

The aim of the study was to determine the relationship between anti-inflammatory effects of the natural polyphenolic compound tannic acid (CAS number: 1401-55-4) and myeloperoxidase (MPO) enzyme activity in paw edema model. Thirty-five female rats were divided into five groups. The paws of rats were injected subcutaneously in the plantar surface with formalin except for the control group. Indomethacin and tannic acid were intraperitoneally administered 1 h after formalin injection. The paws volume was measured by using vernier caliper. MPO enzyme activity was determined using 4-aminoantipyrine–phenol solution as the substrate for MPO-mediated oxidation by H2O2. About 17% and 13% edema inhibition has detected in the indomethacin-applied group, at the measurements run every other hour right after the treatment. An inhibition of 16% was found at the group treated with 25 mg/kg tannic acid. However, in the group treated with 50 mg/kg tannic acid, 15% and 7% of the edema inhibition was observed. Serum and paw tissue MPO activities were decreased in treated groups with indomethacin and tannic acid according to formalin control group. Our study results suggest that tannic acid may contribute to the treatment of inflammation by decreasing MPO enzyme activity, but the molecular mechanism is still not clear.

Hypertension is a major health problem with increasing prevalence around the world. Tannic acid is water-soluble polyphenol that is present in tea, green tea, coffee, red wine, nuts, fruits and many plant foods. It has been reported to serve as an antioxidant or a pro-oxidant depending on the type of cells and its concentration. The purpose of our study was to evaluate the effect of tannic acid on systolic blood pressure, oxidative stress and some urinary parameters in the rat model of essential hypertension. Blood pressures of all rats were measured using the tail-cuff method. The nitric oxide synthase inhibitor N (omega)-nitro-L-arginine was administered orally at a dose of 0.5 g/l/day for 15 days to rats in order to create an animal model of hypertension. Tannic acid was intraperitoneally injected at a dose of 50 mg/kg for 15 days. Superoxide dismutase, catalase activity and the concentration of malondialdehyde (MDA) were determined in blood plasma and homogenates of heart, liver and kidney. In order to evaluate renal functions, urine pH, urine volume, urine creatine, uric acid, and urea nitrogen values were measured. Compared with the hypertension group, a decrease in MDA concentrations of heart tissue (p \ 0.01), urea nitrogen values (p \ 0.01) and urine volumes (p \ 0.001) were established in hypertension ? tannic acid group. There was also a decrease in blood pressure values (20th and 30th days) of this group, but there was no a statistical difference according to hypertension group. The findings of our research show the effect of tannic acid in lowering blood pressure in hypertensive rats.

BackgroundMonosodium glutamate (MSG) is a widely-used flavor enhancer and stabilizer in ready-made or packaged foods. The excessive use of MSG has been shown to increase oxidative stress in different organ systems and causes glucose metabolism disorders, obesity, and coronary diseases.ObjectivesIn this study, the antioxidant activity of tannic acid was investigated experimentally with respect to its protective effects against overdosed MSG-induced oxidative stress in rats. The study took place in Turkey in August 2013.MethodsFour groups (n = 7) of three- to four-month-old Sprague-Dawley female rats were used in this study. The first group was the control, who were administered saline. The second group received tannic acid (50 mg/kg, 3 days) intraperitoneally (i.p.). The third group received MSG (2 g/kg, 7 days) i.p., and the fourth group received both tannic acid (50 mg/kg, 3 days, pretreatment) and MSG (2 g/kg, 7 days) i.p. The animals were euthanized ten days later. Blood was collected for determining the hematological values and blood glucose levels. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were determined in the brain, liver, and kidney homogenates, and in the erythrocyte hemolysate. Histopathological examination of the brain, liver, and kidneys was conducted through hematoxylin-eosin staining.ResultsThe data showed that the tannic acid treatment statistically decreased the MDA levels in the brain tissues of the group administered MSG and tannic acid (P < 0.001) when compared to the corresponding values of the control group. The SOD activities in the blood hemolysates of the MSG and tannic acid group increased when compared to the corresponding values for the MSG group (P < 0.01). Additionally, we found that pretreatment with tannic acid reduced blood glucose levels in comparison to the levels of the MSG group (P = 0.029). The results of our study show that tannic acid pretreatment in adult rats decreased blood glucose levels and oxidative stress.ConclusionsIn the literature, it was observed that short-term MSG exposure does not cause significant histological changes in the kidneys, liver, or brain cortex. These findings should be re-evaluated in additional long-term studies.

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Cancer chemopreventive agents are designed to reduce the incidence of tumorigenesis by intervening at one or more stages of carcinogenesis. This study aimed to determine the effects of resveratrol (RES) and tannic acid (TA), which are chemopreventive agents, on the nitric oxide synthase (NOS) levels that are effective for development of cancer in colon and breast cancer cell lines. The CaCo-2 (human colon carcinoma cell line) and MCF-7 (Michigan Cancer Foundation-7; human breast adenocarcinoma cell line) cells were grown in the laboratory. RES and TA were used to treat CaCo-2 and MCF-7 cells. Nitric Oxide Synthase Assay Kit was used to determine the NOS enzyme activity of CaCo-2 and MCF-7. Statistical differences between control and RES- and TA-treated cells were calculated using the Student's t-test for double comparison. It was observed that NO activity was generally decreased in CaCo-2 and MCF-7 cells, in which RES and TA were applied. Results suggest that the phenolic compounds RES and TA have different effects on NOS enzyme activity of the colon and breast cancer cells.