Biomedical subjects

Marilyn M Polansky

Publications and source records attributed to Marilyn M Polansky.

6 recordsLinked to original sources

PubMed2006

Whole cinnamon and aqueous extracts ameliorate sucrose-induced blood pressure elevations in spontaneously hypertensive rats.

OBJECTIVE: Many agents (nutrients, nutraceuticals, and drugs) that enhance insulin sensitivity and/or reduce circulating insulin concentrations lower blood pressure (BP). Recently, it was reported that cinnamon has the potential to favorably influence the glucose/insulin system. Accordingly, the purpose of the present study was to examine the effects of dietary cinnamon on systolic BP (SBP), and various glucose- and insulin-related parameters in spontaneously hypertensive rats (SHR). METHODS: In a series of three experiments, treated SHR eating sucrose and non sucrose containing diets were given various amounts of cinnamon, cinnamon extracts, or chromium. Then various parameters such as: body weight, systolic blood pressure, hematology and blood chemistries were followed for three to four weeks. RESULTS: Diets high in sucrose content are associated with insulin resistance and the elevation of SBP. Addition to diets of cinnamon (8% w/w) reduced the SBP of rats eating sucrose containing diets to virtually the same levels as SHR consuming non sucrose containing (only starch) diets. The presence of cinnamon in the diet also decreased the SBP of SHR consuming a non sucrose-containing diet, suggesting that cinnamon reduces more than just sucrose-induced SBP elevations--perhaps a genetic component(s) of the elevated BP as well. The effects of cinnamon on SBP tended to be dose-dependent. Cinnamon did not decrease the levels of blood glucose, but did lower circulating insulin concentrations. Aqueous extracts of cinnamon also decreased SBP and lowered the circulating levels of fructosamine. CONCLUSIONS: Cinnamon is used for flavor and taste in food preparation, but cinnamon may have additional roles in glucose metabolism and BP regulation. Therefore, BP regulation may not only be influenced favorably by limiting the amounts of dietary substances that have negative effects on BP and insulin function but also by the addition of beneficial ones, such as cinnamon, that have positive effects.

Animals↗

PubMed2005

Burn-induced alterations of chromium and the glucose/insulin system in rats.

Our objective was to demonstrate a role of chromium (Cr) in response to severe burn. A third-degree burn involving 20% of total body surface was applied under anaesthesia in accord with ethical guidelines. Chromium concentrations in liver decreased progressively and were non-detectable on days 5 and 10 following injury. In quadriceps muscle, Cr concentrations increased 6h after injury and then declined significantly within the first day and remained at these levels the following 9 days. Urinary Cr losses were also increased. Changes in kidney, brain and serum Cr were not significant. Non-fasting glucose rose 6h after injury and then returned to levels measured before the burn. There was a significant rise in corticosterone reaching a maximum the first day after injury that was accompanied by significant increases in circulating insulin and glucagon that were maximal after 2 days. Changes in IGF-1 were not significant. In summary, changes in Cr concentrations were associated with an early hyperglycemia, hyperinsulinemia and increased secretion of stress hormones. These observations strongly suggest a mobilization and utilization of Cr following severe burn. Additional studies are needed to document that improved Cr status might lead to improved recovery following burn.

Animals↗

PubMed2005

Water-soluble polymeric polyphenols from cinnamon inhibit proliferation and alter cell cycle distribution patterns of hematologic tumor cell lines.

To explore possible anti-cancer properties of water-soluble, polymeric polyphenols from cinnamon, three myeloid cell lines (Jurkat, Wurzburg, and U937) were exposed to increasing concentrations of an aqueous extract prepared from cinnamon (CE) for 24 h. Cell growth and cell cycle distribution patterns responded in a dose-dependent manner to CE. That is, an increase in the percentage of cells distributed in G2/M was observed in all three cell lines as the amount of CE increased. At the highest dose of CE, the percentage of Wurzburg cells in G2/M was 1.5- and 2.0-fold higher than those observed for Jurkat and U937 cells, respectively. Wurzburg cells lack the CD45 phosphatase and may be more sensitive to imbalances in signaling through kinase/phosphatase networks that promote growth. The results suggest the potential of CE to interact with phosphorylation/dephosphorylation signaling activities to reduce cellular proliferation in tandem with a block at the G2/M phase of the cell cycle.

Cell Cycle↗

PubMed2004

Isolation and characterization of polyphenol type-A polymers from cinnamon with insulin-like biological activity.

The causes and control of type 2 diabetes mellitus are not clear, but there is strong evidence that dietary factors are involved in its regulation and prevention. We have shown that extracts from cinnamon enhance the activity of insulin. The objective of this study was to isolate and characterize insulin-enhancing complexes from cinnamon that may be involved in the alleviation or possible prevention and control of glucose intolerance and diabetes. Water-soluble polyphenol polymers from cinnamon that increase insulin-dependent in vitro glucose metabolism roughly 20-fold and display antioxidant activity were isolated and characterized by nuclear magnetic resonance and mass spectroscopy. The polymers were composed of monomeric units with a molecular mass of 288. Two trimers with a molecular mass of 864 and a tetramer with a mass of 1152 were isolated. Their protonated molecular masses indicated that they are A type doubly linked procyanidin oligomers of the catechins and/or epicatechins. These polyphenolic polymers found in cinnamon may function as antioxidants, potentiate insulin action, and may be beneficial in the control of glucose intolerance and diabetes.

Antioxidants↗

PubMed2004

Stability and absorption of chromium and absorption of chromium histidinate complexes by humans.

Increased intake of chromium (Cr) often leads to improvements in glucose, insulin, lipids, and related variables in studies involving humans and experimental and farm animals. However, the results are often variable, depending not only on the selection of subjects but also dietary conditions and the form of supplemental Cr used. Our objective was to find a Cr supplement suitable for humans that was absorbed better than any of those available. Chromium absorption by six adult subjects, three males and three females, was determined based on the amount of Cr excreted in the urine in the initial 2 d following intake of 200 microg of Cr of the various forms of chromium tested. The absorption of the newly synthesized complexes was greatest for those containing histidine. Urinary Cr losses for six control subjects consuming 200 microg of Cr as Cr histidinate increased from basal levels of 256+/-48 to 3670+/-338 ng/d compared with 2082+/-201 ng for Cr picolinate, the currently most popular nutrient supplement, in the 48 h following Cr consumption. Chromium histidinate complexes were stable and absorption was similar to the initial values after more than 2 yr. Mixing of some of the complexes with starch, which was postulated to improve Cr absorption, was shown to essentially block Cr absorption within 1 mo. These data demonstrate that urinary Cr losses need to be determined because stability and absorption of the Cr complexes varies widely and could be responsible for the variability in some of the Cr supplementation studies. Chromium histidinate complexes are absorbed better than any of the Cr complexes currently available and need to be evaluated as Cr nutritional supplements.

Adult↗

PubMed2002

Tea enhances insulin activity.

The most widely known health benefits of tea relate to the polyphenols as the principal active ingredients in protection against oxidative damage and in antibacterial, antiviral, anticarcinogenic, and antimutagenic activities, but polyphenols in tea may also increase insulin activity. The objective of this study was to determine the insulin-enhancing properties of tea and its components. Tea, as normally consumed, was shown to increase insulin activity >15-fold in vitro in an epididymal fat cell assay. Black, green, and oolong teas but not herbal teas, which are not teas in the traditional sense because they do not contain leaves of Camellia senensis, were all shown to increase insulin activity. High-performance liquid chromatography fractionation of tea extracts utilizing a Waters SymmetryPrep C18 column showed that the majority of the insulin-potentiating activity for green and oolong teas was due to epigallocatechin gallate. For black tea, the activity was present in several regions of the chromatogram corresponding to, in addition to epigallocatechin gallate, tannins, theaflavins, and other undefined compounds. Several known compounds found in tea were shown to enhance insulin with the greatest activity due to epigallocatechin gallate followed by epicatechin gallate, tannins, and theaflavins. Caffeine, catechin, and epicatechin displayed insignificant insulin-enhancing activities. Addition of lemon to the tea did not affect the insulin-potentiating activity. Addition of 5 g of 2% milk per cup decreased the insulin-potentiating activity one-third, and addition of 50 g of milk per cup decreased the insulin-potentiating activity approximately 90%. Nondairy creamers and soy milk also decreased the insulin-enhancing activity. These data demonstrate that tea contains in vitro insulin-enhancing activity and the predominant active ingredient is epigallocatechin gallate.

Adipocytes↗