Effect of Annona squamosa leaf extract on human promyelocytic leukemia cells subjected to oxidative stress.

OBJECTIVES: Annona squamosa has beneficial properties. However, its cytotoxicity and antioxidative effects on human promyelocytic leukemia cells (HL60) deserve investigation. Therefore, the efficacy of its crude extracts in offsetting damage in HL60 cells subjected to oxidative stress was studied. METHODS: Crude extracts at different concentrations were incubated with HL60 cells. The beneficial properties of the plant extract against oxidative damage were evaluated post-induction of oxidative stress utilizing hydrogen peroxide. RESULTS: Extracts at concentrations 600 and 800 µg/mL were most effective at increasing the viability of damaged cells compared to the control group after 48 h of incubation. Significant increases in lipid peroxidation were observed in exposed cells treated with 600 µg/mL extract after 72 h of incubation. Superoxide dismutase (SOD) and catalase activities significantly increased in exposed cells after 24 h of incubation at all extract concentrations. Exposed cells treated with 600 and 1,000 µg/dL of the extract showed significantly increased catalase activity after 48 h, and a similar profile was maintained after 72 h of exposure. SOD activity in exposed cells remained significantly increased at all treatment concentrations after 48 and 72 h of incubation. Treatment with 400, 600, and 800 µg/mL of the extract resulted in significantly increased reduced glutathione levels compared to the other groups after 24 and 72 h of incubation. However, after 48 h of incubation, significant increases were noted in glutathione levels in exposed cells incubated with either 400, 800, or 1,000 µg/mL extract. CONCLUSIONS: The findings suggest that A. squamosa might effectively protect against oxidative damage in a time and extract concentration-dependent manner.

The Effect of Acute and Chronic Thermotherapy on Type 2 Diabetic Skeletal Muscle Gene Expression and Inflammatory Markers.

BACKGROUND: Type 2 diabetes (T2D) is a chronic illness associated with resistance to or defective insulin secretion. This study investigates the effects of thermotherapy on cell viability, gene expression and inflammation in skeletal muscle cell lines. METHODS: Healthy and T2D human skeletal muscle cell lines (HSMM and D-HSMM, respectively) were subjected to acute or chronic thermo-therapy (AT or CT, respectively). CT consisted of a 30 min exposure to 40 °C, three times a week for three weeks; AT was a one-time exposure. RESULTS: A significant decrease in D-HSMM cell viability percentage followed AT; however, no significant change occurred in CT. HSMM yielded the highest elevations of genes following CT. In D-HSMM, both treatments yielded gene upregulation. Both treatments significantly down-regulated IL-1ß, IL-6, IL-10 and TNF-α in HSMM. AT significantly decreased IL-1ß, IL-6 and upregulated IL-10 and TNF-α levels in D-HSMM, while CT yielded a reduction in IL-4, TNF-α and an upregulation of IL-6 and IL-10. CONCLUSIONS: An increase in gene expression indicates actin activity and cellular responses, suggesting an increase in transcriptional regulation. The upregulation of IL-6 and IL-10 in D-HSMM negatively correlated with a decrease in TNF-α and IL-1ß, indicating improved adverse inflammatory effects associated with the disease.

New Frontiers for the Use of IP6 and Inositol Combination in Treating Diabetes Mellitus: A Review.

Inositol, or myo-inositol, and associated analog molecules, including myo-inositol hexakisphosphate, are known to possess beneficial biomedical properties and are now being widely studied. The impact of these compounds in improving diabetic indices is significant, especially in light of the high cost of treating diabetes mellitus and associated disorders globally. It is theorized that, within ten years, the global population of people with the disease will reach 578 million individuals, with the cost of care projected to be approximately 2.5 trillion dollars. Natural alternatives to pharmaceuticals are being sought, and this has led to studies involving inositol, and myo-inositol-hexakisphosphate, also referred to as IP6. It has been reported that IP6 can improve diabetic indices and regulate the activities of some metabolic enzymes involved in lipid and carbohydrate metabolism. Current research activities have been focusing on the mechanisms of action of inositol and IP6 in the amelioration of the indices of diabetes mellitus. We demonstrated that an IP6 and inositol combination supplement may regulate insulin secretion, modulate serum leptin concentrations, food intake, and associated weight gain, which may be beneficial in both prediabetic and diabetic states. The supplement attenuates vascular damage by reducing red cell distribution width. Serum HDL is increased while serum triglycerides tend to decrease with consumption of the combination supplement, perhaps due to the modulation of lipogenesis involving reduced serum lipase activity. We also noted increased fecal lipid output following combination supplement consumption. Importantly, liver function was found to be preserved. Concurrently, serum reactive oxygen species production was reduced, indicating that inositol and IP6 supplement consumption may reduce free radical damage to tissues and organs as well as serum lipids and blood glucose by preserving liver function. This review provides an overview of the findings associated with inositol and IP6 supplementation in the effective treatment of diabetes with a view to proposing the potential mechanisms of action.

Effects of Moringa oleifera Leaf Extract on Human Promyelocytic Leukemia Cells Subjected to Oxidative Stress.

Oxidative stress is initiated by reactive oxygen species, the primary factor in many chronic diseases. Moringa oleifera possesses strong antioxidant properties due to the presence of various phytochemicals. In this study, we investigated the effect of M. oleifera leaf extract on markers of oxidative stress in HL60 cells exposed to oxidative stress. HL60 cells were incubated with different concentrations of M. oleifera leaf extract, and cells were harvested for viability assays on days 1, 2, and 3. Antioxidant indexes (malondialdehyde, reduced glutathione, superoxide dismutase, and catalase) were measured on days 1, 2, and 3. Supplementation with the moringa leaf extract at all concentrations resulted in significant reductions in lipid peroxidation in cells that were or were not incubated in an environment with excess oxidative stress. The most significant reduction in this parameter occurred after 24 h of incubation. The results show that reductions seen in this parameter may be due to the modulation of the endogenous antioxidant defense system by extract supplementation. Cell viability was also improved in cells incubated in moringa leaf extract at concentrations of 800 and 1000 µg/mL. This finding, however, did not corroborate with lipid peroxidation results at 1000 µg/mL extract supplementation. Further investigations are needed to clarify the underlying mechanism responsible for increased cell viability at this concentration. We can, therefore, conclude that the moringa leaf extract offered added protection from oxidative stress within the first 24 h, as well as increasing cell viability at certain concentrations.

Combined Inositol Hexakisphosphate and Inositol Supplement Consumption Improves Serum Alpha-Amylase Activity and Hematological Parameters in Streptozotocin-Induced Type 2 Diabetic Rats.

This study evaluated the effect of combined inositol hexakisphosphate (IP6) and inositol supplement on organ weight, intestinal ATPase activities, complete blood count, and serum analytes in streptozotocin (STZ)-induced type 2 diabetic rats. High-fat diet and a single intraperitoneal injection of streptozotocin (35 mg/kg body weight) were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. The diabetic groups were then treated with either combined IP6 and inositol supplement or glibenclamide for four weeks. Organ weights, intestinal ATPase activities, complete blood count, serum α-amylase, total protein, albumin, and globulin content were determined. Pancreatic weight was significantly reduced while relative kidney and liver weights were elevated in the group treated with combined IP6 and inositol supplement compared to the nondiabetic control. Serum α-amylase activity for the glibenclamide and combination treated groups was significantly improved compared to that of the untreated diabetic group. Red cell distribution width percentage was significantly lower in the combination treated group compared to that in the untreated diabetic group, while intestinal ATPase activities were unaffected by the treatment regime. Combined IP6 and inositol supplement consumption may protect people with diabetes from increased risk of cardiovascular diseases due to the supplement's ability to maintain red cell distribution width percentage towards the normal control group.

Effects of Uvaria chamae Root Extracts on Blood Glucose, Inflammatory Markers, Lipid Profile, Liver and Renal Status in Streptozotocin-induced Diabetic Rats.

Uvaria chamae roots are traditionally used in the treatment of diabetes in many parts of the world, but the use of the extracts in the treatment of diabetes has not been scientifically validated. Thirty-six Sprague Dawley rats were assigned by weight into six groups [6 rats per group, average body weight 265.23 ± 7.20g]. Diabetes mellitus was induced by a single administration of streptozotocin (60 mg/kg) intraperitoneally. Normal and diabetic rats were treated with aqueous or ethanolic extract (300 mg/kg body weight/day/rat) of Uvaria chamae for 35 days. Rats were allowed free access to food, and extract added to the water bottle. Animals were euthanized on day 35 after an overnight fast and blood was collected for glucose, renal function, liver, serum lipid profile, and inflammatory markers assays. The blood glucose levels decreased by 38% and 53% in the diabetic rats administered aqueous or ethanolic extract respectively compared to an increase in the diabetic control (45%). The levels of TC, TG, LDL-C, VLDL-C, TG/HDL-C, and non-HDL-C were decreased in untreated rats, while the HDL-C was increased when the extracts were administered. There was a diminishing trend in IL-6, TNF-α and IL-1ß levels in the treated diabetic groups. Serum creatinine level was slightly elevated in the diabetic group administered ethanolic extract. Overall, the consumption of Uvaria chamae extracts lowered blood glucose levels, lipid profile and increased HDL-C, while the IL-6 was decreased. The non-significant changes in renal function parameters indicated no adverse effects on the kidney in this short-term study.

Pancreatic and renal function in streptozotocin-induced type 2 diabetic rats administered combined inositol hexakisphosphate and inositol supplement.

Diabetes mellitus, as a result of microvascular and macrovascular injury, causes organ dysfunction in a wide variety of tissues. The objective of this study was to investigate the effect of combined inositol hexakisphosphate and inositol supplement on renal and pancreatic integrity in type 2 diabetic rats. Thirty male Sprague-Dawley rats were divided into five groups (n=6 per group). Type 2 diabetes was induced in three groups using high-fat diet combined with a single dose of streptozotocin (35mg/kg body weight, intraperitoneally). Two of the diabetic groups were treated with combined IP6 and inositol or glibenclamide. Serum biochemical markers of kidney damage kidney, antioxidant status (superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) and lipid peroxidation were measured. Histomorphological and morphometric examinations of the H&E stained pancreas were also carried out. The administration of combined IP6 and inositol supplement resulted in 64% and 27% increase in CAT activities and GSH levels respectively and a 25% decrease in lipid peroxidation level compared to the diabetic control. Serum uric acid, creatinine and BUN levels in the combination treated group was comparable to the normal control. Examination of H&E stained pancreatic sections showed a significant increase (107%) in the number of islets in the combined IP6 and inositol treated group compared to the untreated diabetic group. Overall, the treatment of type 2 diabetic rats with combined IP6 and inositol supplement resulted in the improvement of renal and pancreatic function.

Effects of combined inositol hexakisphosphate and inositol supplement on antioxidant activity and metabolic enzymes in the liver of streptozotocin-induced type 2 diabetic rats.

Diabetes mellitus is associated with elevated reactive oxygen species, lipid abnormalities, reduced antioxidant activity and organ damage. This study examines the effects of combined inositol hexakisphosphate (IP6) and inositol supplement on antioxidant levels and other biochemical parameters in the liver of type 2 diabetic rats. Five groups of Sprague-Dawley rats were studied. Six rats were fed normal diet (non-diabetic control), while 24 rats were fed high-fat diet (HFD) for 4 weeks. Diabetes was induced in 18 of the rats fed HFD by intraperitoneal administration of streptozotocin. The diabetic rats were separated into three groups namely: combined IP6 and inositol, glibenclamide and diabetic control. The non-diabetic group fed high-fat diet was classified as a high-fat control group. For the final four weeks of the experiment, all rats were fed normal diet and given their respective treatment regimes. Hepatic antioxidant status, metabolic enzyme activity, lipid profile, peroxidative damage and liver histology, as well as, serum aminotransferase and alkaline phosphatase activities, and total bilirubin concentration were assessed. Treatment with combined IP6 and inositol supplement significantly increased liver reduced glutathione and high-density lipoprotein levels while liver triglyceride levels and serum alkaline phosphatase activity were significantly reduced by 27%, 50%, 38.5%, and 69.2% respectively compared to the diabetic control. Hepatic superoxide dismutase, catalase, glucose-6-phosphate dehydrogenase activities were significantly upregulated by 55%, 26% and 53% respectively in the diabetic rats treated with combined IP6 and inositol compared to the diabetic control. Combined IP6 and inositol treatment resulted in the preservation of liver cell integrity and improved antioxidant status in type 2 diabetic rats.

The effect of combined inositol hexakisphosphate and inositol supplement in streptozotocin-induced type 2 diabetic rats.

Inositol hexakisphosphate (IP6) and inositol both regulate insulin secretion, but their combined use in the management of diabetes deserves investigation. The combined effects of IP6 and inositol supplementation were investigated in streptozotocin-induced type 2 diabetic rats. The following groups of rats were studied for 8 weeks: non-diabetic control, non-diabetic high-fat diet control, diabetic untreated, diabetic rats treated with the combination of IP6 and inositol (650 mg/kg bw) and diabetic rats treated with glibenclamide (10 mg/kg bw). High-fat diet and streptozotocin were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. Body weight, blood glucose, glycated haemoglobin, insulin, serum leptin, HOMA-insulin resistance scores, intestinal amylase activity, serum and faecal lipids and food and fluid consumption were measured. Treatment with the combination significantly reduced blood glucose (306 ± 53 mg/dl) and insulin resistance score (1.93 ± 0.45) compared with diabetic controls (522 ± 24 mg/dl and 5.1 ± 0.69 respectively). Serum leptin (2.8 ± 0.6 ng/dl) and faecal triglycerides (108 ± 8 mg/dl) were significantly increased in rats treated with the combination compared with the diabetic control (1.8 ± 0.06 ng/dl and 86 ± 4 mg/dl). Serum triglyceride (47 ± 5.1 mg/dl), total cholesterol (98 ± 3.2 mg/dl) and food intake (26 ± 0.3 g) were significantly reduced by 45%, 25% and 25%, respectively, in rats treated with the combination compared with the diabetic control. Inositol and IP6 combined supplementation may be effective in the management of type 2 diabetes mellitus and related metabolic disorders by regulating some aspects of lipid and carbohydrate metabolism.

Investigation of the cytotoxicity, antioxidative and immune-modulatory effects of Ligusticum porteri (Osha) root extract on human peripheral blood lymphocytes.

OBJECTIVE: Ligusticum porteri is a traditional Native American herb. The roots of L. porteri are traditionally used in the treatment of many diseases, however, its cytotoxicity, antioxidative and immune-modulatory effects need to be investigated. In this study, we evaluated the effects of the root extract at different doses on human peripheral blood lymphocytes (PBLs). METHODS: The lymphocytes were incubated with different concentrations of the root extracts (0, 50, 100, 200, and 400 µg/mL) and harvested every 6 h for 2 d (P<0.05). The protective effect of the herb against oxidative damage was determined by inducing oxidative stress with the administration of 50 µmol/L of hydrogen peroxide (H2O2). RESULTS: Treatments with L. porteri at 200 and 400 µg/mL increased the viability of PBLs. The deleterious effect of H2O2 was ameliorated by 400 µg/mL L. porteri treatment. Addition of 400 µg/mL L. porteri reduced lipid peroxidation in stressed PBLs by 94% (P<0.05). Treatment with 400 µg/mL of L. porteri resulted in a 26.4% increase of reduced glutathione levels. Activities of superoxide dismutase and catalase increased by 17.5% and 55.2% respectively, when stressed PBLs were treated with 400 µg/mL L. porteri for 2 d (P<0.05). Treatment with 400 µg/mL L. porteri increased interferon-γ and interleukin-2 expressions in H2O2-challenged PBLs (P<0.05), however, the root extract did not cause a significant difference in interleukin-10 levels compared to the control (P>0.05). CONCLUSION: The findings suggest that L. porteri might be a potential immune-modulating agent involving protective effects against oxidative damage.

Oxidative Stress Parameters and Erythrocyte Membrane Adenosine Triphosphatase Activities in Streptozotocin-induced Diabetic Rats Administered Aqueous Preparation of Kalanchoe Pinnata Leaves.

BACKGROUND: Diabetes mellitus is a chronic metabolic disease that according to the World Health Organization affects more than 382 million people. The rise in diabetes mellitus coupled with the lack of an effective treatment has led many to investigate medicinal plants to identify a viable alternative. OBJECTIVE: To evaluate red blood cell (RBC) membrane adenosine triphosphatase (ATPase) activities and antioxidant levels in streptozotocin-induced diabetic rats administered aqueous preparation of Kalanchoe pinnata leaves. MATERIALS AND METHODS: Diabetes mellitus was induced in rats by a single administration of streptozotocin (60 mg/kg). Diabetic rats were then treated with aqueous K. pinnata preparation (three mature leaves ~ 9.96 g/70 kg body weight or about 0.14 g/kg body weight/day) for 30 days. Serum glucose, RBC membrane ATPase activities, and antioxidant levels were determined. RESULTS: We noted weight loss and reduced food consumption in the treated diabetic group. Serum glucose levels were reduced in the treated diabetic group compared to the other groups. Superoxide dismutase activity and glutathione levels were not significantly elevated in the treated group compared to the diabetic group. However, serum catalase activity was significantly (P < 0.05) increased in the treated diabetic group compared to the other groups. Serum thiobarbituric acid reactive substances were not significantly altered among the groups. There was a significant (P < 0.05) increase in Mg(2+) ATPase activity and a nonsignificant increase in Na(+)/K(+) ATPase activity in the RBC membrane of the treated diabetic group compared to the diabetic group. CONCLUSION: The consumption of aqueous preparation of K. pinnata may accrue benefits in the management of diabetes by lowering oxidative stress often associated with the disease and improving the availability of cellular magnesium through an increase in the magnesium ATPase pump in the RBC membrane for increased cellular metabolism of glucose through the glycolytic pathway. SUMMARY: We noted weight loss and reduced food consumption in the diabetic rats treated with K. pinnata preparationSerum glucose levels were reduced in diabetic rats treated with K. pinnata preparationSerum catalase activity was significantly (P < 0.05) increased in diabetic rats treated with K. pinnata preparationWe also noted a significant (P < 0.05) increase in Mg(2+) ATPase activity in the RBC membranes of diabetic rats treated with K. pinnata preparationOverall, the consumption of aqueous preparation of K. pinnata lowered oxidative stress often associated with diabetes and improved availability of cellular magnesium through an increase in magnesium ATPase pump in the RBC membrane.

Antiproliferative activities of lesser galangal (Alpinia officinarum Hance Jam1), turmeric (Curcuma longa L.), and ginger (Zingiber officinale Rosc.) against acute monocytic leukemia.

Acute monocytic leukemia (AML M5 or AMoL) is one of the several types of leukemia that are still awaiting cures. The use of chemotherapy for cancer management can be harmful to normal cells in the vicinity of the target leukemia cells. This study assessed the potency of the extracts from lesser galangal, turmeric, and ginger against AML M5 to use the suitable fractions in neutraceuticals. Aqueous and organic solvent extracts from the leaves and rhizomes of lesser galangal and turmeric, and from the rhizomes only of ginger were examined for their antiproliferative activities against THP-1 AMoL cells in vitro. Lesser galangal leaf extracts in organic solvents of methanol, chloroform, and dichloromethane maintained distinctive antiproliferative activities over a 48-h period. The turmeric leaf and rhizome extracts and ginger rhizome extracts in methanol also showed distinctive anticancer activities. The lesser galangal leaf methanol extract was subsequently separated into 13, and then 18 fractions using reversed-phase high-performance liquid chromatography. Fractions 9 and 16, respectively, showed the greatest antiproliferative activities. These results indicate that the use of plant extracts might be a safer approach to finding a lasting cure for AMoL. Further investigations will be required to establish the discriminatory tolerance of normal cells to these extracts, and to identify the compounds in these extracts that possess the antiproliferative activities.

Effects of phytic acid and exercise on some serum analytes in rats orally exposed to diets supplemented with cadmium.

Cadmium is an environmental pollutant of increasing worldwide concern. It has been reported to be high in the soil where food crops are grown in some parishes of Jamaica. Surprisingly, no adverse effect of cadmium has been reported among the Jamaican population. However, phytic acid has also been shown to be high in some food crops grown in Jamaica. In this study, we evaluated the effects of phytic acid (1 %) and exercise on the metabolism of cadmium (5 mg cadmium/kg body weight) in rats. Five groups of rats were fed as follows: rats fed control diet, control diet supplemented with cadmium and subjected to exercise, control diet supplemented with phytic acid plus cadmium and subjected to exercise, control diet supplemented with cadmium plus phytic acid, and control diet supplemented with cadmium only. The animals were fed for 4 weeks and then sacrificed. Blood samples were collected for some biochemical assays. Percentage weight loss (28.42 %) was greatest in the group that had cadmium supplement only. The group fed control diet supplemented with cadmium only displayed increased liver enzymes and electrolytes except for the significant decrease in bicarbonate compared to other test groups. Similarly, blood urea nitrogen and uric acid were increased in the group fed cadmium supplement only compared to other test groups. Total cholesterol trended downwards in the test groups compared to control. These observations suggest that consumption of diet high in phytic acid with relatively high physical activity may be protective against the adverse effects of cadmium.

Effect of bauxite mineralized soil on residual metal levels in some post harvest food crops in Jamaica.

The concentrations of nine residual metals in some Jamaican foods were determined using inductively coupled plasma mass spectrometry technique. Cadmium concentration was highest in yellow yam (0.21 mg/kg). Sweet potato had the highest concentrations of lead (0.31 mg/kg), arsenic (0.70 mg/kg) and mercury (0.35 mg/kg). Samples from Grove Place exceeded the regulatory limits of 0.1 mg/kg for cadmium, lead and arsenic and 0.05 mg/kg for mercury. Significant correlations were found between soil and agricultural produce concentrations for cadmium and lead (r(2) ≥ 0.5). These results suggest that the elements were available in soluble forms in the soil for absorption by food crops.

Evaluation of the performance of urine albumin, creatinine and albumin-creatinine ratio assay on two POCT analyzers relative to a central laboratory method.

BACKGROUND: The evaluation of microalbumin, creatinine and albumin-creatinine ratio is very important in patients with diabetes for the early detection of kidney disease and the identification of patients at risk for complications from diabetes or hypertension. METHODS: A total of 88 spot urine samples previously analyzed using the Vitros 5,1 FS (creatinine) and Beckman Coulter Immage (microalbumin) located in the central laboratory and having microalbumin and creatinine values within the Afinion and DCA Vantage reportable ranges were run on 2 point of care (POC) instruments (Siemens DCA Vantage and Axis-Shield Afinion). RESULTS: The mean values for the DCA Vantage were: 42.6 mg/l for albumin, 10.3 mol/l for creatinine, and 5.4 mg/mol for ACR. For the Afinion AS100, the mean values were: 48.5mg/l for albumin, 9.5 mol/l for creatinine, and 6.7 mg/mol for ACR. The mean values obtained for CL were: 40.8 mg/l for albumin, 10.0 mol/l for creatinine, and 5.4 mg/mol for ACR. All POC analyzers showed good correlation to the central laboratory tests for microalbumin, creatinine and albumin creatinine ratio (ACR) for Afinion (R(2)=0.954, 0.974, and 0.964, respectively) and DCA Vantage (R(2)=0.989, 0.987, and 0.991, respectively). With the exception of the DCA Vantage ACR (p=0.53), the levels of microalbumin, creatinine and ACR obtained for the Afinion and DCA Vantage instruments as compared to the CL were statistically different (p<0.05). The inter and intraday imprecision for both POC instruments was <2.9% and total imprecision <8.7%. CONCLUSIONS: The 2 instruments evaluated in this study were in good agreement with the quantitative laboratory results and thus can be used for microalbumin, creatinine and ACR assays at the POC. However, facilities using Afinion will have to use different normal range for ACR.

Hemoglobin A1c: assessment of three POC analyzers relative to a central laboratory method.

BACKGROUND: Glycosylated hemoglobin evaluation is very important for assessing the control of diabetes. Since the use of point-of-care (POC) devices for monitoring HbA1c is increasing, it is important to determine how these devices compare in relation to instrumentation used in the central laboratory (CL). METHODS: Eighty-eight randomly selected samples previously analyzed using the Bio-Rad Variant™ II Hemoglobin Testing System were run on three POC Analyzers (Siemens DCA Vantage™ Analyzer, Axis-Shield Afinion™ AS100 Analyzer, and Bio-Rad In2it™ Analyzer). RESULTS: All POC instruments showed good correlation to the CL method (R(2)>0.95 for all methods). HbA1c levels obtained using Variant II (mean=7.9; 95% CI=7.5-8.3%) and In2it (mean=7.9; 95% C.I.=7.5-8.2%) instruments were found to have no statistical mean difference (p=0.21), while the values obtained using DCA Vantage (mean=7.2% C.I.=6.9-7.5%) and Afinion (mean=7.3% C.I.=7.0-7.6%) instruments were different (p<0.001) from those of the CL method. The Afinion and DCA Vantage instruments increasingly underestimated the HbA1c compared to the CL as the HbA1c values increased. These differences were even more striking when the estimated average glucose is calculated. CONCLUSIONS: Despite significant variation of results among the POC instruments evaluated relative to the CL method and pending resolution of HbA1c standardization issues, we conclude that all of the POC instruments can be used for HbA1c determination if clinicians are given instrument specific reference ranges.

Jamaican bitter yam sapogenin: potential mechanisms of action in diabetes.

Sapogenin has been proposed to be the active component responsible for the beneficial effects of Jamaican bitter yam (Dioscorea polygonoides) in the management of diabetes. Most of the research activities on bitter yam have focused on the role sapogenin play in the management of diabetes. Changes in weight, activities of carbohydrate digestive and transport enzymes, alterations in the intestinal morphology, changes in blood lipids, reduction in lipid peroxidation and the prevention of liver damage associated with diabetes have all been attributed to bitter yam sapogenin supplementation. Also, the possible exploitation of bitter yam for nutraceutical/pharmaceutical purposes is based on the high saponin content. There are however, concerns about the beneficial claims of the findings especially with regard to the possible adverse effects that may accrue in the clinical applications. This review therefore provides an overview of the findings in this research area with a view to proposing the potential mechanisms whereby the supplement of bitter yam sapogenin extract exert its hypoglycemic and hypolipidemic properties and the probable adverse effects in diabetes mellitus.

Bone and faecal minerals and scanning electron microscopic assessments of femur in rats fed phytic acid extract from sweet potato (Ipomoea batatas).

Phytic acid was extracted from sweet potato (Ipomoea batatas) and fed to Wistar rats with or without zinc for 3 weeks. Animals were then sacrificed and bone and faecal minerals were assessed. The ultra-structure of the bones was examined via scanning electron microscopy. Phytic acid extract or commercial phytic acid supplemented diets (D + Zn + PE or D + PE) displayed reduced bone calcium levels (101.27 +/- 59.11 and 119.27 +/- 45.36 g/kg) compared to the other test groups. Similarly, reduced calcium were observed in the control groups (D + Zn and D) fed formulated diets with or without zinc supplementation (213.14 +/- 15.31 and 210 +/- 6.88 g/kg) compared to the other test groups. The group fed supplemented commercial phytic acid diet (D + CP) demonstrated the lowest femur magnesium (3.72 +/- 0.13 g/kg) while the group fed phytic acid extract supplementation (D + PE) recorded the highest level (4.84 +/- 0.26 g/kg) amongst the groups. Femur iron was highest in the group fed commercial phytic acid supplemented diet (D + CP -115.74 +/- 2.41 g/kg) compared to the other groups. Faecal magnesium levels were significantly higher in the two test groups fed phytic acid extract with or without zinc (D + Zn + PE or D + PE) compared to all other groups. All the groups which had phytic acid supplemented diets had significantly thinner bone in the trabecular region, compared to the groups fed formulated diet or zinc supplemented formulated diet (D or D + Zn). These observations suggest that the consumption of foods high in phytic acid may contribute to a reduction in the minerals available for essential metabolic processes in rats.

In vitro availability of some essential minerals in commonly eaten processed and unprocessed Caribbean tuber crops.

The levels of three essential minerals Ca, Fe and Mg and the extent of their availability were assessed in four commonly eaten Caribbean tuber crops [dasheen (Xanthosoma spp.), Irish potato (Solanum tuberosum), sweet potato (Ipomoea batatas) and yellow yam (Dioscorea cayenensis)] in their processed and unprocessed states. Calcium was highest in cooked dasheen (5150+/-50 mg/kg) while Magnesium was highest in uncooked Irish potato (3600+/-200 mg/kg). There was no significant loss of calcium from the food samples upon cooking. All the uncooked food samples displayed higher levels minerals assessed compared to the cooked samples except for cooked Irish potato that recorded the level of iron (182.25+/-8.75 mg/kg). Availability of these minerals in the cooked and uncooked tubers crops upon digestion also showed a similar pattern. In conclusion, the consumption of these tuber crops in the Caribbean may not be responsible for the reported cases of iron deficiency in the region. However, the availability of minerals from these tuber crops when consumed with other foods (the usual practice in the Caribbean) needs further investigation.

Intestinal lipids and minerals in streptozotocin-induced diabetic rats fed bitter yam (Dioscorea polygonoides) sapogenin extract.

Yam is the leading form of staple for millions of people in the tropical and subtropical countries. They are good sources of carbohydrate. However, the protein content of yam is low. The effect of bitter yam sapogenin extract or commercial diosgenin on faecal minerals and intestinal lipids in streptozotocin-induced diabetic rats was studied. Sapogenin extract or commercial diosgenin (1%) supplemented diets were fed to diabetic male Wistar rats for three weeks. Bitter yam sapogenin extract or commercial diosgenin did not significantly alter faecal magnesium, calcium, and zinc excretion but significantly decreased faecal sodium and potassium excretion. The absorption of iron was impaired by bitter yam sapogenin extract or commercial diosgenin during the first week of feeding. Bitter yam sapogenin extract or commercial diosgenin supplements significantly decreased intestinal lipids towards normal. Faecal lipids excreted was significantly higher in diabetic rats fed bitter yam sapogenin extract or commercial diosgenin for the three weeks period compared to the diabetic control group. These results show that bitter yam sapogenin extract or commercial diosgenin does not have the same effects on mineral excretion in diabetes. There was no direct correlation between the decrease in excretion of mono-valent cations and the activity of intestinal Na+/K+ATPase.