Gastrointestinal Effects on the Antioxidant and Immunomodulatory Properties of South African Fynbos Honey.

The Fynbos biome, Western Cape Province, South Africa, produces a unique honey from Apis mellifera capensis. The bioactivity of Fynbos (FB1-FB6) honeys and Manuka, unique manuka factor 15+ (MAN UMF15+) honey subjected to simulated in vitro digestion, was compared. The effect of each phase of digestion on the antioxidant properties and nitric oxide- (NO-) associated immunomodulatory effects was determined. The total phenolic content of MAN (UMF15+) was higher than that of FB honeys, and following digestion, the percentage bioaccessibility (BA) was 68.6% and 87.1 ± 27.0%, respectively. With the Trolox equivalent antioxidant capacity assay, the activity of FB1 and FB6 was similar to MAN (UMF15+) but reduced for FB2, FB3, FB4, and FB5 with a %BA of 77.9% for MAN (UMF15+) and 78.2 ± 13.4% for FB. The oxygen radical absorbance capacity of MAN (UMF15+) and FB honeys was similar and unaltered with digestion. In a cellular environment, using colon adenocarcinoma (Caco-2) cells, both undigested and the gastric digested honey reduced 2,2'-azobis-(2-amidinopropane) dihydrochloride- (AAPH-) mediated peroxyl radical formation. In contrast, following gastroduodenal digestion, the formation of reactive oxygen species (ROS) was increased. In murine macrophage (RAW 264.7) cells, all honeys induced different levels of NO which was significantly increased with digestion for MAN (UMF15+) and FB1. In LPS/IFN-γ stimulated RAW 264.7 macrophages, only undigested MAN (UMF15+) effectively reduced NO levels, and with digestion, NO scavenging activity of MAN (UMF15+) was reduced but increased for FB5 and FB6. In a noncellular environment, MAN (UMF15+), FB1, FB2, and FB6 scavenged NO, and with digestion, this activity was maintained. This study has identified that undigested and gastric-digested FB honey has antioxidant properties with strong potential anticancer effects following gastroduodenal digestion, related to ROS formation. MAN (UMF15+) had anti-inflammatory effects which were lost postdigestion, and in contrast, FB5 and FB6 had anti-inflammatory effects postdigestion.

Adverse cardiovascular effects of exposure to cadmium and mercury alone and in combination on the cardiac tissue and aorta of Sprague-Dawley rats.

The aim of this study was to identify cardiovascular effects of relevant concentrations of Cd and Hg alone and in combination as a mixture in water. This was achieved by administering to male Sprague-Dawley rats via gavage 0.62 mg/kg Cd or 1.23 mg/kg Hg, or a combination of 0.62 mg/kg Cd and 1.23 mg/kg Hg in the co-exposure group for 28 days. Concentrations were the rat equivalence dosages of 1,000 times the World Health Organization's limits of 0.003 mg/L and 0.006 mg/L for Cd and Hg, respectively, for water. With termination, blood levels of the metals were increased. For all metal exposed groups, histological evaluation and transmission electron microscopy of the myocardium revealed myofibrillar necrosis, increased fibrosis, vacuole formation and mitochondrial damage. Cd caused the most mitochondrial damage while Hg to a greater degree induced fibrosis. In the aorta, both Cd and Hg also increased collagen deposition adversely altering the morphology of the fenestrated elastic fibers in the tunica media. Co-exposure resulted in increased cardiotoxicity with increased mitochondrial damage, fibrosis and distortion of the aortic wall as a result of increased collagen deposition, as well as altered elastin deposition, fragmentation and interlink formation. These are typical features of oxidative damage that correlates with a phenotype of premature ageing of the CVS that potentially can lead to hypertension and premature cardiac failure.

Inhibition of α-glucosidase and α-amylase by herbal compounds for the treatment of type 2 diabetes: A validation of in silico reverse docking with in vitro enzyme assays.

BACKGROUND: α-Amylase and α-glucosidase are important therapeutic targets for the management of type 2 diabetes mellitus. The inhibition of these enzymes decreases postprandial hyperglycemia. In the present study, compounds found in commercially available herbs and spices were tested for their ability to inhibit α-amylase and α-glucosidase. These compounds were acetyleugenol, apigenin, cinnamic acid, eriodictyol, myrcene, piperine, and rosmarinic acid. METHODS: The enzyme inhibitory nature of the compounds was evaluated using in silico docking analysis with Maestro software and was further confirmed by in vitro α-amylase and α-glucosidase biochemical assays. RESULTS: The relationships between the in silico and in vitro results were well correlated; a more negative docking score was associated with a higher in vitro inhibitory activity. There was no significant (P > .05) difference between the inhibition constant (Ki ) value of acarbose, a widely prescribed α-glucosidase and α-amylase inhibitor, and those of apigenin, eriodictyol, and piperine. For α-amylase, there was no significant (P > .05) difference between the Ki value of acarbose and those of apigenin, cinnamic acid, and rosmarinic acid. The effect of the herbal compounds on cell viability was assessed with the sulforhodamine B (SRB) assay in C2C12 and HepG2 cells. Acetyleugenol, cinnamic acid, myrcene, piperine, and rosmarinic acid had similar (P > .05) IC50 values to acarbose. CONCLUSIONS: Several of the herbal compounds studied could regulate postprandial hyperglycemia. Using herbal plants has several advantages including low cost, natural origin, and easy cultivation. These compounds can easily be consumed as teas or as herbs and spices to flavor food.

Oral exposure to cadmium and mercury alone and in combination causes damage to the lung tissue of Sprague-Dawley rats.

Environmental presence and human exposure to heavy metals in air and cigarette smoke has led to a worldwide increase in respiratory disease. The effects of oral exposure to heavy metals in liver and kidney structure and function have been widely investigated and the respiratory system as a target is often overlooked. The aim of the study was to investigate the possible structural changes in the lung tissue of Sprague-Dawley rats after oral exposure for 28 days to cadmium (Cd) and mercury (Hg), alone and in combination at 1000 times the World Health Organization's limit for each metal in drinking water. Following exposure, the general morphology of the bronchiole and lungs as well as collagen and elastin distribution was evaluated using histological techniques and transmission electron microscopy. In the lungs, structural changes to the alveoli included collapsed alveolar spaces, presence of inflammatory cells and thickening of the alveolar walls. In addition, exposure to Cd and Hg caused degeneration of the alveolar structures resulting in confluent alveoli. Changes in bronchiole morphology included an increase in smooth muscle mass with luminal epithelium degeneration, detachment and aggregation. Prominent bronchiole-associated lymphoid tissue was present in the group exposed to Cd and Hg. Ultrastructural examination confirmed the presence of fibrosis where in the Cd exposed group, collagen fibrils arrangement was dense, while in the Hg exposed group, additional prominent elastin was present. This study identified the lungs as target of heavy metals toxicity following oral exposure resulting in cellular damage, inflammation and fibrosis and increased risk of respiratory disease where Hg showed the greatest fibrotic effect, which was further, aggravated in combination with Cd.

Ultrastructural, Confocal and Viscoelastic Characteristics of Whole Blood and Plasma After Exposure to Cadmium and Chromium Alone and in Combination: An Ex Vivo Study.

BACKGROUND/AIMS: Heavy metal pollution is increasing in the environment, contaminating water, food and air supplies. This can be linked to many anthropogenic activities. Heavy metals are absorbed through the skin, inhalation and/or orally. Irrespective of the manner of heavy metal entry in the body, the blood circulatory system is potentially the first to be affected following exposure and adverse effects on blood coagulation can lead to associated thrombotic disease. Although the plasma levels and the effects of cadmium (Cd) and chromium (Cr) on erythrocytes and lymphocytes have been described, the environmental exposure to heavy metals are not limited to a single metal and often involves metal mixtures, with each metal having different rates of absorption, different cellular, tissue, and organ targets. Therefore the aim of this study is to investigate the effects of the heavy metals Cd and Cr alone and whether Cr synergistically increases the effect of Cd on physiological important processes such as blood coagulation. METHODS: Human blood was exposed to the heavy metals ex vivo, and thereafter morphological analysis was performed with scanning electron- and confocal laser scanning microscopy (CLSM) in conjunction with thromboelastography®. RESULTS: The erythrocytes, platelets and fibrin networks presented with ultrastructural changes, including varied erythrocytes morphologies, activated platelets and significantly thicker fibrin fibres in the metal-exposed groups. CLSM analysis revealed the presence of phosphatidylserine on the outer surface of the membranes of the spherocytic erythrocytes exposed to Cd and Cr alone and in combination. The viscoelastic analysis revealed only a trend that indicates that clots that will form after heavy metal exposure, will likely be fragile and unstable especially for Cd and Cr in combination. CONCLUSION: This study identified the blood as an important target system of Cd and Cr toxicity.

Effects of chronic exposure to mercury and cadmium alone and in combination on the coagulation system of Sprague-Dawley rats.

Water contamination with heavy metals may adversely affect our health. High metal levels lead to changes in blood coagulation processes, increasing the risk for cardiovascular disease. Exposure is not limited to a single metal but usually involves a mixture of metals. In this study 24 male Sprague-Dawley rats were exposed to cadmium (Cd) and mercury (Hg), alone and in combination, for 28 days at dosages equivalent to 1000 times the World Health Organization water limits. Scanning electron microscopy analysis revealed that both metals caused platelet activation. Cd significantly increased fibrin fibers thickness and caused aggregation and formation of dense matted deposits (DMDs). Hg reduced fibrin network formation. In the combination group, Hg appeared to augment the effect of Cd, and the presence of extensive DMDs or aggregates between the fibers, with no changes to the actual fibrin thickness, was observed.

Effects of metals cadmium and chromium alone and in combination on the liver and kidney tissue of male Spraque-Dawley rats: An ultrastructural and electron-energy-loss spectroscopy investigation.

Heavy metal pollution has increased in the last decades. Water sources are contaminated and human exposure is often long term exposure to variable amounts of different metals. In this study, male Sprague-Dawley rats were exposed via oral gavage for 28 days to cadmium (Cd) and chromium (Cr), alone and in combination at concentrations 1000 times the human World Health Organization's acceptable water limits. Rat equivalent dosages were used. Blood markers of liver and kidney function were measured, changes to cellular morphology was determined with transmission electron microscopy and the intracellular metal localisation was determined with the electron energy-loss spectroscopy and energy filtered transmission electron microscopy analysis. Both Cd and Cr caused changes to the nuclear and mitochondrial membranes and irregular chromatin condensation of hepatocytes. Cr exposure caused dilation of the rough endoplasmic reticulum (rER). The combination caused nuclear and mitochondrial membrane damage as well as irregular chromatin condensation. In the kidney tissue, Cd caused irregular chromatin condensation in the cells of the proximal convoluted tubule (PCT). Cr caused changes to the outer nuclear and mitochondrial membrane and chromatin structure. The combination group caused membrane damage, irregular chromatin condensation and rER changes in the PCT. All the metal groups showed damage to the endothelial cells and pedicles, but not to the mesangial cells. Cd and Cr bio-accumulation was observed in the nucleus, mitochondria and rER of the liver and kidney and therefore are responsible for the cellular observed damage that can cause functional changes to the tissues and organs.

How methylglyoxal kills bacteria: An ultrastructural study.

Antibacterial activity of honey is due to the presence of methylglyoxal (MGO), H2O2, bee defensin as well as polyphenols. High MGO levels in manuka honey are the main source of antibacterial activity. Manuka honey has been reported to reduce the swarming and swimming motility of Pseudomonas aeruginosa due to de-flagellation. Due to the complexity of honey it is unknown if this effect is directly due to MGO. In this ultrastructural investigation the effects of MGO on the morphology of bacteria and specifically the structure of fimbriae and flagella were investigated. MGO effectively inhibited Gram positive (Bacillus subtilis; MIC 0.8 mM and Staphylococcus aureus; MIC 1.2 mM) and Gram negative (P. aeruginosa; MIC 1.0 mM and Escherichia coli; MIC 1.2 mM) bacteria growth. The ultrastructural effects of 0.5, 1.0 and 2 mM MGO on B. substilis and E. coli morphology was then evaluated. At 0.5 mM MGO, bacteria structure was unaltered. For both bacteria at 1 mM MGO fewer fimbriae were present and the flagella were less or absent. Identified structures appeared stunted and fragile. At 2 mM MGO fimbriae and flagella were absent while the bacteria were rounded with shrinkage and loss of membrane integrity. Antibacterial MGO causes alterations in the structure of bacterial fimbriae and flagella which would limit bacteria adherence and motility.