Effects of melamine and cyanuric acid on renal function and structure in rats

Melamine has been used to increase the amount of measurable nitrogen which is a component of protein. The renal toxicity of melamine has been reported in infants and animals that consumed a mixture of melamine in their food products. This study aimed to investigate the effects of melamine on rat renal function using clearance and histological techniques. Animals were divided into 3 groups: vehicle control, 400 mg/kg melamine and mixture of 400 mg/kg melamine and 400 mg/kg cyanuric acid (p.o., daily for three days). The results showed that blood urea nitrogen level significantly increased in the rats treated with the mixture of melamine and cyanuric acid. The urine flow rate, glomerular filtration rate, renal plasma flow and urinary sodium and potassium excretion rate significantly decreased when compared to vehicle control. These results suggested both glomeruli and renal tubules of rats treated with mixture of melamine and cyanuric acid were damaged. Histological study also confirmed these findings and showed significant glomerular atrophy and dilated renal tubules. Numerous clear brownish-yellow crystals were also found in the distal tubule, collecting tubule and papillary duct. However, rats solely treated with melamine showed no significant difference in renal function or structures

Proximate composition, phytochemical analysis and toxicity assessment of extracts of caulerpa lentillifera using autoclave- and microwave-assisted extractions

Caulerpa lentillifera is a marine alga widely cultured and consumed in Asia and Oceania. Emerging green techniques are currently popular for phytochemical extraction. Therefore, this study aimed to investigate the proximate compositions, phytochemicals, and antioxidant properties of the C. lentillifera extracts using autoclave-assisted and microwaveassisted extraction methods (A-CLE and M-CLE, respectively). The toxicity of extracts was tested against human normal colon cells and freshwater crustacean Daphnia magna. We found that crude lipid, ash and moisture contents in A-CLE were lower than those in M-CLE, while crude protein and crude carbohydrate were higher in A-CLE. Total flavonoid content in A-CLE (1.474 ± 0.046 mg QE g-1 extract) was higher than that in M-CLE (1.179 ± 0.054 mg QE g-1 extract). There was no difference in total phenolic contents, triterpenoid contents and antioxidant activities between the extracts. The IC50 of A-CLE (12,260 ± 197 µg mL-1) was higher than that of M-CLE (10,950 ± 169 µg mL-1). In the acute toxicity test, the LC50 of A-CLE against D. magna (7.50 ± 0.28 g L-1) was lower than LC50 of M-CLE (8.76 ± 0.26 g L-1). This study suggest that autoclave-assisted and microwave-assisted extractions are effective green methods of extracting C. lentillifera. This study will be useful for further studies of C. lentillifera extracts to improve human and animal health

Effects of Sargassum plagiophyllum extract pretreatment on tissue histology of constipated mice

Purpose: To evaluate the toxicity of the dried seaweed, Sargassum plagiophyllum, extract (SPE) pretreatment in constipated mice.Methods: The dried seaweed powder was mixed with distilled water and extracted by autoclave at 121°C. Antioxidant activity of the extract was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Human normal colon cells were pretreated with SPE at 0 - 100 μg/mL for 24 h before challenging them with 100 μM hydrogen peroxide (H2O2). Intracellular reactive oxygen species (ROS) were quantified using 2',7'- dichlorodihydrofluorescein diacetate (H2DCFDA). Male ICR mice were pretreated for 14 consecutive days with SPE at 100, 500 and 1,000 mg/kg or lactulose at 500 mg/kg. Body weight and food intake were recorded daily. Constipation was induced with loperamide on days 12, 13 and 14 and fecal pellets evacuated over a 4-hr period. The ileum, liver, kidney, and spleen were collected for histopathological examination.Results: The IC50 for the radical scavenging capacity of SPE was 343.90 ± 4.21 μg/mL compared to 14.14 ± 0.71 μg/mL for ascorbic acid. Pretreatment with SPE was significantly reduced ROS production in human normal colon cells. Oral administration of all doses of SPE and lactulose for 14 consecutive days had no effect on food intake or body weight when compared to the normal control group. Defecation was significantly more frequent in mice pretreated with SPE at 100 mg/kg than in the constipation control group. Histopathological examination of the ileum, liver, kidney and spleen of pretreated constipated mice revealed no toxic effect from either SPE or lactulose. On the other hand, the loss of mucus-producing cells in the ileum of constipated mice was significantly lower in mice pretreated with SPE.Conclusions: These findings support the safety of SPE supplementation and may broaden itsapplication in clinical fields as an alternative drug or supplement for constipation management

Effects of plant oligosaccharides derived from dragon fruit on gut microbiota in proximal and distal colon of mice

Prebiotic oligosaccharides are used as supplements to improve colon health. Oligosaccharides derived from dragon fruit (DFO) are a mixture of fructo-oligosaccharides (FOS), and have prebiotic properties that increase beneficial bacteria in vitro. This study aimed to investigate changes in gut microbiota in the colon of mice fed a diet supplemented with DFO. Treatment groups were fed 100, 500, and 1000 mg/kg of DFO, 1000 mg/kg FOS and distilled water. The results showed that DFO did not change the body weight of mice, but altered microbiota in the proximal and distal colon. Populations of Blautia, Parabacteroides, and Bacteroides were among the highest proportions of bacteria represented after all treatments. Lactobacillus was also found in the proximal and distal colon. Moreover, qPCR results showed that Bifidobacteria increased in the distal colon of mice treated with 100 and 1000 mg/kg DFO for 14 days, while Lactobacilli increased in the proximal colon of mice treated with 500 mg/kg DFO for 7 days. In contrast, Enterococci decreased in the proximal colon of mice that were given 100, 500, and 1000 mg/kg of DFO and 1000 mg/kg of FOS for 14 days. These results suggested that DFO is capable of increasing populations of beneficial bacteria while decreasing populations of some other bacteria

Sargassum plagiophyllum Extract Enhances Colonic Functions and Modulates Gut Microbiota in Constipated Mice

Constipation is a symptom that is widely found in the world’s population. Various dietary supplementations are used to relieve and prevent constipation. Seaweed is widely used for its health benefits. In this study, we aimed to investigate the effects of Sargassum plagiophyllum extract (SPE) on functions of the gastrointestinal tract and gut microbiota. The results show that SPE pretreatment increased the frequency of gut contraction, leading to reduce gut transit time. SPE pretreatment also significantly increased the secretion of Cl− and reduced Na+ absorption, increasing fecal water content in constipated mice (p < 0.05). In addition, the Bifidobacteria population in cecal contents was significantly higher in constipated mice pretreated with 500 mg/kg SPE for 14 days than in untreated constipated mice (p < 0.05). Our findings suggest that SPE can prevent constipation in loperamide-induced mice. This study may be useful for the development of human food supplements from S. plagiophyllum, which prevent constipation