Dissolution Rates of Mangosteen (Garcinia mangostana L.) Pericarps Extract Granules in Synthetic Human Gastrointestinal Fluid

Mangosteen (Garcinia mangostana L.) pericarps contain prenylated xanthone derivates, which exhibit some pharmacological activities, such as antiinflammatory, antihistamine, antibacterial, antivirus, antifungal, antioxidant, and antiulcerogenic. The purpose of this research was to study the dissolution rates of mangosteen pericarp extract granules in synthetic human gastrointestinal fluid at various pH and temperatures, which include experimental and modeling works. The granules were prepared by wet granulation of methanol extracts of mangosteen pericarps with addition of 25% w/v Arabic gum and 5% w/v maltodextrin. Dissolution rate study was performed by dissolving 0.5 g granules in 500 mL of 0.02M phosphate buffer solution with constant agitation at various pH (5.5, 6, 6.5, 7 and 7.5) and temperatures (30, 37 and 40oC) for two hours. Every 20 minutes, a liquid sample was withdrawn from the system for xanthone analysis. The results showed that mangosteen pericarps granules dissolution rates increased with pH under acidic condition. At pH 7.5 (basic condition), the dissolution rate was faster than that at pH 7. As expected, the dissolution rates were higher at higher temperatures. The semi empirical Korsmeyer-Peppas model showed its superiority over other models to predict the mangosteen pericarps granules dissolution rates. However, the mass transfer model proposed in this work also agreed well with the experimental data with error percentages closely similar to that of Korsmeyer-Peppas model

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

Background: The upper gastrointestinal tract plays a prominent role in human physiology as the primary site for enzymatic digestion and nutrient absorption, immune sampling, and drug uptake. Alterations to the small intestine microbiome have been implicated in various human diseases, such as non-alcoholic steatohepatitis and inflammatory bowel conditions. Yet, the physiological and functional roles of the small intestine microbiota in humans remain poorly characterized because of the complexities associated with its sampling. Rodent models are used extensively in microbiome research and enable the spatial, temporal, compositional, and functional interrogation of the gastrointestinal microbiota and its effects on the host physiology and disease phenotype. Classical, culture-based studies have documented that fecal microbial self-reinoculation (via coprophagy) affects the composition and abundance of microbes in the murine proximal gastrointestinal tract. This pervasive self-reinoculation behavior could be a particularly relevant study factor when investigating small intestine microbiota. Modern microbiome studies either do not take self-reinoculation into account, or assume that approaches such as single housing mice or housing on wire mesh floors eliminate it. These assumptions have not been rigorously tested with modern tools. Here, we used quantitative 16S rRNA gene amplicon sequencing, quantitative microbial functional gene content inference, and metabolomic analyses of bile acids to evaluate the effects of self-reinoculation on microbial loads, composition, and function in the murine upper gastrointestinal tract. Results: In coprophagic mice, continuous self-exposure to the fecal flora had substantial quantitative and qualitative effects on the upper gastrointestinal microbiome. These differences in microbial abundance and community composition were associated with an altered profile of the small intestine bile acid pool, and, importantly, could not be inferred from analyzing large intestine or stool samples. Overall, the patterns observed in the small intestine of non-coprophagic mice (reduced total microbial load, low abundance of anaerobic microbiota, and bile acids predominantly in the conjugated form) resemble those typically seen in the human small intestine. Conclusions: Future studies need to take self-reinoculation into account when using mouse models to evaluate gastrointestinal microbial colonization and function in relation to xenobiotic transformation and pharmacokinetics or in the context of physiological states and diseases linked to small intestine microbiome and to small intestine dysbiosis

A novel model to explain dietary factors affecting hypocalcaemia in dairy cattle

Most dairy cows exhibit different degrees of hypocalcaemia around calving because the gestational Ca requirements shift to the disproportionately high Ca requirements of lactation. Ca homeostasis is a robust system that effectively adapts to changes in Ca demand or supply. However, these adaptations often are not rapid enough to avoid hypocalcaemia. A delay in the reconfiguration of intestinal Ca absorption and bone resorption is probably the underlying cause of this transient hypocalcaemia. Several dietary factors that affect different aspects of Ca metabolism are known to reduce the incidence of milk fever. The present review describes the interactions between nutrition and Ca homeostasis using observations from cattle and extrapolations from other species and aims to quantitatively model the effects of the nutritional approaches that are used to induce dry cows into an early adaptation of Ca metabolism. The present model suggests that reducing dietary cation–anion difference (DCAD) increases Ca clearance from the blood by dietary induction of systemic acidosis, which results in hypercalciuria due to the loss of function of the renal Ca transient receptor potential vanilloid channel TRPV5. Alternatively, reducing the gastrointestinal availability of Ca by reducing dietary Ca or its nutritional availability will also induce the activation of Ca metabolism to compensate for basal blood Ca clearance. Our model of gastrointestinal Ca availability as well as blood Ca clearance in the transition dairy cow allowed us to conclude that the most common dietary strategies for milk fever prevention may have analogous modes of action that are based on the principle of metabolic adaptation before calving